Change search
Refine search result
12 1 - 50 of 100
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Andersson, Anders G.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Papathanasiou, T.D.
    Department of Mechanical Engineering, University of Thessaly, 38 334 Volos, Greece.
    Lundström, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Flow through a two-scale porosity material2009In: Research Letters in Materials Science, ISSN 1687-6822, E-ISSN 1687-6830, article id 701512Article in journal (Other academic)
    Abstract [en]

    Flow through a two-scale porous medium is here investigated by a unique comparison between simulations performed with computational fluid dynamics and the boundary element method with microparticle image velocimetry in model geometries.

    Download full text (pdf)
    fulltext
  • 2. Andersson, Anders G.
    et al.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Papathanasiou, Thanasis
    Lundström, Staffan
    Fluid flow through porous media with dual scale porosity2008In: Proceedings of the 19th International Symposium on Transport Phenomena (ISTP-19): Reykjavik, Iceland, August 17-21, 2008 / [ed] Sigurdur Brynjolfsson; Olafur Petur Palsson; Jong H. Kim, University of Iceland, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science , 2008Conference paper (Refereed)
    Abstract [en]

    Flow in two scale porous media takes place in applications such as advanced composites manufacturing. Knowledge of this flow is of general importance and is crucial for filtration mechanisms when functional filler-particles are added to the liquid resin impregnating the fibrous preform. Means to model and experimentally visualise this flow is here investigated. In particular simulations performed with computational fluid dynamics and the boundary element method are compared to micro particle image velocimetry in a model geometry.

    Download full text (pdf)
    FULLTEXT01
  • 3. Baart, Pieter
    et al.
    Green, Torbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Li, Jinxia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet
    SKF Engineering & Research Center, Nieuwegein.
    Contaminant particle migration in a double restriction seal2013In: Proceedings of the STLE Annual Meeting and Exhibition 2013, Detroit MI, USA., STLE , 2013, p. 125-Conference paper (Refereed)
    Abstract [en]

    Microparticle image velocimetry (μPIV) is used to measure the grease velocity profile in small seal-like geometries and the radial migration of contaminant particles is predicted. In the first part, the influence of shaft speed, grease type, and temperatures on the flow of lubricating greases in a narrow double restriction sealing pocket is evaluated. Such geometries can be found in, for example, labyrinth-type seals. In a wide pocket the velocity profile is one-dimensional and the Herschel-Bulkley model is used. In a narrow pocket, it is shown by the experimental results that the side walls have a significant influence on the grease flow, implying that the grease velocity profile is two-dimensional. In this area, a single empirical grease parameter for the rheology is sufficient to describe the velocity profile.In the second part, the radial migration of contaminant particles through the grease is evaluated. Centrifugal forces acting on a solid spherical particle are calculated from the grease velocity profile. Consequently, particles migrate to a larger radius and finally settle when the grease viscosity becomes large due to the low shear rate. This behavior is important for the sealing function of the grease in the pocket and relubrication

  • 4. Baart, Pieter
    et al.
    Green, Torbjörn
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Li, Jinxia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    The influence of speed, grease type, and temperature on radial contaminant particle migration in a double restriction seal2011In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 54, no 6, p. 867-877Article in journal (Refereed)
    Abstract [en]

    Microparticle image velocimetry (μPIV) is used to measure the grease velocity profile in small seal-like geometries and the radial migration of contaminant particles is predicted. In the first part, the influence of shaft speed, grease type, and temperatures on the flow of lubricating greases in a narrow double restriction sealing pocket is evaluated. Such geometries can be found in, for example, labyrinth-type seals. In a wide pocket the velocity profile is one-dimensional and the Herschel-Bulkley model is used. In a narrow pocket, it is shown by the experimental results that the side walls have a significant influence on the grease flow, implying that the grease velocity profile is two-dimensional. In this area, a single empirical grease parameter for the rheology is sufficient to describe the velocity profile. In the second part, the radial migration of contaminant particles through the grease is evaluated. Centrifugal forces acting on a solid spherical particle are calculated from the grease velocity profile. Consequently, particles migrate to a larger radius and finally settle when the grease viscosity becomes large due to the low shear rate. This behavior is important for the sealing function of the grease in the pocket and relubrication.

  • 5.
    Baart, Pieter
    et al.
    SKF Engineering & Research Center, Nieuwegein.
    Lugt, Piet
    SKF Engineering & Research Center, Nieuwegein.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Green, Torbjörn
    Li, Jinxia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Sealing improvements by grease selection in double lip seals and labyrinth seals2012In: 17th ISC: International Sealing Conference ; Stuttgart, Germany, Sept. 13 - 14, 2012, Frankfurt am Main: Fachverband Fluidtechnik im VDMA e.V , 2012Conference paper (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 6.
    Barabash, Victoria
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Ejemalm, Johnny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Kuhn, Thomas
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Milz, Mathias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Molin, Sven
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Johansson, Jonny
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Masters Programs in Space Science and Engineering in Northern Sweden2017Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 7.
    Castro, Marley
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Felicetti, L.
    School of Aerospace Transport and Manufacturing, Cranfield University, Cranfield, MK43 0AL, United Kingdom.
    Sadeghi, Soheil
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Satpute, Sumeet
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Barabash, Victoria
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    de Oliveira, Élcio Jeronimo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Laufer, René
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Multi-Cubesat Mission For Auroral Acceleration Region Studies2021In: IAC 2021 Congress Proceedings, 72nd International Astronautical Congress (IAC), Dubai, United Arab Emirates, International Astronautical Federation (IAF) , 2021, article id 66544Conference paper (Refereed)
    Abstract [en]

    The Auroral Acceleration Region (AAR) is a key region in understanding the Magnetosphere-Ionosphere interaction. To understand the physical, spatial and temporal features of the region, multi-point measurements are required. Distributed small-satellite missions such as constellations of multiple nano satellites (for example multi-unit CubeSats) would enable such type of measurements. The capabilities of such a mission will highly depend on the number of satellites - one reason that makes low-cost platforms like CubeSats a very promising choice. In a previous study, the state-of-the-art of miniaturized payloads for AAR measurements was analyzed and evaluated and capabilities of different multi-CubeSat configurations equipped with such payloads in addressing different open questions in AAR were discussed. In this paper the mission analysis and possible mission design, as well as necessary technology developments of such multi-CubeSat mission are identified and presented.

