Change search
Refine search result
1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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.
    Baidar, Binaya
    et al.
    Department of Mechanical Engineering, Kathmandu University.
    Koirala, Ravi
    Department of Mechanical Engineering, Kathmandu University.
    Neopane, Hari P.
    Department of Mechanical Engineering, Kathmandu University.
    Shrestha, Mahabharat V.
    Resource Management and Rural Empowerment Centre (REMREC), National Rural and Renewable Energy Programme/Alternative Energy Promotion Centre (AEPC).
    Thapa, Bhola
    Department of Mechanical Engineering, Kathmandu University.
    Strategic rehabilitation of the earthquake affected microhydropower plants in Nepal2016In: IOP Conference Series: Earth and Environment, ISSN 1755-1307, E-ISSN 1755-1315, Vol. 49, no 10, article id 102003Article in journal (Refereed)
    Abstract [en]

    Most people in the rural areas of Nepal rely on Micro-hydro Power Plants (MHPs) for their energy sources. With around four decade experiences in design and development of MHPs, Nepalese techno-entrepreneurs have gained wider reputation in the South Asian region and the beyond. However with the lack of competences in developing Francis turbines, majority of the MHPs are equipped with either Pelton of Cross Flow turbine, even though Francis units are suitable. With the devastating earthquake of a 7.6 magnitude that struck in the Gorkha district on Saturday, 25 April 2015, about 76 km northwest of the capital city Kathmandu, and the aftershocks followed claimed more than 8000 lives. It did not leave hydropower plants either. Many big plants have been affected and hundreds of MHPs were damaged, needing short to long term rehabilitation. The preliminary assessment of the 61 affected MHPs in the 6 earthquake affected districts shows more than 50% sites are suitable for Francis turbine. Hence the strategic rehabilitation plan has been developed in the present paper for the affected plants considering issues like geographical shift, dislocation of people and also with the focus on replacing the old turbine with Francis turbine in the suitable sites. The similar strategy can also be implemented in other developing countries with such situations.

  • 2.
    Bergan, Carl
    et al.
    Waterpower Laboratory, Norwegian University of Science and Technology.
    Goyal, Rahul
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics. Indian Institute of Technology Roorkee.
    Cervantes, Michel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Dalhaug, Ole Gunnar
    Waterpower Laboratory, Norwegian University of Science and Technology.
    Experimental Investigation of a High Head Model Francis Turbine During Steady-State Operation at Off-Design Conditions2016In: IOP Conference Series: Earth and Environment, ISSN 1755-1307, E-ISSN 1755-1315, Vol. 49, no 8, article id 062018Article in journal (Refereed)
    Abstract [en]

    Francis-99 is a set of workshops aiming to determine the state of the art of high head Francis turbine simulations (flow and structure) under steady and transient operating conditions as well as promote their development and knowledge dissemination openly. The first workshop (Trondheim, 2014) focused on steady state conditions. Some concerns were raised regarding uncertainty in the measurements, mainly that there was no clear vortex rope at the Part Load (PL) condition, and that the flow exhibited relatively large asymmetry. The present paper addresses these concerns in order to ensure the quality of the data presented in further workshops. To answer some of these questions, a new set of measurements were performed on the Francis 99 model at Waterpower Laboratory at the Norwegian University of Science and Technology (NTNU). In addition to PL, two other operating conditions were considered, for further use in transient measurements, Best Efficiency (BEP) and High Load (HL). The experiments were carried out at a head of 12 m, with a runner rotational speed of 333 revolutions per minute (rpm). The guide vane opening angle were 6.72 degrees, 9.84 degrees and 12.43 degrees for PL, BEP and HL, respectively. The part load condition has been changed from the first workshop, to ensure a fully developed Rotating Vortex Rope (RVR). The velocity and pressure measurements were carried out in the draft tube cone using 2D PIV and six pressure sensors, respectively. The new PL condition shows a fully developed rotating vortex rope (RVR) in both the frequency analysis and in the phase resolved data. In addition, the measurements confirm an asymmetric flow leaving the runner, as was a concern in the first Francis-99 workshop. This asymmetry was detected at both design and off-design conditions, with a stronger effect during off design.

