Optimal position and perforated radius of punched vortex generators for heat sink

Abstract

An optimal design problem for estimating the design parameters of a delta winglet vortex generator (VG), i.e., its position, attack angle and perforated radius, was investigated in this work to improve the heat dissipation performance of a pin-fin heat sink with CFD-ACE + code and the Levenberg-Marquardt Method (LMM). The role of VGs is to restructure the flow pattern of the inlet air and thus to enhance cooling. Three inlet air velocities with Reynolds numbers Re = 10000, 15000 and 20000 were considered, and the optimization algorithm with LMM was chosen to determine the optimal variables of the VGs to yield the minimum bottom average temperature of the heat sink. Results revealed that the gap between the VG and the heat sink (i.e., position), attack angle and the perforated radius of the VG all became larger as Re increased to improve the cooling performance of the heat sink. In addition, the pressure drop of the heat sink can be significantly reduced due to the perforation of the VGs; as a result, the thermal performance factor of the heat sink is significantly improved. Finally, the designed optimal VGs were installed on a heat sink, and experimental verifications were conducted. The results indicated that the measured temperatures on the bottom plate of the heat sink are similar to the computed temperatures. In addition, the bottom temperatures of the heat sink using the designed optimal VGs are always lower than those using the original design VGs for various Re, which indicates that the heat dissipation performance of the heat sink using optimal VGs is enhanced.