  • 8.
    Duenas Dobrowolski, Jan
    et al.
    Department of Design Fundamentals and Fluid-Flow Machinery, Wrocaw University of Technology, Wrocaw, Poland.
    Gawlinski, Marek
    Department of Design Fundamentals and Fluid-Flow Machinery, Wrocaw University of Technology, Wrocaw, Poland.
    Paszkowski, Maciej
    Department of Fundamentals of Machine Design and Tribology, Wrocaw University of Technology, Wrocaw, Poland.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Experimental Study of Lubricating Grease Flow inside the Gap of a Labyrinth Seal Using Microparticle Image Velocimetry2018In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 61, no 1, p. 31-40Article in journal (Refereed)
    Abstract [en]

    In this study, the flow of lubricating greases in a labyrinth seal geometry is studied using microparticle image velocimetry (µPIV). The aim is to evaluate the grease velocity distribution inside the gap of a labyrinth seal and to find a relationship between the grease consistency and the transferred speed from the rotating ring in order to choose the correct grease as a sealing medium. In addition, the grease flow characteristics are important for the understanding of fracture due to grease layer displacement. For these purposes, four greases with different rheological properties were used in µPIV experiments. It was found that the grease consistency plays a crucial role in speed development as well as the grease composition and presence of a slip effect at the grease–rotating wall interface.

  • 9.
    Farré-Lladós, Josep
    et al.
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    Casals-Terré, Jasmina
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    Voltas, Jordi
    Department of Graphic Expression, UPC - Technical University of Catalonia.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    The use of Rapid Prototyping techniques (RPT) to manufacture micro channels suitable for high operation pressures and µPIV2016In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 22, no 1, p. 67-76Article in journal (Refereed)
    Abstract [en]

    Purpose– This paper aims to present a new methodology to manufacture micro-channels suitable for high operating pressures and micro particle image velocimetry (μPIV) measurements using a rapid-prototyping high-resolution 3D printer. This methodology can fabricate channels down to 250 μm and withstand pressures of up to 5 ± 0.2 MPa. The manufacturing times are much shorter than in soft lithography processes. Design/methodology/approach– The novel manufacturing method developed takes advantage of the recently improved resolution in 3D printers to manufacture an rapid prototyping technique part that contains the hose connections and a micro-channel useful for microfluidics. A method to assemble one wall of the micro-channel using UV curable glue with a glass slide is presented – an operation required to prepare the channel for μPIV measurements. Once built, the micro-channel has been evaluated when working under pressure and the grease flow behavior in it has been measured using μPIV. Furthermore, the minimum achievable channels have been defined using a confocal microscopy study. Findings– This technique is much faster than previous micro-manufacturing techniques where different steps were needed to obtain the micro-machined parts. However, due to current 3D printers ' resolutions (around 50 μm) and according to the experimental results, channels smaller than 250-μm2 cross-section should not be used to characterize fluid flow behaviors, as inaccuracies in the channel boundaries can deeply affect the fluid flow behavior. Practical implications– The present methodology is developed due to the need to validate micro-channels using μPIV to lubricate critical components (bearings and gears) in wind turbines. Originality/value– This novel micro-manufacturing technique overcomes current techniques, as it requires less manufacturing steps and therefore it is faster and with less associated costs to manufacture micro-channels down to 250-μm2 cross-section that can withstand pressures higher than 5 MPa that can be used to characterize microfluidic flow behavior using μPIV.

  • 10.
    Farré-Lladós, Josep
    et al.
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Casals-Terré, Jasmina
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    New solution to preent excessive wear in wind turbine gears2014In: Society of Tribologists and Lubrication Engineers Annual Meeting and Exhibition 2014: Lake Buena Vista, United States, 18 - 22 May 2014, Society of Tribologists and Lubrication Engineers , 2014, Vol. 2, p. 548-550Conference paper (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 11.
    Farré-Lladós, Josep
    et al.
    Department of Mechanical Engineering, UPC - Technical University of Catalonia, KIC InnoEnergy S.E. - Location Iberia, Barcelona.
    Casals-Terré, Jasmina
    Department of Mechanical Engineering, UPC - Technical University of Catalonia, KIC InnoEnergy S.E. - Location Iberia, Barcelona.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    New Lubrication Device to Minimize Wear at the Pitch Gear2015Conference paper (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 12.
    Farré-Lladós, Josep
    et al.
    Department of Mechanical Engineering, UPC - Technical University of Catalonia, KIC InnoEnergy S.E. - Location Iberia, Barcelona.
    Casals-Terré, Jasmina
    Department of Mechanical Engineering, UPC - Technical University of Catalonia, KIC InnoEnergy S.E. - Location Iberia, Barcelona.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    New Lubrication Device to Minimize Wear at the Pitch Gear2015Conference paper (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 13.
    Farré-Lladós, Josep
    et al.
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Casals-Terré, Jasmina
    Department of Mechanical Engineering, UPC - Technical University of Catalonia.
    Embedded Micro-nozzles in the Pitch Gear Deddendum to Minimize Wear at Zero Degree Position2015Conference paper (Refereed)
  • 14.
    Farré-Lladós, Josep
    et al.
    Mechanical Engineering Department, UPC - Technical University of Catalonia, Terrassa.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Casals-Terré, Jasmina
    Mechanical Engineering Department, UPC - Technical University of Catalonia, Terrassa.
    New method for lubricating wind turbine pitch gears using embedded micro-nozzles2017In: Journal of Mechanical Science and Technology, ISSN 1738-494X, E-ISSN 1976-3824, Vol. 31, no 2, p. 797-806Article in journal (Refereed)
    Abstract [en]

    The increase of power generated by wind turbines has increased the stresses applied in all of its components, thereby causing premature failures. Particularly, pitch and yaw gears suffer from excessive wear mainly caused by inappropriate lubrication. This paper presents a novel method to automatically lubricate the wind turbine pitch gear during operation. A micro-nozzle to inject fresh grease continuously between the teeth in contact was designed, manufactured, and installed in a test bench of a 2 MW wind turbine pitch system. The test bench was used to characterize the fatigue behavior of the gear surface using conventional wind turbine greases under real cyclic loads. Measurements of wear evolution in a pitch gear with and without micro-nozzle show a decrease of 70 % of the wear coefficient after 2×104 cycles.

  • 15.
    Farré-Lladós, Josep
    et al.
    Mechanical Engineering Department, UPC, Technical University of Catalonia, 08222 Terrassa, Spain.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Casals-Terré, Jasmina
    Mechanical Engineering Department, UPC, Technical University of Catalonia, 08222 Terrassa, Spain.
    Leckner, Johan
    Axel Christiernsson International AB, SE-449 11 Nol, Sweden.
    Westbroek, René
    Axel Christiernsson International AB, SE-449 11 Nol, Sweden.
    On the Flow Dynamics of Polymer Greases2022In: Lubricants, ISSN 2075-4442, Vol. 10, no 4, article id 66Article in journal (Refereed)
    Abstract [en]

    In this paper, the flow dynamics of polymer greases was investigated using micro-particle image velocimetry. Polymer greases have a different thickener structure, compared to widely used lithium-based greases, and they have the well-known ability to release oil. How these properties affect grease deformation and its ability to flow is investigated and compared to the corresponding behavior of a lithium complex grease with the same consistency. Two main tests were carried out, where velocity profiles in a straight channel were measured and analyzed, and velocity evolution during the transition period from a no-flow to a fully-established flow was measured, respectively. It was found that the polymer grease flow dynamics is different from that of the lithium grease. This indicates that the internal structure of the grease and the grease ability to bleed oil have a strong influence on the deformation on a global scale, which in turn entails other lubricating abilities for the two grease types.

