Thermo/fluid performance of a shielded heat sink

Abstract

This research aims at studying the effect of using a heat shield on the performance of a parallel plate -finned- heat sink. Both numerical and experimental approaches were performed. In the numerical part, the flow field and various design parameters of the heat sink were simulated. The simulation is considered three dimensional, viscous, steady, and turbulent. The turbulence model used was RNG k–ε model with enhanced wall treatment approach for the near-wall region. In the experimental part, models for the parallel plate heat sink were manufactured and tested and the results were used to validate the numerical work.A parametric study was conducted to study the effect of varying the design parameters on the performance of the heat sink. These parameters included Reynolds number, fin height, number of fins, and the shield inclination angle. It was found that attaching a shield to the heat sink appears to enhance the thermal performance as indicated by the considerable decrease in the thermal resistance, especially at low Reynolds number. Also, changing of the shield inclination angle causes complicated variation in the flow field around the heat sink and its thermal performance. It was found that the inclination angle that yields minimum thermal resistance varies with heat sink height. For shortest fin height used (H = 15 mm), this resistance is minimum with range θ = 90–120°, while for higher heat sink heights this range is 120–135°. Finally, correlations were developed relating the mean Nusselt number to the dimensionless parameters.