窄隙自然循环过冷沸腾流道中的温度分布特性

Experimental study of temperature distribution in vertical narrow annuli with subcooled boiling in a naturally circulating system

针对一体化反应堆的窄通道和自然循环特点,在常压下,以水为工质,对竖直窄环隙流道进行了自然循环过冷沸腾换热实验研究,通过对流道内温度的测量,考察了入口过冷度、流道间隙和加热负荷对流道内温度分布的影响.结果表明,在中低负荷区,流体的截面温度基本不受加热负荷的影响,入口过冷度使轴向壁温分布呈现非单调性变化,在一定条件下会引起沸腾区壁温的逆向升高,减小流道间隙或增大加热负荷有助于弱化入口过冷度的影响,减小流道间隙还有利于降低壁面温度,但流道间隙也不宜过小.

Subcooled boiling in vertical narrow annuli was investigated experimentally, with natural circulation, under atmospheric pressure, and using water as working medium. Attention was focused on the effect of inlet subcooling, gap width and heat flux on temperature distribution in the axial direction. Measured data showed that the cross-section fluid temperatures were hardly affected by heating power when input power value is not very high. The wall temperature distribution from inlet to exit is not monotone because of inlet subcooling. The wall temperature in the boiling region even increases with the increase of inlet subcooling when inlet subcooling is low. Reducing the gap width or increasing heating power is beneficial for decreasing the influence of inlet subcooling. Decreasing gap width also leads to lower wall temperature.