Conjugate Heat Transfer of Laminar Air Flow in Rectangular Mini Channel
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Abstract
Conjugate heat transfer has significant implications on heat transfer characteristics, particularly in thick wall applications and small diameter pipes. In this study, a three-dimensional numerical investigation was carried out using commercial CFD software “ANSYS FLUENT” to study the influence of conjugate heat transfer of laminar flow in mini channels at constant heat flux wall conditions. Two parameters were studied and analyzed: the wall thickness and thermal conductivity and their effect on heat transfer characteristics such as temperature profile and Nusselt number. Thermal conductivity of (0.25, 10, 202, and 387) W/m2C and wall thickness of (1, 5, and 50) mm were used for a channel of (1*2) mm cross-sectional dimensions. Taking the Reynolds number 800 for all cases. The results demonstrate that the conjugate conduction impact is observed at high conductivities and for large wall thicknesses in the studied materials. This impact flattened the wall temperature distribution along the channel wall instead of being an augmented linear profile. Also, it flattens the local Nusselt number due to the axial heat conduction along the walls. It reduces the effect of the entrance region of high Nusselt number while making the fluid temperature profile curved and redistributing the wall heat flux and accumulating it toward the leading edge. A decrease was observed in the average Nusselt number of 8% when increasing wall thickness from 1 mm to 50 mm for the same thermal conductivity of 10 W/m2C, while an increase in Nusselt number of 19% with thermal conductivity changes from 0.25 W/m2C to 10 W/m2C.
Article received: 11/1/2022
Article accepted: 24/3/2022
Article published: 1/7/ 2022
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References
• Abdollahzadeh, M., et al., 2017. Assessment of RANS turbulence models for numerical study of laminar-turbulent transition in convection heat transfer, International Journal of Heat and Mass Transfer, 115, pp. 1288–1308
• .
• Ajeena, A.M., and Al-Madhhachi, H.S., 2020. Advanced thermal analysis of three-dimensional conjugate heat transfer with radial radiation in horizontal pipe for sustainability, Journal of Mechanical Engineering Research and Developments, 43(4), pp. 134–149.
• Al-Zaharnah, I.T., Yilbas, B.S., and Hashmi, M.S.J., 2000. Conjugate heat transfer in fully developed laminar pipe flow and thermally induced stresses, Computer Methods in Applied Mechanics and Engineering, 190(8), pp. 1091–1104.
• Arici, M.E., and Aydin, O., 2009. Conjugate heat transfer in thermally developing laminar flow with viscous dissipation effects, Heat and Mass Transfer/Waerme- und Stoffuebertragung, 45(9), pp. 1199–1203.
• Bilir, Ş., 2002. Transient conjugated heat transfer in pipes involving two-dimensional wall and axial fluid conduction, International Journal of Heat and Mass Transfer, 45(8), pp. 1781–1788.
• Canli, E., Ates, A., and Bilir, S., 2018. Conjugate heat transfer for turbulent flow in a thick walled plain pipe, EPJ Web of Conferences, 180, pp. 1–8.
• Carlson, J.-R., 2011. Inflow/Outflow Boundary Conditions with Application to FUN3D, National Aeronautics and Space Administration, (October), pp. 1–38.
• Hajmohammadi, M.R., Rahmani, M., Campo, A., and Joneydi Shariatzadeh, O., 2014. Optimal design of unequal heat flux elements for optimized heat transfer inside a rectangular duct, Energy, 68, pp. 609–616.
• He, J., Juan He, Qinghua D., Weilun Z., Wei H., Tieyu G., Zhenping F., 2020. Conjugate Heat Transfer Characteristics of Double Wall Cooling on a Film Plate With Gradient Thickness, ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition .
• Holman, J.P., 2010. Heat Transfer, tenth edition.
• Joneydi Shariatzadeh, O., 2016. Analytical solution of conjugate turbulent forced convection boundary layer flow over plates, Thermal Science, 20(5), pp. 1499–1507.
• Karvinen, R., 1978. Some new results for conjugated heat transfer in a flat plate, International Journal of Heat and Mass Transfer, 21(9), pp. 1261–1264.
• Khalesi, J., and Sarunac, N., 2019. Numerical analysis of flow and conjugate heat transfer for supercritical CO2 and liquid sodium in square microchannels, International Journal of Heat and Mass Transfer, 132, pp. 1187–1199.
• Kokugan, T., KINOSHITA, T., TANIGUCHI, N., and SHIMIZU, M., 1975. Natural convection flow rate in a heated vertical tube, Journal of Chemical Engineering of Japan, 8(6), pp. 445–450.
• Kuznetsov, G. V., and Sheremet, M.A., 2010. Turbulent regime of thermogravitational convection in a closed cavity, Journal of Engineering Physics and Thermophysics, 83(2), pp. 346–357.
• Malvandi, A., Hedayati, F., and Ganji, D.D., 2015. Onset of the mutual thermal effects of solid body and nanofluid flow over a flat plate theoretical study, Journal of Applied Fluid Mechanics, 8(4), pp. 835–843.
• Méndez, F., and Treviño, C., 2000. The conjugate conduction-natural convection heat transfer along a thin vertical plate with non-uniform internal heat generation, International Journal of Heat and Mass Transfer, 43(15), pp. 2739–2748.
• Merkin, J.H., and Pop, I., 1996. Conjugate free convection on a vertical surface, International Journal of Heat and Mass Transfer, 39(7), pp. 1527–1534.
• Mohammed, H.A., and Salman, Y.K., 2007. Laminar air flow free convective heat transfer inside a vertical circular pipe with different inlet configurations, Thermal Science, 11(1), pp. 43–63.
• Mohammed, H.A., and Salman, Y.K., 2008. Numerical study of combined convection heat transfer for thermally developing upward flow in a vertical cylinder, Thermal Science, 12(2), pp. 89–102.
• Satish, N., and Venkatasubbaiah, K., 2016. Conjugate heat transfer analysis of turbulent forced convection of moving plate in a channel flow, Applied Thermal Engineering, 100, pp. 987–998.
• Tiselj, I., and Cizelj, L., 2012. DNS of turbulent channel flow with conjugate heat transfer at Prandtl number 0.01, Nuclear Engineering and Design, 253, pp. 153–160.
• Varol, Y., Oztop, H.F., and Koca, A., 2008. Entropy generation due to conjugate natural convection in enclosures bounded by vertical solid walls with different thicknesses, International Communications in Heat and Mass Transfer, 35(5), pp. 648–656.
• Yapici, H., and Albayrak, B., 2004. Numerical solutions of conjugate heat transfer and thermal stresses in a circular pipe externally heated with non-uniform heat flux, Energy Conversion and Management, 45(6), pp. 927–937.