Numerical studies on symmetrically and asymmetrically heated vertical channels with isothermal walls
DOI:
https://doi.org/10.24425/ather.2025.156844Abstract
Numerical studies on combined free and forced convection together with radiation in a channel comprising two plates that are vertical and parallel are made. The channel here addresses two cases, viz. symmetric, and asymmetric isothermal walls. The cooling agent could be any gaseous medium that is assumed transparent to thermal radiation. The present work considers air for the job. The equations of conservation of mass, momentum and energy are solved through the finite volume method and an explicit code is prepared for this. The prime independent parameters considered are: aspect ratio, wall emissivity, Richardson number, Grashof number and Reynolds number. The effects exhibited by these parameters on the average convection Nusselt number, and the contributory roles enacted by convection and radiation in discarding the heat in the channel have been elucidated. The correlations for the mean convection Nusselt number and mean radiation Nusselt number are deduced through regression analysis using a large set of data gathered from the computer code that is prepared as part of the present work. The gross errors that occur in the cooling load calculations upon ignoring radiation in problems of this kind are clearly demonstrated.References
[1] Carpenter, J. R., Briggs, D. G., & Sernas, V. (1976). Combined radiation and developing laminar free convection between vertical flat plates with asymmetric heating. ASME Journal of Heat Transfer, 98(1), 95–100. doi:10.1115/1.3450476
[2] Sparrow, E. M., Shah, S., & Prakash, C. (1980). Natural convection in a vertical channel: 1. Interacting convection and radiation; 2. The vertical plate with and without shrouding. Numerical Heat Transfer, 3(3), 297–314. doi:10.1080/01495728008961760
[3] Anand, N. K., Kim, S. H., & Aung, W. (1990). Effect of wall conduction on free convection between asymmetrically heated vertical plates: Uniform wall temperature. International Journal of Heat and Mass Transfer, 33(5), 1025–1028. doi:10.1016/0017-9310(90)90083-7
[4] Kim, S. H., Anand, N. K., & Aung, W. (1990). Effect of wall conduction on free convection between asymmetrically heated vertical plates: Uniform wall heat flux. International Journal of Heat and Mass Transfer, 33(5), 1013–1023. doi:10.1016/0017-9310(90)90082-6
[5] Kim, S. H., & Anand, N. K. (1994). Laminar developing flow and heat transfer between a series of parallel plates with surface-mounted discrete heat sources. International Journal of Heat and Mass Transfer, 37(15), 2231–2244. doi:10.1016/0017-9310(94)90366-2
[6] Hacohen, J., Chiu, T. W., & Wragg, A. A. (1995). Forced and free convective heat transfer coefficients for a model printed circuit board channel geometry. Experimental Thermal and Fluid Science, 10(3), 327–334. doi:10.1016/0894-1777(94)00073-H
[7] Watson, J. C., Anand, N. K., & Fletcher, L. S. (1996). Mixed convective heat transfer between a series of vertical parallel plates with planar heat sources. ASME Journal of Heat Transfer, 118(4), 984–990. doi:10.1115/1.2822601
[8] Gururaja Rao, C. (2004). Buoyancy-aided mixed convection with conduction and surface radiation from a vertical electronic board with a traversable discrete heat source. Numerical Heat Transfer, Part A: Applications, 45(9), 935–956. doi:10.1080/10407780490439202
[9] Mamun, A. A., Chowdhury, Z. R., Azim, M. A., & Maleque, M. A. (2008). Conjugate heat transfer for a vertical flat plate with heat generation effect. Nonlinear Analysis: Modelling and Control, 13(2), 213–223. doi:10.15388/NA.2008.13.2.14581
[10] Malvandi, A., & Ganji, D. D. (2014). Mixed convective heat transfer of water/alumina nanofluid inside a vertical microchannel. Powder Technology, 263, 37–44. doi:10.1016/j.powtec.2014.04.084
[11] Londhe, S. D., & Gururaja Rao, C. (2014). Interaction of surface radiation with conjugate mixed convection from a vertical channel with multiple discrete heat sources. Heat and Mass Transfer, 50, 1275–1290. doi:10.1007/s00231-014-1333-1
[12] Shah, A. P., & Gururaja Rao, C. (2020). Buoyancy-aided conjugate mixed convection with surface radiation from a vertical channel with multiple non-identical discrete heat sources. International Journal for Computational Methods in Engineering Science and Mechanics, 21(1), 12–25. doi:10.1080/15502287.2020.1718799
[13] de Araujo, M. E. V., Barbosa, E. G., Martins, M. A., & Corrêa, P. C. (2022). Conjugated analysis of heat transfer by natural convection and radiation in a fin array using a semitransparent fluid medium. Heat and Mass Transfer, 58, 1119–1132. doi:10.1007/s00231-021-03163-1