    Download full text (pdf)
    fulltext
  • 16.
    Giacomini, Enrico
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    A Survey on Drones for Planetary Exploration: Evolution and Challenges2022In: 2022 30th Mediterranean Conference on Control and Automation (MED), IEEE, 2022, p. 583-590Conference paper (Refereed)
    Abstract [en]

    During the last decade, the efforts in space exploration have increased massively and led to a need for new ways to examine planets and other celestial bodies. The modern tendency is to create spacecraft able to scout the surface from a higher point of view, where drones have shown to be most helpful. Even if the benefits brought by this type of technology are considerable, the challenges are still difficult to overcome. This article presents a comprehensive literature review on drone technologies for planetary exploration, focusing mainly on the difficulties encountered. Considerable complications derive from the unknown environment, affecting most of the design, the mathematical model of the body, its controllability, and overall levels of autonomy. Various solutions to these challenges are proposed based on past and future missions. Furthermore, a look into the future gives an idea of possible technological developments and ways to provide the most efficient aerial exploration of other planets.

  • 17.
    Giacomini, Enrico
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nikolakopoulos, George
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Drones for Planetary Exploration: Modeling Challenges2022In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå: Luleå tekniska universitet, 2022Conference paper (Other academic)
    Download full text (pdf)
    fulltext
  • 18.
    Green, Torbjörn
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Baart, Pieter
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Li, Jinxia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Visualisering och kvantifiering av fettströmning i lagertätningar med µPIV2011Conference paper (Other academic)
    Download full text (pdf)
    FULLTEXT01
  • 19.
    Green, Torbjörn M.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Baart, Pieter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements. SKF Engineering and Research Centre, P.O. Box 2350, 3430 , DT, Nieuwegein, The Netherlands.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet M.
    SKF Engineering and Research Centre, P.O. Box 2350, 3430 , DT, Nieuwegein, The Netherlands.
    Li, Jinxia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    A new method to visualize grease flow in a double restriction seal using microparticle image velocimetry2011In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 54, p. 784-792Article in journal (Refereed)
    Abstract [en]

    A new method to visualize and quantify grease flow in between two sealing lips or, in general, a double restriction seal is presented. Two setups were designed to mimic different types of seals; that is, a radial and an axial shaft seal. The flow of the grease inside and in between the sealing restrictions was measured using microparticle image velocimetry. The results show that grease flow due to a pressure difference mainly takes place close to the rotating shaft surface with an exponentially decaying velocity profile in the radial direction. Consequently, contaminants may be captured in the stationary grease at the outer radius, which explains the sealing function of the grease.

  • 20.
    Hamedi, Naser
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Modelling of Flexible Fibres in Viscous Fluid Flow2019Conference paper (Refereed)
    Abstract [en]

    The current study relates to the development of a multiphase model of flexible fibre suspensions. An understanding of the rheology and dynamics of the deformation of such suspension is desirable in order to be able to fully disclose the flow behaviour from very low to very high shear rates. We present an approach for numerically simulating the dynamics of flexible fibres employing a particle-level method. This is performed by investigating the fibre dynamics against several orbit classes - i.e. rigid, springy, flexible and complex rotation of the fibres [1-3] enabling the model to have all degrees of freedom (translation, rotation, bending and twisting). The three-dimensional Navier-Stokes equations which describes the fluid motion are employed while the fibrous phase of the fluid is modeled as chains of fiber segments interacting with the fluid through viscous- and drag forces. The simulations are performed using OpenFOAM and the numerical outcomes are validated against experimental data.The purpose of the modelling framework applied in this work is to enable the numerical model to be extended to a 4-way coupling model, capturing shear thinning, shear thickening and the yield stress properties of a fibrous fluid suspension.

  • 21.
    Hamedi, Naser
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    On the deformation of fibrous suspensions2019Conference paper (Refereed)
    Abstract [en]

    An understanding of the rheology and dynamics of the deformation of fibrous suspension as a multiphase fluid is important in order to be able to fully disclose the flow behaviour from very low to very high shear rates. In this study, a flexible fibre model has been implemented in an open source Computational Fluid Dynamics code. The three-dimensional Navier-Stokes equations which describe the fluid motion are employed while the fibrous phase of the fluid is modeled as chains of fiber segments interacting with the fluid through viscous- and drag forces. The aim of this study is to investigate the fibre dynamics against several orbit classes - i.e. rigid, springy, flexible and complex rotation of the fibres1-3 enabling the model to have all degrees of freedom - translation, rotation, bending and twisting. The simulations are performed using the OpenFOAM open source software.

    Download full text (pdf)
    fulltext
  • 22.
    Hamedi, Naser
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    On the Interaction of Side-By-Side Circular Cylinders in Viscoplastic Fluids2019In: Fluids, E-ISSN 2311-5521, Vol. 4, no 2, article id 93Article in journal (Refereed)
    Abstract [en]

    In this paper, the static interaction of a train of three cylinders in a Bingham fluid is studiednumerically using Computational Fluid Dynamics. The variation of drag forces for the cylinders inseveral configurations is investigated. Positions of the particles in relation to the reference particleare recognized by the separation distance between the cylinders. A steady state field is considered,with Bingham numbers between 5 and 150. Several separation distances (d) were considered, such that2.0D d 6.0D where D is the cylinder diameter. The Reynolds number was chosen in the range of5 Re 40. In particular, the eect of the separation distance, Reynolds number and Bingham numberon the shape and size of the unyielded regions was investigated. The functional dependence of thisregion and the drag coecient is explored. The present results reveal the significant influence of thegap between the cylinders on the drag force and the shape of the unyielded regions surrounding thecylinders. It was found that there are several configurations in which the drag forces over the first andthe third cylinders are almost equal depending on variation of the Bi, Re and the separation distance.

