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Andersson, Anders G.ORCID iD iconorcid.org/0000-0001-9789-6293
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Publications (10 of 33) Show all publications
Misiulia, D., Antonyuk, S., Andersson, A. G. & Lundström, S. (2019). High-efficiency industrial cyclone separator: A CFD study. Powder Technology
Open this publication in new window or tab >>High-efficiency industrial cyclone separator: A CFD study
2019 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

The flow within an industrial scroll-inlet high-efficiency cyclone separator has been studied using RSM and LES simulations. Of particular interest is the effect of the gas outlet configuration, i.e. outlet scroll and radial bend, on the flow pattern, pressure drop and cyclone efficiency. A surprising phenomenon is that the inner vortex splits into two vortices for the cyclone with a conventional outlet pipe while if the cyclone is equipped with an outlet scroll or radial bend there is no split. The outlet scroll and radial bend increase the pressure losses by 5.1% and 6.4%, respectively. These installations, moreover, significantly destabilize the pressure losses and the amplitude of instantaneous pressure drop oscillations increases from 0.65% to 16.2% and 33.96%, respectively. The investigated outlet scroll and radial bend have practically no effects on the cyclone efficiency since the flow in the main separation zone is not affected by the gas outlet configuration.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Cyclone separator, Computational fluid dynamics, Vortex breakdown, Pressure drop, Collection efficiency
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-76944 (URN)10.1016/j.powtec.2019.10.064 (DOI)
Available from: 2019-11-28 Created: 2019-11-28 Last updated: 2019-11-28
Bin Asad, S. M., Lundström, S., Andersson, A. G., Hellström, J. G. & Leonardsson, K. (2019). Wall shear stress measurement on curve objects with PIV in connection to benthic fauna in regulated rivers. Water, 11(4), Article ID 650.
Open this publication in new window or tab >>Wall shear stress measurement on curve objects with PIV in connection to benthic fauna in regulated rivers
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2019 (English)In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, no 4, article id 650Article in journal (Refereed) Published
Abstract [en]

The flow characteristics in the vicinity of a set of half-cylinders of different sizes simulating benthic objects were studied experimentally using particle image velocimetry (PIV). The cylinders were mounted on the bottom of an open channel, and the influence of the flow speed on the distribution of the shear stress along the bottom geometry was investigated. Of special interest was how the shear stress changes close to the wall as a function of the flow speed and cylinder arrangement. It was found that the shear stress varies significantly as a function of position. This implies habitat heterogeneity allowing benthic invertebrates with different shear stress tolerance exists when the bottom consists of differently sized stones. It was also shown that direct measurements of near wall velocity gradients are necessary to accurately calculate the wall shear stress for more complex geometries.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
shear stress, PIV, benthic fauna, river, stones
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-74913 (URN)10.3390/w11040650 (DOI)000473105700020 ()2-s2.0-85065032227 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-24 (johcin)

Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-08-16Bibliographically approved
Andersson, L. R., Larsson, S., Hellström, J. G., Andreasson, P., Andersson, A. G. & Lundström, S. (2018). Characterization of Flow Structures Induced by Highly Rough Surface Using Particle Image Velocimetry, Proper Orthogonal Decomposition and Velocity Correlations. Engineering, 10, 399-416
Open this publication in new window or tab >>Characterization of Flow Structures Induced by Highly Rough Surface Using Particle Image Velocimetry, Proper Orthogonal Decomposition and Velocity Correlations
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2018 (English)In: Engineering, ISSN 1947-3931, Vol. 10, p. 399-416Article in journal (Refereed) Published
Abstract [en]

High Reynolds number flow inside a channel of rectangular cross section is examined using Particle Image Velocimetry. One wall of the channel has been replaced with a surface of a roughness representative to that of real hydropower tunnels, i.e. a random terrain with roughness dimensions typically in the range of ≈10% - 20% of the channels hydraulic radius. The rest of the channel walls can be considered smooth. The rough surface was captured from an existing blasted rock tunnel using high resolution laser scanning and scaled to 1:10. For quantification of the size of the largest flow structures, integral length scales are derived from the auto-correlation functions of the temporally averaged velocity. Additionally, Proper Orthogonal Decomposition (POD) and higher-order statistics are applied to the instantaneous snapshots of the velocity fluctuations. The results show a high spatial heterogeneity of the velocity and other flow characteristics in vicinity of the rough surface, putting outer similarity treatment into jeopardy. Roughness effects are not confined to the vicinity of the rough surface but can be seen in the outer flow throughout the channel, indicating a different behavior than postulated by Townsend’s similarity hypothesis. The effects on the flow structures vary depending on the shape and size of the roughness elements leading to a high spatial dependence of the flow above the rough surface. Hence, any spatial averaging, e.g. assuming a characteristic sand grain roughness factor, for determining local flow parameters becomes less applicable in this case.

