Experimental and numerical investigations on optimal distribution of heat source array under natural and forced convection in a horizontal channel

The present paper deals with natural and forced convection cooling of a heat source array made of aluminum, mounted on a substrate board in horizontal or vertical orientation, placed in a horizontal channel. The objective of the work is to find the optimal distribution of heat source array so as to minimize the maximum excess temperature and to study the effect of substrate board conduction on heat transfer. Natural convection cooling experiments are performed with heat flux values of 1500, 2000 and 2500 W/m2 and laminar forced convection experiments are performed with the same heat fluxes at air velocities of 0.27 m/s and 0.45 m/s. An optimal configuration for the heat sources have been defined based on a geometric parameter λ, taken from literature. From the experiments and simulations it is found that λ = 1.3 is the optimum configuration. The effect of substrate conduction is studied numerically considering board materials of different thermal conductivities. The numerical simulations are done using COMSOL Multiphysics 4.3b and the results are found to be in good agreement with experiments.