太阳能真空集热管内多孔介质强化传热的三维数值模拟  

THREE DIMENSIONAL NUMERICAL SIMULATION OF HEAT TRANSFER ENHANCEMENT USING POROUS MEDIA IN SOLAR VACUUMED COLLECTOR

作　　者：王沛[1] 刘德有[1] 许昌[2] 郭苏[2] 

机构地区：[1]河海大学水利水电学院,南京210098 [2]河海大学能源与电气学院,南京210098

出　　处：《太阳能学报》2012年第12期2105-2110,共6页Acta Energiae Solaris Sinica

基　　金：国家重点基础研究发展(973)计划(2010CB227102)

摘　　要：在实际工况下,对以水为工质的太阳能真空集热管,在采用不同Da数和Rrat(填充比)的多孔介质强化传热方案的管内湍流强制对流换热进行三维数值模拟。结果表明:降低Da数或提高Rrat可使集热管内壁附近的工质速度梯度及温度梯度增大,并使得管内平均Nu数和阻力系数f同时增大,完全填充时f明显增大;比较计算表明,采用Da数为10-5、Rrat为0.8的填充方案较合适。填充了多孔介质的集热管,其管内、外壁面的温度趋向均匀分布,且聚光区与非聚光区的平均温差大幅降低,这将十分有利于降低管表面不均匀热应力引起的管道变形。In operating working condition, based on the theory of heat transfer enhancement in porous, three dimensional simulation was taken to analyze the forced turbulent convection in solar collector by inserting porous medium with different parameters Da number and the ratio of porous Rrat using water as heat transfer medium. The re- suits show that inserting porous medium make the velocity and temperature gradient greater near the tube wall and the heat transfer is enhanced significantly compared to the clear collector, Nu and friction factor f increase at the same time. The optimum fulling method is Da = 10 -5, Rra, =0.8. Temperature distribution of the fluid and the surface of solar collector is more uniform and the temperature difference between the area that receives the reflected solar heat flux and the remaining area is decreased by inserting the porous medium. So the thermal stress generated by the temperature difference of the collector can be decreased to avoid the deformation and injury of the collector

关 键 词：太阳能 真空集热管 多孔介质 强化传热 数值模拟 

分 类 号：TK514[动力工程及工程热物理—热能工程]