Cooling performance of plate fins for multichip modules

Numerical and experimental studies were carried out to evaluate the air cooling characteristics of plate fins for MCMs (multichip modules) with and without some spanwise space around the plate fins. The flow field in-between the plate fins can be assumed to be similar to that of a parallel plate duct, and hence two dimensional laminar flow analyses using the finite volume method were performed. Calculations were carried out for Res (S/L)=1 to 200 and S/t (plate spacing to plate thickness ratio)=3, 4 and 7. Some empirical equations for the Nusselt number and friction factor based on the numerical results are proposed. Considering the fin efficiency calculated from the conventional conduction fin model, the thermal resistance of the plate fins with no space around the fins could be estimated easily on the basis of the above-mentioned equations. Comparisons with experimental results show that this method is valid for H/S (fin height to plate spacing ratio)⩾7. In the case of H/S=4, the thermal resistance is overestimated by this method. Furthermore, nodal network analyses were carried out to estimate the thermal resistance of the plate fin including some spanwise space by specifying the cooling characteristics of the plate fin with no space around the fin. The good agreement between the predicted results and corresponding experimental data shows that this relatively simple nodal network method is quite useful to estimate the thermal resistance of plate fills including some spanwise space