槽式集热器吸热管外混合对流换热数值模拟

NUMERICAL SIMULATION OF MIXED CONVECTION OUTSIDE THE PARABOLIC TROUGH SOLAR RECEIVER

本文总结了太阳能抛物槽式集热器吸热器玻璃管外对流换热的影响因素。在Shiraz 250 kW槽式太阳能热发电系统集热器结构基础上,采用最佳口径比,设计了几种结构参数不同且具有典型意义的集热器;并对所设计不同集热器结构及位置因素影响下的吸热管外混合对流换热进行了数值模拟。模拟结果表明:吸热管外混合对流平均换热热损失随集热器距地距离增大而增大,但增幅越来越小;随集热器两半反射器间间距增大而减小。而不同结构参数下混合对流换热热损失,主要受到风流在不同运行方位下由于集热器阻滞所形成的风流压力场及速度场的影响,且随结构参数呈一定趋势变化。在此基础上进一步可研究吸热器复杂耦合传热过程。

In this paper, the effect factors of the mixed convection outside a parabolic trough solar receiver are summarized. Based on the configuration of the collector of the Shiraz 250 kW parabolic trough solar thermal electric generation system, several different and typical collectors are designed by adopting the optimal aperture ratio. And the effects of these collector configurations and positional parameters on the mixed convection outside the receiver are numerically simulated. The results show that the mixed convection heat loss outside the parabolic trough solar receiver increases with the increase of the distance from the collector to the ground but the increasing trend gradually decreases, decreases with the increase of the gap between the two parts of the collector. The heat loss is influenced by the pressure and velocity field of wind flow formed by these different collector configurations and operation angles, and exhibits a certain variation trend with the constructure parameters. From this work, a further study on the complicated coupled heat transfer of the receiver tube can be carried out.