Numerical Investigation of Heat Transfer in a Channel with Delta Winglet Vortex Generators at Different Reynolds Numbers

Authors: N. K. Singh

Abstract:

In this study the augmentation of heat transfer in a rectangular channel with triangular vortex generators is evaluated. The span wise averaged Nusselt number, mean temperature and total heat flux are compared with and without vortex generators in the channel at a blade angle of 30° for Reynolds numbers 800, 1200, 1600, and 2000. The use of vortex generators increases the span wise averaged Nusselt number compared to the case without vortex generators considerably. At a particular blade angle, increasing the Reynolds number results in an enhancement in the overall performance and span wise averaged Nusselt number was found to be greater at particular location for larger Reynolds number. The total heat flux from the bottom wall with vortex generators was found to be greater than that without vortex generators and the difference increases with increase in Reynolds number.

Keywords: Heat transfer, channel with vortex generators, numerical simulation, effect of Reynolds number on heat transfer.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1090605

References:

[1] Schubauer, G. B. and Spangenberg, W. G., "Forced mixing in boundary layers", J. Fluid Mech., Vol. 8, 1, 1960, pp.10-32.
[2] Fiebig, M., Brockmeier, U., Mitra, N.K., Guntermann, T., "Structure of velocity and temperature fields in laminar channel flows with longitudinal vortex generators," Numerical Heat Transfer, A-15, 1989, pp. 281–302.
[3] Edwards, F.J., Alker, G.J.R., "The improvement of forced convec-tion surface heat transfer using surface protrusions in the form of (a) cubes and (b) vortex generators", Proceedings of the Fifth International Heat Transfer Conference Tokyo, 2, 1974, pp. 2244–2248.
[4] Katoaka, K., Doi, H., Komai, T.," Heat/mass transfer in Taylorvortex flow with constant axial flow rates", International Journal of Heat and Mass Transfer, 20, 1977, pp. 57–63.
[5] Fiebig, M., Kallweit, P., Mitra, N.K., Tiggelbeck, S., "Heat transfer enhancement and drag by longitudinal vortex generators in channel flow", Experimental Thermal and Fluid Science, 4, 1991, pp. 103–114.
[6] Biswas, G., Chattopadhyay, H., "Heat transfer in a channel with built-in wing-type vortex generators", International Journal of Heat and Mass Transfer, 35, 1992, pp. 803–814.
[7] Deb, P., Biswas, G., Mitra, N.K., "Heat transfer and flow structure inlaminar and turbulent flows in a rectangular channel in longitudinal vortices", International Journal of Heat and Mass Transfer, 38, 1995, pp. 2427– 2444.
[8] Biswas, G., Torii, K., Fujii, D., Nishino, K., "Numerical and experimental determination of flow structure and heat transfer effects of longitudinal vortices in a channel flow", International Journal of Heat and Mass Transfer, 39, 1996, pp. 3441–3451.
[9] Biswas, G., Deb, P., Biswas, S., "Generation of longitudinal streamwise vortices – A device for improving heat exchanger design", Journal of Heat Transfer (ASME), 116, 1994, pp. 588–597.
[10] Sohankar, A., Davidson, L., "Numerical study of heat and fluid flowin a plate-fin heat exchanger with vortex generators", Turbulence Heat and Mass Transfer, 4, 2003, pp. 1155–1162.
[11] Shan, H., Jiang, L., Liu C., Love, M. and Maines, B., "Numerical study of passive and active flow separation control over a NACA0012 airfoil", Computers and Fluids, 2008, 37, pp.975-992.
[12] Henze, M., Wolfersdorf, J., Weigand, B., Deitz, C. F. and Neumann, S. O.," Flow and heat transfer characteristics behind vortex generators - A benchmark dataset", Int. J. Heat Fluid Flow, 2011, 32, pp. 318-328.
[13] Hiravennavar, S. R., Tulapurkara, E.G., Biswas, G., "A note on the flow and heat transfer enhancement in a channel with built-in winglet pair", International Journal of Heat and Fluid Flow, 2007, 28, 2, pp. 299-305.