Development of prediction technique for cooling performance of finned heat sink in uniform flow

Numerical simulation was carried out on the flow and the temperature fields around a plate fin array subjected to a uniform flow, varying the ratio of fin length L to the half-pitch of fins s. As Re₀s/L decreased, the flow approaching the fin array had a tendency to bypass it and thus the average flow velocity through fins U _f became lower, where Re₀ is the Reynolds number defined by uniform flow velocity and s. It was also found that frictional resistance and heat transfer of the fins showed excellent agreement with those for the developing flow between parallel plates with uniform inlet flow velocity equal to U_f. A prediction technique for the cooling performance of the array was developed in which U_f was estimated under the condition of constant pressure distribution at its downstream edge. The present technique can predict the heat transfer of the fin array with an error level below 30% under practical conditions of electronics design, although it underestimates U_f in the region of small Re₀s/L