多点聚焦的太阳能柱式吸热器能流分布研究

Analysis of the Solar Thermal Cylinder Receiver Heat Flux Distribution Under Multi-aiming Point Strategy

塔式太阳能热发电站定日镜场通常采用多点聚焦策略来降低吸热器表面辐射能流的不均匀性,防止发生过热故障。文中以塔式电站柱式吸热器单根吸热管为研究对象,采用具有多个极大值的高斯函数来描述多点聚焦时吸热管表面具有多个能流集中点的辐射能流分布,数值模拟分析吸热管的热参数特性。结果显示:聚焦点个数一定时,存在最优的聚焦点位置,使得吸热管表面辐射能流不均匀性最低。同时随着聚焦点个数增加,吸热管表面辐射能流更加均匀,最大壁温减小,而轴向最大绝对温度梯度增大。因此对于多点聚焦,应综合考虑吸热管的热参数,选择最优化的聚焦点个数和聚焦点位置。

Generally, the heliostat field in the solar thermal power tower plant used the multi-aiming point strategy to reduce the non-uniformity of radiation heat flux on the receiver to prevent the overheating. In this paper, a single tube used in solar thermal power tower cylinder receiver was studied theoretically. The heat flux on the tube using the multi-aiming point strategy with multiple concentrated points was achieved by the Gaussian function with multiple maximum values. The thermal parameters characteristic were analyzed by numerical simulation. The results show that each aiming point has the optimal position making the lowest non-uniformity of the radiation heat flux on the tube when the number of the aiming point is constant. What＇s more, the radiation heat flux on the tube is more and more uniform and the maximum wall temperature decreases with the number on the aiming point increasing, while the maximum absolute temperature gradient increases. As a consequence, the thermal parameters must be considered comprehensively according to the multi-aiming point strategy to choose the optimal number of the aiming point and their optimal positions.