Hybrid conduction, convection and radiation heat transfer simulation in a channel with rectangular cylinder

Abstract

The innovation of this study is to investigate the combination effect of thermal radiation and convection in the hybrid heat transfer between solid and fluid in a channel. The lattice Boltzmann method based on the D2Q9 scheme has been utilized for modeling fluid and temperature fields. Streamlines, isotherms, vortices and Nusselt numbers along the wall surfaces have been investigated for different Reynolds numbers (Re = 10, Re = 60, Re = 133.3), Peclet numbers (Pe = 7.1, Pe = 42.6, Pe = 94.7), the emission coefficients (e = 0.3, e = 0.7, e = 1), radiation coefficients (RP = 0.010, RP = 0.015, RP = 0.020) and diffusion coefficients (αs = αf, αs = αf/2, αs = 2αf). The mean Nusselt number (Num) fluctuations have been analyzed for different cases to predict optimal levels of effective factors of this simulation in order to maximize and minimize the heat transfer rate. The results show that by increasing the Reynolds number to Re = 133.3, the maximum average Nusselt number can be changed by more than 9.249 time. Also by increasing the thermal diffusion coefficient to αs = 2αf, the minimum average Nusselt number can be changed by less than − 0.687 time.