Place, publisher, year, edition, pages
Scientific Research Publishing, 2018
Keywords
CFD, Validation, Hydraulic Roughness, PIV, Hydropower
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-71097 (URN)10.4236/eng.2018.107028 (DOI)
Available from: 2018-10-04 Created: 2018-10-04 Last updated: 2019-08-12Bibliographically approved
Knoepp, F., Wahl, J., Andersson, A. G., Borg, J., Weissmann, N. & Ramser, K. (2018). Development of a Gas-Tight Microfluidic System for Raman Sensing of Single Pulmonary Arterial Smooth Muscle Cells Under Normoxic/Hypoxic Conditions. Sensors, 10, Article ID 3238.
Open this publication in new window or tab >>Development of a Gas-Tight Microfluidic System for Raman Sensing of Single Pulmonary Arterial Smooth Muscle Cells Under Normoxic/Hypoxic Conditions
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2018 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 10, article id 3238Article in journal (Refereed) Published
Abstract [en]

Acute hypoxia changes the redox-state of pulmonary arterial smooth muscle cells (PASMCs). This might influence the activity of redox-sensitive voltage-gated K⁺-channels (Kv-channels) whose inhibition initiates hypoxic pulmonary vasoconstriction (HPV). However, the molecular mechanism of how hypoxia-or the subsequent change in the cellular redox-state-inhibits Kv-channels remains elusive. For this purpose, a new multifunctional gas-tight microfluidic system was developed enabling simultaneous single-cell Raman spectroscopic studies (to sense the redox-state under normoxic/hypoxic conditions) and patch-clamp experiments (to study the Kv-channel activity). The performance of the system was tested by optically recording the O₂-content and taking Raman spectra on murine PASMCs under normoxic/hypoxic conditions or in the presence of H₂O₂. Oxygen sensing showed that hypoxic levels in the gas-tight microfluidic system were achieved faster, more stable and significantly lower compared to a conventional open system (1.6 ± 0.2%, respectively 6.7 ± 0.7%, n = 6, p < 0.001). Raman spectra revealed that the redistribution of biomarkers (cytochromes, FeS, myoglobin and NADH) under hypoxic/normoxic conditions were improved in the gas-tight microfluidic system (p-values from 0.00% to 16.30%) compared to the open system (p-value from 0.01% to 98.42%). In conclusion, the new redox sensor holds promise for future experiments that may elucidate the role of Kv-channels during HPV.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2018
Keywords
Raman spectroscopy, hypoxia, microfluidic system, redox reactions on single cell level
National Category
Applied Mechanics Fluid Mechanics and Acoustics
Research subject
Experimental Mechanics; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-71090 (URN)10.3390/s18103238 (DOI)000448661500066 ()30261634 (PubMedID)2-s2.0-85054841733 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-03 (svasva)

Available from: 2018-10-03 Created: 2018-10-03 Last updated: 2019-04-24Bibliographically approved
Misiulia, D., Antonyuk, S., Andersson, A. G. & Lundström, T. S. (2018). Effects of deswirler position and its centre body shape as well as vortex finder extension downstream on cyclone performance. Powder Technology, 336, 45-56
Open this publication in new window or tab >>Effects of deswirler position and its centre body shape as well as vortex finder extension downstream on cyclone performance
2018 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 336, p. 45-56Article in journal (Refereed) Published
Abstract [en]

The performance of a cyclone is studied when changing the position of the deswirler in the vortex finder, its centre body shape and a downstream vortex finder extension. This is done with simulations applying a Reynolds stress model for the turbulence. An extension of the vortex finder (from 2.64 dvf to 6.8 dvf) has almost no effect on cyclone pressure drop or collection efficiency. Moreover, the extension does not affect the pressure losses in the vortex finder. The closer the deswirler is installed to the vortex finder inlet the more significant is its effects on cyclone performance. A streamlined ellipsoidal shape of the deswirler centre body is preferable to a cylindrical one since it leads to lower pressure losses. Installation of the deswirler with a streamlined ellipsoidal centre body 2.64 diameters downstream the vortex finder inlet reduces pressure losses in the vortex finder by 74% as compared to a standard set-up. This leads to a 32% reduction in total pressure drop without deteriorating the separation capability of the cyclone.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-68895 (URN)10.1016/j.powtec.2018.05.034 (DOI)000441491300004 ()2-s2.0-85048500045 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-25 (andbra)

