Numerical study by large-eddy simulation on effects and mechanism of air-cooling enhancing technologies

ABSTRACTLearning from the lessons of the Fukushima Daiichi Nuclear Power Station incident in which a long-term station blackout occurred, we have been developing an air-cooling system that can operate without electricity for a virtually indefinite time. We developed air-cooling enhancing technologies by using heat transfer fins, turbulence-enhancing ribs and a micro-fabrication surface. To achieve further improvement of the heat transfer performance, it is important to understand the mechanism of the air-cooling enhancing technologies. In this study, we used numerical analysis to investigate the effects and the mechanism of the developed air-cooling enhancing technologies. We confirmed that the Nusselt number was increased 75% by the heat transfer fins. In the heat transfer enhancement by the turbulence- enhancing ribs, the Nusselt number was increased 43% by the turbulence-enhancing ribs. The enhancement ratio of the Nusselt number by the micro-fabrication surface can be explained by the apparent thermal...