DSG槽式聚光器吸热管壁稳态温度分布的数值研究

Numerical study on temperature distribution of heat-absorbing tube in collector of the DSG system under steady-state conditions

在DSG槽式太阳能聚光器运行过程中,吸热管外表面的热流分布不均易导致吸热管损坏,将严重影响系统的安全。文章以实际辐照为边界热流条件,对集热器吸热管两相区和干蒸汽区截面上的温度分布规律进行了二维数值研究。在稳态条件下,分析了管内不同压强、工质温度和流型对管壁温度场分布的影响。结果表明:压强和温度对干蒸汽区管壁最大周向温差无明显影响,压强较高时两相区管壁温度场分布更均匀;管内为层流时,管壁温度场分布比管内为环流时更不均匀,且整体温度更高。

During operation process of direct steam generation （DSG） in parabolic trough solarthermal power station, the inhomogeneous heat flux distribution on outer surface of absorber tubecan cause damage of the tube and affects on safety of the system. Based on real solar flux, a two-dimensional numerical simulation is carried out, temperature distribution on a section of absorbertube two-phase zone and a section of dry steam zone are researched in the paper. Under steady-state conditions, influences of the pressures, working fluid temperatures and flow patterns on tem-perature fields of the absorber tube are analyzed. The result indicates that the pressures and work-ing fluid temperatures have no significant effect on maximum temperature difference along the cir-cumferential direction of the tube in the dry steam zone, but in the two-phase zone, the higherpressure is, the more homogeneous temperature distribution on the tube wall is; The temperaturedistribution at the condition of stratified flow is more inhomogeneous than that at circulation flow,and temperature of the absorber tube at stratified flow condition is higher than that at circulationflow condition.