  • 3.
    Cupillard, Samuel
    et al.
    Hydro-Québec Research Institute, Varennes, Québec, Canada.
    Aidanpää, Jan-Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Influence of the thrust bearing on the natural frequencies of a72-MW hydropower rotor2016In: IOP Conference Series: Earth and Environment, ISSN 1755-1307, E-ISSN 1755-1315, Vol. 49, no 8, article id 082024Article in journal (Refereed)
    Abstract [en]

    The thrust bearing is an essential element of a hydropower machine. Not only does it carry the total axial load but it also introduces stiffness and damping properties in the system. The focus of this study is on the influence of the thrust bearing on the lateral vibrations of the shaft of a 72-MW propeller turbine. The thrust bearing has a non-conventional design with a large radius and two rows of thrust pads. A numerical model is developed to estimate natural frequencies. Numerical results are analyzed and related to experimental measurements of a runaway test. The results show the need to include the thrust bearing in the model. In fact, the vibration modes are substantially increased towards higher frequencies with the added properties from the thrust bearing. The second mode of vibration has been identified in the experimental measurements. Its frequency and mode shape compare well with numerical results.

  • 4.
    Goyal, Rahul
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics. Indian Institute of Technology Roorkee.
    Bergan, Carl
    Waterpower Laboratory, Norwegian University of Science and Technology.
    Cervantes, Michel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Gandhi, Bhupendra K.
    Indian Institute of Technology Roorkee.
    Dalhaug, Ole Gunnar
    Waterpower Laboratory, Norwegian University of Science and Technology.
    Experimental investigation on a high head model Francis turbine during load rejection2016In: IOP Conference Series: Earth and Environment, ISSN 1755-1307, E-ISSN 1755-1315, Vol. 49, no 8, article id 082004Article in journal (Refereed)
    Abstract [en]

    Francis-99 is a set of workshop aiming to determine the state of the art of high head model Francis turbine simulations (flow and structure) under steady and transient operating conditions as well as to promote their development and knowledge dissemination openly. The first workshop (Trondheim, 2014) was concerned with steady state operation. The second workshop will focus on transient operations such as load variation and start-stop. In the present work, 2-D particle image velocimetry (PIV) with synchronized pressure measurements performed in the draft tube cone of the Francis-99 test case during load rejection is presented. Pressure sensors were mounted in the vaneless space and draft tube cone to estimate the instantaneous pressure fluctuations while operating the turbine from the best efficiency point (9.8°) to part load (6.7°) with the presence of a rotating vortex rope (RVR). The time-resolved velocity and pressure data are presented in this paper showing the transition in the turbine from one state to another

  • 5.
    Maddahian, R.
    et al.
    Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, I.R. Iran.
    Cervantes, Michel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Sotoudeh, N.
    Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, I.R. Iran.
    Numerical Investigation of the Flow Structure in a Kaplan Draft Tube at Part Load2016In: IOP Conference Series: Earth and Environment, ISSN 1755-1307, E-ISSN 1755-1315, Vol. 49, no 2, article id 022008Article in journal (Refereed)
    Abstract [en]

    This research presents numerical simulation of the unsteady flow field inside the draft tube of a Kaplan turbine at part load condition. Due to curvature of streamlines, the ordinary two-equations turbulence models fail to predict the flow features. Therefore, a modification of the Shear Stress Transport (SST-SAS) model is utilized to approximate the turbulent stresses. A guide vane, complete runner and draft tube are considered to insure the real boundary conditions at the draft tube inlet. The outlet boundary is assumed to discharge into the atmosphere. The obtained pressure fluctuations inside the draft tube are in good agreement with available experimental data. In order to further investigate the RVR formation and its movement, the λ2 criterion, relating the position of the vortex core and strength to the second largest Eigen value of the velocity gradient tensor, is employed. The method used for vortex identification shows the flow structure and vortex motion inside the draft tube accurately.

1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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