Available from: 2018-05-24 Created: 2018-05-24 Last updated: 2018-08-30Bibliographically approved
Misiulia, D., Andersson, A. G. & Lundström, S. (2017). Effects of the inlet angle on the collection efficiency of a cyclone with helical-roof inlet. Powder Technology, 305, 48-55
Open this publication in new window or tab >>Effects of the inlet angle on the collection efficiency of a cyclone with helical-roof inlet
2017 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 305, p. 48-55Article in journal (Refereed) Published
Abstract [en]

The effects of inlet angle on the collection efficiency of a cyclone with helical-roof inlet have been computationally investigated using Large Eddy Simulations with the dynamic Smagorinsky-Lilly subgrid-scale model for five different inlet angles (7°, 11°, 15°, 20° and 25°). Forty thousand individual particles were tracked through the unsteady flow field using the Lagrangian approach. In order to reveal the collection efficiency of a cyclone with helical-roof inlet properly, simulation time should not be < 3.5 times the average flow residence time. Particles which diameter is close to the cyclone cut size have the longest residence times while particles of 10–25 μm in diameter have the shortest. Based on the simulations, expressions for the cut size and Euler number normalized with the mean axial velocity in a cyclone with helical-roof inlet of different inlet angles are derived. The results show that, increasing the inlet angle increases the cyclone cut size and as a result reduces cyclone collection efficiency. At the same time, it decreases the cyclone pressure drop coefficient (Euler number) leading to lower pressure losses. For most cases where high separation efficiency at moderate pressure drop is required the optimum inlet angle is in the range 10–15°.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-59743 (URN)10.1016/j.powtec.2016.09.050 (DOI)000390732000006 ()2-s2.0-84989182792 (Scopus ID)
Note

Validerad; 2016; Nivå 2; 2016-10-14 (andbra)

Available from: 2016-10-14 Created: 2016-10-14 Last updated: 2018-09-13Bibliographically approved
Bin Asad, S. M., Lundström, S. & Andersson, A. G. (2017). Experimental study of the flow past submerged half-cylinders. Paper presented at 7th BSME International Conference on Thermal Engineering, Dhaka, Bangladesh, 22–24 December, 2016. AIP Conference Proceedings, 1851, Article ID 020001.
Open this publication in new window or tab >>Experimental study of the flow past submerged half-cylinders
2017 (English)In: AIP Conference Proceedings, ISSN 0094-243X, E-ISSN 1551-7616, Vol. 1851, article id 020001Article in journal (Refereed) Published
Abstract [en]

This investigation studies the details of the flow behind and over two identical semicircular cylinderspositioned in tandem. Laser Doppler Velocimetry (LDV) measurements are carried out in a laboratory waterflume using two different gap ratios (Sp/d = 1 and Sp/d = 0.5; where Sp indicates distance between the cylindersand d indicates cylinder diameter) under two different flow situations. These LDV measurement are used toderive velocities, formation length and Power spectral density for the various flow conditions. Flowvisualizations are also added in this investigation. The results indicate that the flow is significantly affected dueto gap ratios.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2017
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-64318 (URN)10.1063/1.4984630 (DOI)000412828600001 ()2-s2.0-85022041470 (Scopus ID)
Conference
7th BSME International Conference on Thermal Engineering, Dhaka, Bangladesh, 22–24 December, 2016
Note

2017-06-21 (andbra);Konferensartikel i tidskrift

Available from: 2017-06-21 Created: 2017-06-21 Last updated: 2019-04-03Bibliographically approved
Misiulia, D., Elsayed, K. & Andersson, A. G. (2017). Geometry optimization of a deswirler for cyclone separator in terms of pressure drop using CFD and artificial neural network. Separation and Purification Technology, 185, 10-23
Open this publication in new window or tab >>Geometry optimization of a deswirler for cyclone separator in terms of pressure drop using CFD and artificial neural network
2017 (English)In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 185, p. 10-23Article in journal (Refereed) Published
Abstract [en]

