Abstract: A spectral-based computational algorithm is presented, showing the effects of rotation and curvature on a fluid flow with natural and forced convective heat transfer (CHT) in a rotating curved rectangular channel with an aspect ratio of 3 and curvature ratio ranging from 0.001 to 0.5. The bottom wall of the channel is heated, with cooling from the ceiling; the vertical walls are thermally insulated. The system is rotated about the vertical axis in the positive and negative directions with the Taylor number 2500due to a constant pressure gradient force applied in the stream-wise direction. With the numerical computation presented, five branches of asymmetric steady solution curves comprising single-pair to 11-pair vortices are found. The change in the flow state is then evaluated by means of time-evolution computation, and sketching of the phase space of the solutions enables good prediction of the flow transition. It is found that in the case of co-rotation, a chaotic flow turns into a steady-state flow via a periodic or multi-periodic flow. In the counter-rotation case, however, irregular oscillations change directly to a multi-periodic flow. The study shows appearance of maximum 6-pair vortices at a small curvature, 11-pair vortices at a moderate curvature, and maximum 2-pair vortices at strong curvature. It is also observed that the number of secondary vortices reduces as Tr increases. The vortex structure of secondary flows is also shown in bar diagrams for easy visualization of the effect of curvature on the flow evolution. The study shows that the CHT is significantly enhanced by the secondary flow and a chaotic flow boosts the heat transfer more effectively than other physically realizable solutions. Finally, a comparison between the simulated and experimental results is performed and reasonable matching between the two solutions is observed.

Effects of Rotation and Curvature Ratio on Fluid Flow and Energy Distribution through a Rotating Curved Rectangular Channel / Chanda, R. K.; Hasan, M. S.; Lorenzini, G.; Mondal, R. N.. - In: JOURNAL OF ENGINEERING THERMOPHYSICS. - ISSN 1810-2328. - 30:2(2021), pp. 243-269. [10.1134/S1810232821020089]

Effects of Rotation and Curvature Ratio on Fluid Flow and Energy Distribution through a Rotating Curved Rectangular Channel

Lorenzini G.
;
2021-01-01

Abstract

Abstract: A spectral-based computational algorithm is presented, showing the effects of rotation and curvature on a fluid flow with natural and forced convective heat transfer (CHT) in a rotating curved rectangular channel with an aspect ratio of 3 and curvature ratio ranging from 0.001 to 0.5. The bottom wall of the channel is heated, with cooling from the ceiling; the vertical walls are thermally insulated. The system is rotated about the vertical axis in the positive and negative directions with the Taylor number 2500due to a constant pressure gradient force applied in the stream-wise direction. With the numerical computation presented, five branches of asymmetric steady solution curves comprising single-pair to 11-pair vortices are found. The change in the flow state is then evaluated by means of time-evolution computation, and sketching of the phase space of the solutions enables good prediction of the flow transition. It is found that in the case of co-rotation, a chaotic flow turns into a steady-state flow via a periodic or multi-periodic flow. In the counter-rotation case, however, irregular oscillations change directly to a multi-periodic flow. The study shows appearance of maximum 6-pair vortices at a small curvature, 11-pair vortices at a moderate curvature, and maximum 2-pair vortices at strong curvature. It is also observed that the number of secondary vortices reduces as Tr increases. The vortex structure of secondary flows is also shown in bar diagrams for easy visualization of the effect of curvature on the flow evolution. The study shows that the CHT is significantly enhanced by the secondary flow and a chaotic flow boosts the heat transfer more effectively than other physically realizable solutions. Finally, a comparison between the simulated and experimental results is performed and reasonable matching between the two solutions is observed.
2021
Effects of Rotation and Curvature Ratio on Fluid Flow and Energy Distribution through a Rotating Curved Rectangular Channel / Chanda, R. K.; Hasan, M. S.; Lorenzini, G.; Mondal, R. N.. - In: JOURNAL OF ENGINEERING THERMOPHYSICS. - ISSN 1810-2328. - 30:2(2021), pp. 243-269. [10.1134/S1810232821020089]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2911965
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