熔盐横掠管束传热特性实验研究

Experimental Investigation on Heat Transfer Characteristic of Molten Salt Flow across Tubes

熔盐换热器是塔式太阳能热电站中的重要换热设备之一,以太阳盐(60%NaNO_(3)-40%KNO_(3))为工质,塔式太阳能光热发电参数为实验工况,研究高温熔盐横掠管外的传热特性,分析熔盐进口温度、熔盐流量和水侧流量和水侧压力等因素对熔盐传热特性的影响。实验结果表明:当水侧为单相时,熔盐传热系数随着管壳两侧的质量流速的增大而增大,随着水侧压力的升高而降低,随熔盐入口温度的升高而增大;根据实验数据采用多元线性拟合熔盐与单相水的传热实验关联式,其最大拟合误差为±10%。

Molten salt steam generator is an integral heat transfer device in concentrated solar power(CSP) systems.In this study,according to the solar thermal power generation parameters,a binary salt mixture(60% NaNO_(3) and 40% KNO_(3)) was used as the working substance to study the heat transfer performance of molten salt flow across tubes.The effects of molten salt inlet temperature,molten salt flow flux,and water-side flow flux and water pressure on the heat transfer characteristics of molten salt were analyzed.Experimental results revealed that heat transfer coefficient of molten salt increases with both-sides mass fluxes.It decreases with the increase in water pressure,and increases as molten salt inlet temperature increases.Finally,the fitting correlations of thermal performance of molten salt to single phase water are proposed for the first time,and the fitting values have good consistency with the experimental data,with a maximum deviation of ±10%.