多孔介质太阳能吸热器性能分析

Analysis of the Performance of a Porous Medium Solar Heat Absorber

采用4种多孔骨架中辐射传输模型，包括：忽略多孔骨架内部辐射模型（模型A）、Rosseland模型（模型B）、均匀内热源模型（模型C）与吸热器中辐射传输满足Beer定律的模型（模型D），推导得到了局部非热平衡条件下4种模型所对应的吸热器中多孔骨架温度、空气温度和吸热器热效率的解析解，分析了多孔骨架孔隙率、导热系数和孔隙直径对吸热器性能的影响。结果表明，对模型A和模型B，吸热器中最高温度位于吸热器进口处；对模型C，吸热器中最高温度位于吸热器出口处；而在模型D中，吸热器中吸热器内部或吸热器的出15／处温度最高。吸热器效率取决于多孔骨架导热系数、孔隙率和孔隙直径等参数，当吸热器中内热源均匀分布时，吸热器效率是最高的。

By using four models for irradiation transmitted inside porous skeletons, including the model （Model A） with the irradiation inside the porous skeletons being ignored, Rosseland model （Model B）, uniform inner heat source model （Model C） and the model （Model D） with the irradiation transmission in the absorber in agreement with the Beer law, obtained through derivation were the analytic solutions to the temperatures of the porous skeletons in the heat absorber, air temperature and the thermal efficiency of the absorber corresponding to the four models respectively under the condition of local thermal non-eguilibrium and analyzed the influence of the porosity, heat conductvity coefficient and pore diameter of the porous skeletons on the performance of the absorber. It has been found that for Model A and B, the highest temperature in the absorber is located at the inlet of the absorber, for Model C, the highest temperature is situated at the outlet of the absorber and for Model D, the highest temperature can be at any place inside the absorber or at the outlet of the absorber. The efficiency of the absorber depends on such parameters as the heat conductvity coefficient, porosity and pore diameter etc. of the porous skeletons. When the heat sources inside the absorber are distributed uniformly, the efficiency of the absorber will be the highest.