  • 23.
    Hamedi, Naser
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Simulation of Flexible Fibre Particle Interaction with a Single Cylinder2021In: Processes, ISSN 2227-9717, Vol. 9, no 2, article id 191Article in journal (Refereed)
    Abstract [en]

    In the present study, the flow of a fibre suspension in a channel containing a cylinder was numerically studied for a very low Reynolds number. Further, the model was validated against previous studies by observing the flexible fibres in the shear flow. The model was employed to simulate the rigid, semi-flexible, and fully flexible fibre particle in the flow past a single cylinder. Two different fibre lengths with various flexibilities were applied in the simulations, while the initial orientation angle to the flow direction was changed between 45° ≤ θ ≤ 75°. It was shown that the influence of the fibre orientation was more significant for the larger orientation angle. The results highlighted the influence of several factors affecting the fibre particle in the flow past the cylinder.

  • 24.
    Johansson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Geza, Vadims
    Faculty of Physics and Mathematics, University of Latvia, Riga, Latvia.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Jakovics, Andris
    Faculty of Physics and Mathematics, University of Latvia, Riga, Latvia.
    Characteristics of flow and temperature distribution in a Ruthner process2010In: Proceedings of Modeling for Material Processing, 6th International Scientific Colloquium: Modelling for maerial processing, Rīga, September 16-17, 2010, University of Latvia Press, 2010, p. 317-322Conference paper (Refereed)
    Abstract [en]

    This study is devoted to CFD modelling of the gas flow and particle dynamics inside the reactor of a furnace used for regeneration of hydrochloric acid from iron chloride - a rest product from the pickling process in the steel industry. The understanding of the dynamics inside the reactor has shown to be of great importance in order to optimize the process. So far the process has been a black box, where only the inflow conditions are known together with the quality of the final product. In this work the gas flow is resolved together with the thermal distribution and the particle trajectory for the injected acid molecules.

    Download full text (pdf)
    fulltext
  • 25.
    Johansson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Simuleringar av dyspositionens inverkan på flöde och temperturdistribution i en ruthner process2011Conference paper (Other academic)
    Abstract [sv]

    Saltsyra (HCl) används inom stålindustrin för att beta järnoxider (Fe2O3) efter varmvalsning av plåt innan den förädlas i produktionslinan. Stora mängder HCl förbrukas, vilket både är kostsamt och miljöfarlig om den inte återvinns. Återvinningen sker oftast på stålverken med en metod som kallas Ruthner process. Den kan illustreras av en cylindrisk ugn med konisk nedre del, där det strax ovanför den koniska delen sitter naturgasbrännare tangentiellt till ugnen. Den förbrukade saltsyran, som består av vatten (H2O) och järnklorid (FeCl2), tillförs genom en till fyra dysor i toppen av ugnen. Återvinningen sker - något förenklat - genom att H2O först förångas från dropparna, därefter reagerar FeCl2 med syre (O2) och H2O och bildar HCl och Fe2O3. HCl återförs till betningsprocessen och Fe2O3 kan exempelvis säljas till elektronikindustrin.Denna studie syftar till att öka förståelsen av processen så att det i framtiden är möjligt att säkerställa god kvalité av restprodukten Fe2O3. Simuleringar görs i Ansys CFX med en tvåvägskopplad Euler/Lagrange-ansats där Eulerfasen består av gas och dropparna av förbrukad HCl är på Lagrangeform. Produkten från naturgasbrännarna ges som randvillkor till inloppet. I modellen är det första steget i återvinningsprocessen då droppar förångas implementerad. Även lyftkraft p.g.a. olika gastemperaturer, energiförluster genom väggar, och dragkraft på partiklar är implementerade i modellen. Som turbulensmodell används k-ε.Ur Figur 2 ses att både temperaturfördelning och hastighetsprofil förändras med olika dyspositioner. En korrelation mellan bilderna finns; i områden med låg temperatur är hastigheten riktad nedåt. Med dysan placerad 3,5 m från centrum förskjuts dock området för negativ vertikal hastighet bort från väggen. Detta beroende på att den varma gasen från brännare stiger längs väggen. De stora skillnaderna i temperaturfördelning är att dysposition 0.5 m från centrum ger en hög utloppstemperatur samt att dysposition 0.5 m och 3.5 m ger en högre temperatur i botten. Tendensen i hastighetsprofilen är lika för de tre fallen med dysan närmast väggen. När dysan placeras i mitten blir det ett kallras i centrum. För att få en klarare bild av processen krävs det även att partiklar analyseras samt att i framtiden även implementera kemiska reaktioner.

    Download full text (pdf)
    FULLTEXT01
  • 26.
    Johansson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gas and particle flow in a spray roaster2014In: Journal of Applied Fluid Mechanics, ISSN 1735-3572, E-ISSN 1735-3645, Vol. 7, no 2, p. 187-196Article in journal (Refereed)
    Abstract [en]

    In the steel industry, waste hydrochloric acid is produced through the process to pickle steel slabs for removal of corrosion. Regenerated hydrochloric acid is obtained by separating the chloride gas from the waste product through spray roasting. This process also produces a by-product in the form of iron oxide which is sold to different industries. The present study is a continuation of a study arising from the need to better understand the dynamics inside the regeneration reactor, which in turn will improve possibilities to optimize the regeneration process, which to date has been manually adjusted by trial and error. In this study the velocity and temperature distribution inside the reactor is numerically modelled together with the droplet motion through the reactor. The main objective is to investigate the influence of a changed spray nozzle position on the flow characteristics of the continuous and dispersed phase, and the relation between temperature and energy efficiency and the regeneration process. Numerical models of the type of flow present in the regeneration reactor are not represented to any major extent in the literature, making the present study relevant to the engineers and researchers active in the steel industry and the application in question.

  • 27.
    Jonsén, Pär
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.
    Westerberg, Lars-GöranLuleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.Larsson, SimonLuleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.Olsson, ErikLuleå University of Technology, Department of Engineering Sciences and Mathematics, Solid Mechanics.
    Svenska Mekanikdagar 20222022Conference proceedings (editor) (Refereed)
  • 28.
    Karami, Fatemeh
    et al.
    Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran.
    Nadooshan, Afshin Ahmadi
    Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Tadi Beni, Yaghoub
    Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran.
    Nano-fluid flow in a catheterized tapered artery: Consistent couple stress-theory and wall slip2019In: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 137, no 1, p. 327-342Article in journal (Refereed)
    Abstract [en]

    This study was conducted with the aim of investigating the Newtonian nanofluid flow in a catheterized tapered artery through using a completely consistent couple stress theory. In the process of carrying out this study, the slip condition at the arterial wall and the catheter, as well as, the permeability was taken into account. Further, the velocity, temperature, and concentration profiles were analytically modeled and the effect of the length scale on these profiles was well presented through the way it influences small-scale flows. The effect of the slip condition at the artery and catheter walls on the velocity was also investigated and revealed that any increase in the velocity leads to an increase in the slip velocity. Furthermore, the effect of other parameters such as the catheter diameter, shape, and height of the stenosis on these profiles was explored for all three artery geometries, i.e., diverging tapered artery, converging tapered artery, and non-tapered artery, respectively. The findings suggested that any increase in the catheter diameter and stenosis height can decrease the velocity and nanoparticle concentration profiles, while the temperature profile increases. It was also found that by increasing the stenosis shape parameter the velocity and concentration profiles increase and temperature decreases.

