ENHANCEMENT OF WATER COOLING PERFORMANCE IN NARROW FLOW PASSAGES BY USING MICRO HEAT SINKS WITH MINIATURE VORTEX GENERATORS

摘要

This study describes a possibility of an improvement of water cooling devices for high-power electronic devices such as inverters for electric vehicles by using a combination of micro heat sinks and miniature vortex generators. Power devices such as IGBT (Insulated Gate Bipolar Transistor) are widely used for controlling an operation of electronic vehicles and hybrid vehicles. Due to the improvement of the performance of the power devices, the heat dissipation density from these devices becomes higher. The water cooling is the commonest method for dissipating heat from the inverter of the electronic vehicles. Therefore the improvement of the water cooling technology is significantly needed in order to manage the increase of the heat dissipation density. We are now trying to develop a high-performance water cooling device for dissipating the high heat flux from the inverters in the electric vehicles by using a combination of a fine miniature heat sink and a miniature vortex generator. The combination of the miniature heat sink and the vortex generator may increase heat transfer performance of the heat exchanger while inhibiting an increase of pressure drop by generating a swirling turbulent flow in a clearance between the heat sink fins. In this study, the water cooling performance in the narrow flow passage, which simulates the flow passage in the water cooling device, with the miniature heat sink and the miniature vortex generators was investigated by using 3-dimentional CFD analysis. From the analysis, we conclude that the combination of the miniature heat sink and the vortex generator was effective for the heat transfer enhancement in the narrow flow passage of the water cooling device while inhibiting the generation of the pressure drop when we can use the combination with the appropriate manner.