Thermal performance of smart heat sinks for cooling high power LED modules

This paper reports the thermal performance of smart heat sinks (SHSs) consisting of hybrid pin fins (HPFs) containing internal channels and integrated with plate fins. The SHSs are mainly aimed at cooling high power LED modules under natural convection condition or forced convection condition with a moderate air velocity. The computational fluid dynamics (CFD) models of SHSs are generated utilizing a commercial CFD software package. The CFD analysis evaluates the cooling performance as well as the basic thermal behavior of the SHSs under various parametric conditions such as heat dissipations ranging from 5 to 20W, air velocities ranging from 0 to 3m/s, and fin spaces of 12, 15, and 20mm. The cooling performance of the SHSs is compared with those of conventional pin fin heat sinks (PHSs). Parametric study has found that thermal resistances of the SHSs are typically smaller than those of the PHSs; for example, they are 15% smaller than the PHS under natural convection. Parametric results show that 15mm is the best fin space for SHSs. This study also explores the effect of the declination angles between the symmetry axis of the fin and the axis of the gravity on the performance of HPFs under natural convection. The results show the thermal resistance value of the HPF decreases with the increase of the declination angle.