Flow and Heat Transfer Characteristics in Latticework Cooling Channels With Dimple Vortex Generators

Abstract

A comparative numerical study has been conducted on the flow and heat transfer characteristics in the latticework cooling structure with three different subchannel configurations: rectangular subchannels, U shaped subchannels and U shaped subchannels with dimple vortex generators. Experiments have been conducted using the latticework structure with U shaped subchannels with dimples. The comparisons between the experimental and numerical data have shown that the numerical computation model can reasonably well predict the heat transfer and pressure loss in the latticework cooling channels. The computation results showed that the latticework cooling structure has significantly enhanced heat transfer performance, and remarkably increased heat transfer area. Over the Reynolds number range of 7,696–36,985, depending on the geometry of the subchannels the average Nusselt number of the latticework channel is about 1.9–2.3 times that of a smooth channel, but the friction factor is about 6.4–11.1 times that of a smooth channel. The U shaped subchannels with dimples provide the greatest heat transfer enhancement and the most uniform heat transfer both axially and laterally, whose average Nusselt number is about 16.0% higher than the other two subchannels. Compared to the U subchannel, the dimples in the U subchannels work as vortex generators and provide additional heat transfer enhancement, whereas distinctively increase the pressure loss. Compared to the latticework cooling with U subchannels, the latticework cooling with rectangular subchannels shows similar average heat transfer the latticework cooling with rectangular subchannels shows similar average heat transfer and pressure loss performance.