  • 29.
    Kluge, Jimmy Nils Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nyman, Tony
    SAAB Aerostructures, Linköping, Sweden.
    Modelling heat transfer inside an autoclave: Effect of radiation2016In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 35, no 14, p. 1126-1142Article in journal (Refereed)
    Abstract [en]

    In this work, computational fluid dynamics simulations are performed to predict the temperature distribution on a part during an autoclave run. Data from an experimental study are used as input to the simulations and also for comparison with the numerical results. A conjugate heat transfer approach was used for the simulations, where best agreement with experiments was obtained from the simulation that included thermal radiation and utilized an experimentally obtained velocity profile as inlet velocity. A yet more detailed inlet velocity profile and more advanced turbulent model could result in an even better agreement.

  • 30.
    Kluge, N. E. Jimmy
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Ljung, Anna-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nyman, Tony
    SAAB Aerostructures, Linköping, Sweden.
    An Experimental Study of Temperature Distribution in an Autoclave2016In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 35, no 7, p. 566-578Article in journal (Refereed)
    Abstract [en]

    In this work, the temperature distribution on an industrial mold tool is monitored during autoclave runs with three settings. In one of the settings, the temperature and pressure follow a scheme used in real moldings, while in the other two cases, the temperature is increased as fast as possible with and without an applied pressure. The temperature difference over the tool is relatively large and varies between 29℃ and 76℃ validating a detailed investigation of the temperature at different points. Two results of this are that positions on the up-stream side of the tool are heated faster than positions down-stream and the heating over the tool is symmetric while that within is asymmetric. Roughly estimated heat transfer coefficients reveal that the temperature ramping has no significant effect on the local heat transfer coefficients while the applied pressure more than doubled them. In addition flow field measurements with particle image velocimetry are performed, revealing a very slow flow near the roof of the autoclave and a velocity peak near the floor of it, indicating that the flow profile within the autoclave and variation in heat transfer coefficients should be considered in autoclave simulations.

  • 31.
    Kluge, NE Jimmy
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Olofsson, Kurt
    Swedish Institute of Composites, Swerea SICOMP AB, Piteå, Sweden.
    Compression moulding of sheet moulding compound: Modelling with computational fluid dynamics and validation2015In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 34, no 6, p. 479-492Article in journal (Refereed)
    Abstract [en]

    Compression moulding experiments of sheet moulding compound, visual observations of a vacuum test with prepregs and numerical models with two main approaches for computational fluid dynamics simulations of the mould filling phase are presented. One assumes that there are layers near the mould surfaces with much less viscosity and the other only use one viscosity model. The numerical experiments showed that the pressure could be accurately predicted with both approaches. The property necessary to predict correct pressure with altered mould closing velocities was that the bulk material had to obey shear-thinning effects. Preheating effects before compression were neglected, but altering the heating time until the prepreg was assumed to start flow had a significant effect. The experiments confirmed that the pressure is predominantly affected by the mould closing velocity. Regardless of the considered process settings, a first pressure top always appeared approximately at the logarithmic strain 0.25. A second top was associated with a slowdown of the press. The location of this was affected by the velocity and the vacuum, the latter indicating that vacuum assistance prevents a build-up of back pressure. Furthermore, heated prepreg above a critical temperature is observed to swell immediately as vacuum assistance is applied.

  • 32.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Grease Free Surface Flow on a Rotating Plate: a Combined Experimental and Analytical Analysis2014Conference paper (Refereed)
  • 33.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Green, Torbjörn M.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lugt, Piet M.
    SKF Engineering & Research Centre, Nieuwegein, The Netherlands.
    Baart, Pieter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements. SKF Engineering & Research Centre, Nieuwegein, The Netherlands.
    µPIV measurement of grease velocity profiles in channels with two different types of flow restrictions2012In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 54, p. 94-99Article in journal (Refereed)
    Abstract [en]

    Grease is commonly used to lubricate various machine components such as rolling bearings and seals. In this paper the flow of lubricating grease passing restrictions is described. Such flow occurs in rolling bearings during relubrication events where the grease is flowing in the transverse (axial) direction through the bearing and is hindered by guide rings, flanges et cetera, as well as in seals where transverse flow occurs, for example during so-called breathing caused by temperature fluctuations in the bearing. This study uses a 2D flow model geometry consisting of a wide channel with rectangular cross-section and two different types of restrictions to measure the grease velocity vector field, using the method of Micro Particle Image Velocimetry. In the case of a single restriction, the horizontal distance required for the velocity profile to fully develop is approximately the same as the height of the channel. In the corner before and after the restriction, the velocities are very low and part of the grease is stationary. For the channel with two flow restrictions, this effect is even more pronounced in the “pocket” between the restrictions. Clearly, a large part of the grease is not moving. This condition particularly applies to the cases with a low-pressure drop and where high consistency grease is used. In practice this means that grease is not replaced in such “corners” and that some aged/contaminated grease will remain in seal pockets.

  • 34.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Zhmud, Boris
    Applied Nano Surfaces.
    Rheology of Lubricating Grease2015In: Lube Magazine, ISSN 1744-5418, Vol. 126, p. 12-18Article in journal (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 35.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Green, Torbjörn
    Lundström, Staffan
    Lugt, Piet
    Baart, Pieter
    Measurements of grease flow in channels with restrictions using μPIV2010In: 14th Nordic Symposium on Tribology: NORDTRIB 2010 : Storforsen, Sweden, June 8-11, 2010, Luleå: Luleå tekniska universitet, 2010Conference paper (Refereed)
    Abstract [en]

    Grease is commonly used to lubricate various machine components such as rolling element bearings, open gears etc. Better understanding of the flow properties of grease will contribute to understanding the lubrication mechanism in bearings and flow in lubrication systems. In an earlier paper Micro Particle Image Velocimetry (μPIV) techniques were used to study the flow in a rectangular channel. The present paper is an extension of this work where restrictions were applied in such a channel, which creates a much more complex velocity field. The grease is seeded with fluorescent particles, which are illuminated by a double-pulsed laser. The test geometries that are used in this study are a channel with one flat restriction and one with two flow restrictions in a similar channel. The stationary grease mass-flow and the two dimensional velocity fields have been monitored for different pressure drops. For the channel with one flat restriction, the flow was measured to be symmetric at the inlet and outlet, and the distance for the flow to fully develop is comparable with the height of the channel; Slow motion was followed near the step corner at the inlet. For the channel with two flow restrictions, the vector profiles show that the maximum velocity appears at the restrictions; In-between the two restrictions, a part of the grease is not moving. This particularly applies to cases with low-pressure drop and where high consistency grease was used.

