EFFECTS OF INLET FLOW BOUNDARY CONDITIONS ON THE THERMAL PERFORMANCE OF A PLATE-FIN HEAT SINK WITH AN IMPINGING FLOW

This paper discusses the effect of inlet flow boundary conditions on the performance of a plate-fin heat sink with an impinging flow. The inlet flow boundary conditions of the plate-fin heat sink are decided by duct configurations and heat sink geometries. First, velocity distributions according to the inlet flow boundary conditions of the plate-fin heat sink are obtained using numerical simulations. These results clearly show that the inlet flow boundary condition is divided into two branches: one is uniformly impinging flow and the other is non-uniformly impinging flow. Also, the fluid characteristics of the plate-fin heat sink with an impinging flow according to the inlet flow boundary conditions are experimentally examined by measuring the stagnation pressure distributions on the bottom of the plate-fin heat sink. Based on Do et al., correlations for pressure drop and thermal resistance of the plate-fin heat sink with uniformly impinging flow are proposed. Also, pressure drop and thermal resistance correlations of the plate-fin heat sink with uniformly impinging flow are compared with those of the plate-fin heat sink with non-uniformly impinging flow using correlations suggested by Kim et al. Finally, it is shown that the plate-fin heat sink with uniformly impinging flow has a lower thermal resistance than the plate-fin heat sink the non-uniformly impinging flow when the dimensionless length of the plate-fin heat sink is small and the dimensionless pumping power is large.