Application of vortex generators to heat transfer enhancement of a pin-fin heat sink

In this paper, the thermal-fluid characteristics of a pin-fin heat sink with delta winglet vortex generators in a cross flow are investigated experimentally and numerically. The effects of the Reynolds number of the flow, the angle of attack of the vortex generators, the shortest distance between the vortex generators, the distance between each vortex generator and the heat sink, the height of the vortex generators, and the configuration of the vortex generators on the performance of the heat sink are explored. The results show that the thermal resistance decreases as the Reynolds number increases, but that the magnitude of the decrease tends to diminish with increasing Reynolds numbers. By considering the thermal resistance and the pressure difference simultaneously, it was determined that an angle of attack of 30° is a better arrangement for the vortex generators. The thermal resistance produced with the shortest distance between the vortex generators equal to the length of the heat sink is lower than that produced with the shortest distance between the vortex generators greater than the length of the heat sink. The heat transfer of the heat sink is higher when the vortex generators are installed against the middle of the heat sink on both sides of it. Although increasing the height of the vortex generators can enhance the heat transfer, the pressure difference also increases. The thermal resistance of the heat sink with the vortex generators arranged in the common-flow-up configuration is lower than that of the heat sink with the vortex generators arranged in the common-flow-down configuration.