Research On Heat Transfer Characterstic Of Porous Media Receiver

Due to its special characteristics such as Thermostability, antioxidation, highspecific surface and high thermal conductivity, porous media is ideal material for heattransfer enhancement in solar cavity receivers, which can enhance heat transfer in solarcavity receivers. Performance of porous media is very important for the receivers, andTemperature and flow field analysis of porous media receiver can provide advices forimproving the performance and efficiency of receivers.The relevant model is established based on local thermal non-equilibrium model(LTNE) combining with the theories of flow and heat transfer in porous media. Flowvelocity, porosity, PPI and the nonuniform heat flux distribution is considered toinfluence the temperature of solid matrix and flowing fluid, and then the performanceanalysis of receiver is conducted.Because of its complex structure, it is very difficult to get the accurate heatradiative parameters of porous media. Therefore, the solid matrix structure is simplifiedas ruled geometries distributed in the fluid zone which is transparent for radiation. Onthe one hand, the volume ruled geometries can be identified to be uniform to the realporous media; on the other hand, the size of the geometries can be adjusted to satisfy thepore density of real ones. Base on the simplified structure, the radiative characteristicscan be computed easily by employing Monte-Carlo Method (MCM). Besides,experiments are conducted to measure the Bidirectional Reflectance DistributionFunction (BRDF) of the SiC foam.