    Download full text (pdf)
    FULLTEXT01
  • 36.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Baart, Pieter
    SKF Engineering & Research Center, Nieuwegein.
    Lugt, Piet
    SKF Engineering & Research Center, Nieuwegein.
    Experimental study of free surface grease flow subjected to centrifugal forces2014Conference paper (Refereed)
    Abstract [en]

    In order to improve the understanding of grease flow in various applications such as gears, seals and rolling bearings, the free surface flow of different greases under different running conditions has been investigated. A rotating disc has been used to study grease flow as the grease was subjected to a centrifugal force. The grease flow and mass loss was measured for greases with different rheology on different surfaces and with surface textures. It is shown that the speed at which grease starts to move is mostly determined by grease type and yield stress, while the impact of the surface material and roughness is less pronounced. The mass loss is shown to be influenced both by the rheology of the grease and the surface material

    Download full text (pdf)
    FULLTEXT01
  • 37.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet
    SKF ERC.
    Baart, Pieter
    SKF ERC.
    Lubricating Grease Shear Flow and Boundary Layers in a Concentric Cylinder Configuration2015Conference paper (Refereed)
    Abstract [en]

    Grease is extensively used to lubricate various machine elements such as rolling bearings, seals, and gears. Understanding the flow dynamics of grease is relevant for the prediction of grease distribution for optimum lubrication and for the migration of wear and contaminant particles. In this study, grease flow is visualized using micro Particle Image Velocimetry (μPIV). The experimental setup includes a concentric cylinder configuration with a rotating shaft to simulate the grease flow in a double restriction seal geometry with two different grease pocket sizes. It is shown that the grease is partially yielded in the large grease pocket geometry and fully yielded in the small grease pocket. For the small grease pocket, it is shown that three distinct grease flow layers are present: a high shear rate region close to the stationary wall, a bulk flow layer, and a high shear rate boundary region near the rotating shaft. The grease shear thinning behavior and its wall slip effects have been identified. The μPIV experimental results have been compared with a numerical model for both the large and small gap size. It is shown that the flow is close to one-dimensional in the center of the small pocket. A one-dimensional analytical model based on the Herschel-Bulkley rheology model has been developed, showing good agreement with the measured velocity profiles in the small grease pocket. Furthermore, wall slip effects and shear banding are observed, where the latter imply that using the assumption of uniform shear in conventional concentric cylinder rheometers may result in erroneous rheological results.

  • 38.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lugt, Piet M.
    SKF Engineering and Research Centre, 3430 DT Nieuwegein, The Netherlands.
    Baart, Pieter
    SKF Engineering and Research Centre, 3430 DT Nieuwegein, The Netherlands.
    Lubricating grease shear flow and boundary layers in a concentric cylinder configuration2014In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 57, no 6, p. 1106-1115Article in journal (Refereed)
    Abstract [en]

    Grease is extensively used to lubricate various machine elements such as rolling bearings, seals, and gears. Understanding the flow dynamics of grease is relevant for the prediction of grease distribution for optimum lubrication and for the migration of wear and contaminant particles. In this study, grease flow is visualized using microparticle image velocimetry (μPIV). The experimental setup includes a concentric cylinder configuration with a rotating shaft to simulate the grease flow in a double restriction seal geometry with two different grease pocket sizes. It is shown that the grease is partially yielded in the large grease pocket geometry and fully yielded in the small grease pocket. For the small grease pocket, it is shown that three distinct grease flow layers are present: a high shear rate region close to the stationary wall, a bulk flow layer, and a high shear rate boundary region near the rotating shaft. The grease shear thinning behavior and its wall slip effects have been identified. The μPIV experimental results have been compared with a numerical model for both the large and small gap size. It is shown that the flow is close to one-dimensional in the center of the small pocket. A one-dimensional analytical model based on the Herschel-Bulkley rheology model has been developed, showing good agreement with the measured velocity profiles in the small grease pocket. Furthermore, wall slip effects and shear banding are observed, where the latter imply that using the assumption of uniform shear in conventional concentric cylinder rheometers may result in erroneous rheological results.

  • 39.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Design of test rig for visualizations of cylindrical shear and pressure driven Couette flow using μPIV2014Conference paper (Refereed)
    Abstract [en]

    Couette flow is often encountered in concentric cylinder application such as rheometers etc. Being able to visualize such flows is of interest both from a fundamental point of view to understand the dynamics of complex fluids, but also in specific applications such as lubricants flowing through seal geometries. In this study a concentric cylinder test rig has been designed to visualize Couette flow in both radial and axial direction using micro Particle Image Velocimetry. The rig allows for control of the flow motion; the rotating inner cylinder creates a peripheral flow and an applied pressure in the axial direction creates a pressure driven flow. Thus, a single flow direction or a combination of directions can be analyzed. To demonstrate the technique a flow of a non-Newtonian shear thinning fluid in the form of lubricating grease was investigated and discussed. It is found that it is possible to capture the yield behavior of the grease, with regions of fully and partially yielded flow visible. The influence of temperature creep flow is also presented. Grease with both high and low yield stress are measured and compared could be measured and compared in a pocket with variable size. Furthermore, non-homogeneous effects such as shear banding and wall slip can be visualized. The test rig has thus a high potential to investigate the influence of wall material and wettability between fluids and the housing on the flow and wall slip behavior as long as the fluid is optically transparent.

    Download full text (pdf)
    FULLTEXT01
  • 40.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Grease free surface flow on a rotating plate2014Conference paper (Refereed)
    Abstract [en]

    In order to improve the understanding of grease flow in various applications such as gears, seals and rolling element bearings, free surface flow of different greases under different running conditions has been investigated. A rotating disc has been used to study grease flow as the grease is subjected to a centrifugal force. The adhesion and mass loss was detected for greases with different rheology on different surfaces and surface textures. It is shown that the speed at which grease starts to move is mostly determined by grease type, yield stress and bleeding properties rather than surface material. Also, the surface adhesion is shown to be influenced both by the rheology of the grease and the surface material.

