Study Of The Heat Transfer Characteristics In A Channel With One Surface Having Mini-grooves And A Plain Surface Located At A Mini-distance

IGBT (Insulated gate bipolar transistors) have been widely used in power transmissionsystems, supplies, converters, etc., and are the key component to realize the functions of thesefacilities. However, the swith is turned on and off quite frequently when it is operated, thus asignificant amount of electric energy is converted into heat. It is necessary to maintain thetemperature of the transistor junction in the power component below the maximum allowabletemperature for its normal operation. As known, when the heat flux is more than100W/cm2,traditional cooling method has failed to meet the requirements. Thus, a mini-grooved surfacechannel is designed in the paper, which is composed of one surface having mini-grooves inthe flow direction and another plain surface located at a mini-distance. The surfaces arearranged as a sandwiched-type cooler, in which the core plate with plain surfaces is locatedbetween two cold plates with one surface having mini-grooves. Two IGBT units are mountedon the outside wall of the cold plates to save space. The heat transfer characteristics in themini-grooved surface channel are investigated both experimentally and numerically.The content includes the designing and implementing the test specimens and theexperimental systems, investigating the heat transfer characteristics of the mini-groovedsurface channel and the plain-surface channel, evaluating the heat transfer enhancementperformance of the mini-grooved surface channel by a new coefficient of performance (COP),and analyzing numerically the flow and the heat transfer characteristics of the mini-groovedsurface channel based on the SIMPLE algorithm.The results show that the mini-grooved surface channel can enhance the heat transfersignificantly, the ratio of the heat transfer rate between the mini-grooved surface and the plainsurface is all larger than1.0under identical mass flow rate, the identical pressure drop, andthe identical pumping power criteria. The numerical results are agreed well with theexperimental results. This crossly verifies the accuracy of the experiments and the feasibilityof the numerical simulation. The mini-grooved surface channel can enhance the heat transfereffectively and have an advantage over the existed general micro-grooved channel coolerwhen a large area needs to be cooled.