Analysis of mixed convection and surface radiation in a horizontal channel containing different finned heat-generating blocks

Abstract

In this work, mixed convection coupled with surface radiation in a ventilated horizontal channel is studied numerically. The channel containing three circular heat sources is ventilated by three openings; an inlet and two outlets. All the walls of the channel are adiabatic, and the flow enters the inlet at a cold temperature. To improve the performance of the cooling system, straight or curved fins are mounted on the surface of the hottest cylinder. The governing equations are discretized and solved using the Galerkin finite element method. The key parameters are the Reynolds number, the surface emissivity, the heat ratio and the geometric parameters of fins (size, number, and form). The numerical results show that the system's thermal performance improves by increasing the Reynolds number and the emissivity. In the absence of surface radiation (ε=0), the results indicate that adding fins leads to a decrease in the maximum temperature of the cylinder by about 6.6 °C for both straight and curved fins. However, the outcomes revealed that for ε=1, straight fins should be chosen instead of curved ones. Finally, for engineering purposes and based on the numerical data, correlations between the maximum temperature and the key parameters have been developed.