  • 41.
    Li, Jinxia
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Baart, Pieter
    SKF Engineering & Research Center, Nieuwegein.
    Lugt, Piet
    SKF Engineering & Research Center, Nieuwegein.
    Lubricating grease shear flow and boundary layers in a concentric cylinder configuration2013In: Proceedings of the 3rd International Tribology Symposium of IFoMM (International Federation for the Promotion of Mechanism and Machine Science), Luleå, March 19-21, 2013, 2013Conference paper (Refereed)
    Abstract [en]

    Grease is extensively used to lubricate various machine elements such as rollingbearings, seals, and gears. Understanding the flow dynamics of grease is relevant forthe prediction of the grease distribution for optimum lubrication and the migration ofwear- and contaminant particles. In this study grease flow is visualized using themethod of micro Particle Image Velocimetry; the experimental setup comprises aconcentric cylinder with rotating shaft to simulate the grease flow in a DoubleRestriction Seal (DRS) geometry with two different grease pocket heights. It is shownthat grease may be partially yielded in the large grease pocket geometry and fullyyielded in the small grease pocket geometry. For the small grease pocket geometry, itis shown that three distinct grease flow layers are present: a high shear rate regionclose to the stationary wall, a bulk flow layer, and a high shear rate boundary regionnear the rotating shaft. The grease shear thinning behaviour and its wall slip effectshave been detected and discussed.

    Download full text (pdf)
    FULLTEXT01
  • 42.
    Likitha, Sai Siddanathi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Akerstedt, Hans O.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Wiinikka, H.
    RISE Energy Technology Center, Industrigatan 1, Piteå, Sweden.
    Sepman, A.
    RISE Energy Technology Center, Industrigatan 1, Piteå, Sweden.
    Computational and Experimental Study of Flow Properties in a Plasma Torch2022In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper (Refereed)
  • 43.
    Olsson, Jimmy
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lundström, T. Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Nyman, Tonny
    Saab Aeronautics, SE-582 54 Linköping, SWEDEN.
    Flow and heat transfer inside an autoclave2012In: Proceedings of the 11th International Conference on Flow Processing in Composite Materials, 2012Conference paper (Other academic)
    Abstract [en]

    This work, that involves both experiments and numerical simulations, concerns autoclave molding. An autoclave is basically a pressure vessel, where the entrapped and often highly compressed gas is heated and circulated in order to heat the components that have been placed inside the vessel. In the autoclaveprocess, the desirable state would be that an even and optimal temperature existed in the whole part that is manufactured. Unfortunately, this is not always the case. All in all we need to get a better understanding of the flow inside an autoclave and the convective heat transfer from the heated gas to the composite components. In this work we have therefore investigated the flow behavior by performing qualitative measurements with particle image velocimetry inside an autoclave. The concept is to dope the gas within the autoclave with smoke and illuminate the smoke with a thin sheet of laser light. Captured images of the moving smoke are then cross correlated to give velocity fields. We have also investigated the heat transfer to the tool by measuring the temperature at multiple locations during heating. The obtained velocity field is used to produce inlet condition for the simulations, performed with Computational Fluid Dynamics, which subsequently are compared with the experimentally obtained tool temperature. The simulation technique may then be used to optimize both the tools, and the actual location of the tools inside the autoclave in order to improve quality and reduce costs.

  • 44.
    Sarkar, Chiranjit
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Höglund, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Lundström, Staffan T.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Numerical simulations of lubricating grease flow in a rectangular channel with and without restrictions2018In: Tribology Transactions, ISSN 1040-2004, E-ISSN 1547-397X, Vol. 61, no 1, p. 144-156Article in journal (Refereed)
    Abstract [en]

    This article presents numerical simulations of the laminar flow of lubricating greases in a channel with rectangular cross section. Three greases with different consistencies (NLGI grades 00, 1, and 2) have been considered in three different configurations composed of a rectangular channel without restrictions, one rectangular step restriction, and one double-lip restriction. The driving pressure drop over the channel spans from 30 to 250 kPa. The grease rheology is described by the Herschel-Bulkley rheology model, and both the numerical code and rheology model have been validated with analytical solutions and flow measurements using micro-particle image velocimetry.

  • 45.
    Schillings, Audrey
    et al.
    Department of Physics, Umeå University, Umeå, Sweden.
    Gunell, H.
    Umeå University, Umeå, Sweden. Belgian Institute for Space Aeronomy, Brussels, Belgium.
    Nilsson, H.
    Institutet för Rymdfysik, Kiruna, Sweden.
    De Spiegeleer, A.
    Department of Physics, Umeå University, Umeå, Sweden.
    Ebihara, Y.
    Research Institute for Sustainable Humanosphere, Kyoto University, Japan.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Yamauchi, M.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Slapak, R.
    EISCAT Scientific Association, Kiruna, Sweden.
    The fate of O+ ions observed in the plasma mantle: particle tracing modelling and Cluster observations2020Conference paper (Refereed)
    Abstract [en]

    The atmospheric evolution on geological timescales is partly given by the atmospheric escape. This escape includes ion escape and particularly O+ ions. How much O+ ions escape from the Earth is the main focus of this study. Using the Tsyganenko and Weimer models to represent the magnetic and electric fields respectively, we traced 26200 O+ ions trajectories forward in time and studied their final positions in the Earth’s environment. Starting in the plasma mantle, the initial positions, thermal and parallel bulk velocities of O+ ions are taken from the European Cluster observations between 2001 and 2007. Most (98%) of the ions observed in the plasma mantle escape the Earth’s magnetosphere, with 20% of them directly through the dayside magnetopause.  An interesting feature of the 80% escaping ions left is that very few reach the distant tail, they rather escape through the nightside magnetopause. Finally, no significant correlation was found between magnetospheric disturbed conditions and the final positions of the traced O+ ions.

  • 46.
    Schillings, Audrey
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna, Sweden.
    Gunell, Herbert
    Department of Physics, Umeå University, Umeå, Sweden; Belgian Institute for Space Aeronomy, Brussels, Belgium.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna, Sweden.
    De Spiegeleer, Alexandre
    Department of Physics, Umeå University, Umeå, Sweden.
    Ebihara, Yusuke
    Research Institute for Sustainable Humanosphere, Kyoto University, 611-0011, Gokasho, Uji, Kyoto, Japan.
    Westerberg, Lars Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Yamauchi, Masatoshi
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Slapak, Rikard
    EISCAT Scientific Association, Kiruna, Sweden.
    The fate of O+ ions observed in the plasma mantle: particle tracing modelling and cluster observations2020In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 38, no 3, p. 645-656Article in journal (Refereed)
    Abstract [en]

    Ion escape is of particular interest for studying the evolution of the atmosphere on geological timescales. Previously, using Cluster-CODIF data, we investigated the oxygen ion outflow from the plasma mantle for different solar wind conditions and geomagnetic activity. We found significant correlations between solar wind parameters, geomagnetic activity (Kp index), and the O+ outflow. From these studies, we suggested that O+ ions observed in the plasma mantle and cusp have enough energy and velocity to escape the magnetosphere and be lost into the solar wind or in the distant magnetotail. Thus, this study aims to investigate where the ions observed in the plasma mantle end up. In order to answer this question, we numerically calculate the trajectories of O+ ions using a tracing code to further test this assumption and determine the fate of the observed ions. Our code consists of a magnetic field model (Tsyganenko T96) and an ionospheric potential model (Weimer 2001) in which particles initiated in the plasma mantle region are launched and traced forward in time. We analysed 131 observations of plasma mantle events in Cluster data between 2001 and 2007, and for each event 200 O+ particles were launched with an initial thermal and parallel bulk velocity corresponding to the velocities observed by Cluster. After the tracing, we found that 98 % of the particles are lost into the solar wind or in the distant tail. Out of these 98 %, 20 % escape via the dayside magnetosphere.