Four main geometrical parameters of a deswirler (core diameter, number of vanes, height of vanes and leading edge angle) for cyclone separators have been optimized using CFD and artificial neural network. The results indicated that the most significant geometrical parameters of the deswirler are the number of vanes, the vane angle and the vane height. A new optimized deswirler geometry was obtained using the genetic algorithms and its effects on the flow field, pressure losses and cyclone collection efficiency were numerically investigated. The deswirler positively affects the flow field within a cyclone. It dramatically reduces tangential velocities in the vortex finder and only slightly (by 4.5%) decreases maximum tangential velocities in the separation zone. The deswirler also reduces the length of the inner vortex, redistributes uniformly axial velocities at the vortex finder outlet and prevents backward flow. Additionally, the deswirler converts the dynamic energy of the swirling flow into pressure and allows pressure recovery. It reduces pressure losses in the vortex finder by 95.67% that leads to 43.17% reduction in total pressure drop and slightly decreases the separation efficiency for some particle diameters, increasing the cyclone cut size from 1.5 to 1.72 μm.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-63302 (URN)10.1016/j.seppur.2017.05.025 (DOI)000404310900002 ()2-s2.0-85019371517 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-05-29 (rokbeg)

Available from: 2017-05-10 Created: 2017-05-10 Last updated: 2018-07-10Bibliographically approved
Misiulia, D., Andersson, A. G. & Lundström, S. (2017). Large Eddy Simulation Investigation of an Industrial Cyclone Separator Fitted with a Pressure Recovery Deswirler. Chemical Engineering & Technology, 40(4), 709-718
Open this publication in new window or tab >>Large Eddy Simulation Investigation of an Industrial Cyclone Separator Fitted with a Pressure Recovery Deswirler
2017 (English)In: Chemical Engineering & Technology, ISSN 0930-7516, E-ISSN 1521-4125, Vol. 40, no 4, p. 709-718Article in journal (Refereed) Published
Abstract [en]

A cyclone fitted with a deswirler of original design has been investigated by means of large eddy simulation. Installation of the deswirler reduces significantly the positive static pressure near the wall as well as the negative static pressure in the central region. It also decreases the maximum tangential velocities in the main separation zone. The deswirler enables a substantial reduction of the backward flow at the gas outlet and a more uniform distribution of the axial velocities at the gas outlet. It also considerably reduces pressure losses in the vortex finder lowering the cyclone pressure drop by almost about one third but it deteriorates the collection efficiency of particles with diameters of less than 8 µm, thus increasing the cut size.

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-62509 (URN)10.1002/ceat.201600505 (DOI)000397575600011 ()2-s2.0-85015181315 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-03-27 (rokbeg)

Available from: 2017-03-15 Created: 2017-03-15 Last updated: 2018-09-14Bibliographically approved
Ljung, A.-L., Andersson, R., Andersson, A. G., Lundström, S. & Eriksson, M. (2017). Modelling the Evaporation Rate in an Impingement Jet Dryer with Multiple Nozzles. International Journal of Chemical Engineering, 2017, Article ID 5784627.
Open this publication in new window or tab >>Modelling the Evaporation Rate in an Impingement Jet Dryer with Multiple Nozzles
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2017 (English)In: International Journal of Chemical Engineering, ISSN 1687-806X, E-ISSN 1687-8078, Vol. 2017, article id 5784627Article in journal (Refereed) Published
Abstract [en]

Impinging jets are often used in industry to dry, cool, or heat items. In this work, a two-dimensional Computational Fluid Dynamics model is created to model an impingement jet dryer with a total of 9 pairs of nozzles that dries sheets of metal. Different methods to model the evaporation rate are studied, as well as the influence of recirculating the outlet air. For the studied conditions, the simulations show that the difference in evaporation rate between single- and two-component treatment of moist air is only around 5%, hence indicating that drying can be predicted with a simplified model where vapor is included as a nonreacting scalar. Furthermore, the humidity of the inlet air, as determined from the degree of recirculating outlet air, has a strong effect on the water evaporation rate. Results show that the metal sheet is dry at the exit if 85% of the air is recirculated, while approximately only 60% of the water has evaporated at a recirculation of 92,5%

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2017
National Category
Fluid Mechanics and Acoustics
Research subject
Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-62886 (URN)10.1155/2017/5784627 (DOI)000397903400001 ()2-s2.0-85015793943 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-04-05 (andbra)

Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2018-11-20Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9789-6293

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