Constructal enhancement of cooling performance of local heating elements with different heat generation rates under free and mixed convection regimes

This study aims to obtain the optimum heat generation rate of local heating elements with different heat generation rates in a vertical duct. Covering free and mixed convection regimes, experimental and numerical studies are conducted. Various values of the modified Grashof and Reynolds numbers are taken into account. The influence of the heat generation rates of local heating elements on temperature of the hot spot, local temperatures, system's global conductance and Nusselt number are presented. It is shown that the heating elements with coheat generation rates cause a rise in the temperature of the hot spot and reduce the global conductance, and the gradual decrease in the heat generation rates of heating elements improves the system's cooling performance.