    Download full text (pdf)
    fulltext
  • 47.
    Schillings, Audrey
    et al.
    Department of Physics, Umeå University, Umeå, Sweden.
    Nilsson, H.
    Institutet för Rymdfysik, Kiruna, Sweden.
    Slapak, R.
    EISCAT Scientific Association, Kiruna, Sweden.
    Yamauchi, M.
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Earth’s O+ Outflow and Escape during Various Solar Wind Conditions2020Conference paper (Refereed)
    Abstract [en]

    Ion outflow at Earth is studied since several decades and is important for the global atmospheric evolution. Over the years, spacecraft and technology improved leading to new studies and breakthrough in the field. With different mechanisms to gain energy and velocity such as field-aligned acceleration, centrifugal acceleration and transversal heating, a large amount of ions becomes gravitationally untrapped above the ionosphere. While some of these ions may enter the plasma sheet and partially be redirected towards Earth, majority of these ions reaches the high-latitude boundary region, such as the plasma mantle and are lost into the solar wind. We examined this phenomenon using Cluster European Spacecraft that covers these high-latitude regions. Here, we studied the influence of solar wind conditions on O+ outflow and escape during 7 years of observations (2001 to 2007). We found that O+ outflow is exponentially correlated with enhanced geomagnetic activity (Kp index) as well as with solar wind dynamic pressure and IMF. Under undisturbed magnetospheric conditions, the O+ outflow is typically 1012.5 m-2s-1 while it reaches 1014 m-2s-1 during major geomagnetic storms. Additionally, tracing (forward in time) about 25000 O+ ions initially observed in the plasma mantle showed that 98% of these ions escape directly through the magnetopause whereas only a few escape through the distant tail. In summary, the more disturbed the magnetosphere is, the more ion outflow and escape is observed.

  • 48.
    Schillings, Audrey
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instiutet for rymdfysik, Kiruna, Sweden.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Instiutet for rymdfysik, Kiruna, Sweden.
    Slapak, Rikard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Yamauchi, M
    Swedish Institute of Space Physics, Kiruna, Sweden.
    Westerberg, Lars Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Relative outflow enhancements during major geomagnetic storms: Cluster observations2017In: Annales Geophysicae, ISSN 0992-7689, E-ISSN 1432-0576, Vol. 5, no 6, p. 1341-1352Article in journal (Refereed)
    Abstract [en]

    The rate of ion outflow from the polar ionosphere is known to vary by orders of magnitude, depending on the geomagnetic activity. However, the upper limit of the outflow rate during the largest geomagnetic storms is not well constrained due to poor spatial coverage during storm events. In this paper, we analyse six major geomagnetic storms between 2001 and 2004 using Cluster data. The six major storms fulfil the criteria of Dst 100 nT or Kp 7C. Since the shape of the magnetospheric regions (plasma mantle, lobe and inner magnetosphere) are distorted during large magnetic storms, we use both plasma beta and ion characteristics to define a spatial box where the upward OC flux scaled to an ionospheric reference altitude for the extreme event is observed. The relative enhancement of the scaled outflow in the spatial boxes as compared to the data from the full year when the storm occurred is estimated. Only OC data were used because HC may have a solar wind origin. The storm time data for most cases showed up as a clearly distinguishable separate peak in the distribution toward the largest fluxes observed. The relative enhancement in the outflow region during storm time is 1 to 2 orders of magnitude higher compared to less disturbed time. The largest relative scaled outflow enhancement is 83 (7 November 2004) and the highest scaled OC outflow observed is 2 1014 m2 s1 (29 October 2003).

  • 49.
    Schillings, Audrey
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Slapak, Rikard
    EISCAT Scientifc Association, Kiruna.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Yamauchi, Masatoshi
    Swedish Institute of Space Physics, Kiruna.
    Dandouras, Iannis
    IRAP, Université de Toulouse, CNRS, UPS, CNES, Toulouse, France.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Earth atmospheric loss through the plasma mantle and its dependence on solar wind parameters2019In: Earth Planets and Space, ISSN 1343-8832, E-ISSN 1880-5981, Vol. 71, no 70Article in journal (Refereed)
    Abstract [en]

    Atmospheric loss and ion outfow play an important role in the magnetospheric dynamics and in the evolution of the atmosphere on geological timescales—an evolution which is also dependent on the solar activity. In this paper, we investigate the total O+ outfow [s−1 ] through the plasma mantle and its dependency on several solar wind param‑ eters. The oxygen ion data come from the CODIF instrument on board the spacecraft Cluster 4 and solar wind data from the OMNIWeb database for a period of 5 years (2001–2005). We study the distribution of the dynamic pressure and the interplanetary magnetic feld for time periods with available O+ observations in the plasma mantle. We then divided the data into suitably sized intervals. Additionally, we analyse the extreme ultraviolet radiation (EUV) data from the TIMED mission. We estimate the O+ escape rate [ions/s] as a function of the solar wind dynamic pressure, the interplanetary magnetic feld (IMF) and EUV. Our analysis shows that the O+ escape rate in the plasma mantle increases with increased solar wind dynamic pressure. Consistently, it was found that the southward IMF also plays an important role in the O+ escape rate in contrast to the EUV fux which does not have a signifcant infuence for the plasma mantle region. Finally, the relation between the O+ escape rate and the solar wind energy transferred into the magnetosphere shows a nonlinear response. The O+ escape rate starts increasing with an energy input of approxi‑ mately 1011W.

  • 50.
    Schillings, Audrey
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics (IRF), Kiruna, Sweden .
    Slapak, Rikard
    EISCAT Scientific Association, Kiruna.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics (IRF), Kiruna.
    Yamauchi, Masatoshi
    Swedish Institute of Space Physics (IRF), Kiruna.
    Dandouras, Iannis
    Université de Toulouse, CNRS, UPS, CNES, Toulouse, France.
    Westerberg, Lars-Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Earth atmospheric loss through the plasma mantle and its dependence onsolar wind parameters2019Conference paper (Refereed)
    Download full text (pdf)
    fulltext
12 1 - 50 of 100
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf