自然循环过冷沸腾流动不稳定性的实验研究

EXPERIMENTAL STUDY OF FLOW INSTABILITY IN A NATURAL CIRCULATION SYSTEM WITH SUBCOOLED BOILING

本文以氟里昂作工质，对自然循环过冷沸腾流动不稳定性进行了实验研究．实验过程中发现自然循环系统内可能发生高频脉动和低频脉动二种类型的过冷沸腾流动不稳定性．通过实验研究揭示了这二种类型流动不稳定性的发生机理，证实高频脉动属于声波型脉动，低频脉动属于密度波型脉动．通过实验得出了判断系统稳定性的界限，并使用积分方程无因次分析方法得出了预测密度波型流动不稳定性的经验公式．

Experimental study has been performed to investigate flow instability in a natural circulation system with subcooled boiling by using Freon-12 as the working medium. In theexperiments two kinds of flow instability, flow instability with high frequency and flow instability with low frequency, were found. It is shown that the flow instability with highfrequency belongs to acoustic oscillations and the flow instability with low frequency is den-sity wave instability. In the experiments the influence of the parameters of the workingmedium on the onset of the flow instabilities in the system were investigated. The stabilityboundaries were determined through the experiments. By means of dimensional analysis ofintegral equations, a common correlation describing the threshold condition of the onset ofthe density wave instability was obtained.