Influence Of Vortex Generator Layout On The Thermal Performance Of Solar Air Collector

Solar air collector are the most widely used and simplest form of solar light-heat application.Collector is the core component of solar thermal utilization system.The efficient heat transfer between collector and air is one of the key technologies.Due to the physical property limitation of air,as the heat-transfer medium of solar air collector,has a low heat transfer rate with the absorber plate.The lower heat exchange rate causes the collector bottom plate to heat up,which leads to an increase in radiant heat loss.Therefore,how to effectively enhance heat transfer and reduce radiant heat loss has a great significance for improving the application of solar air collectors.For enhanced heat transfer,there are two ways to change the shape of the collector plate or to artificially roughen the collector plate.In this paper,the artificial roughening method is adopted,that is,the research work is carried out by arranging four kinds of vortex generators,such as triangular cone,cylinder,cube and regular triangular prism,on the bottom plate of the collector.Firstly,the heat transfer performance of the collector is studied by orthogonal experiment method and numerical simulation,The vortex generator shape,height,spacing,arrangement and the inlet flow those could affect the thermal efficiency is studied in detail.By analyzing the influence of these five factors on the heat collection efficiency,the best working conditions are obtained.Then,based on the results of the orthogonal test extremum difference analysis,to explore the effects of various factors on heat transfer performance.By comparison with Nu₀ and f₀ of the smooth collector plate,The mechanism of the built-in eddy current collector collector is revealed,which provides a theoretical basis for its optimization.Finally,combining the conclusions of each chapter and the results of previous studies,three dimensionless numbers affecting the heat transfer performance of solar air collectors are proposed.The factor analysis method is used to summarize the Nusselt number and frictional resistance coefficient criterion for the solar air collector floor of the built-in vortex generator.