Experimental study of flow instability in a natural circulation system with subcooled boiling

摘要

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 the experiments, two kinds of flow instability, flow instability with high frequency and flow instability withlow frequency, were found. It is shown that the flow instability with high frequency belongs to acoustic oscillation and the flow instability with low frequency is density wave instability. In the experiments the influence of the parameters of the working medium on the onset of the flow instabilities in the system was investigated. The stability boundaries were determined through the experiments. By means of dimensional analysis of integral equations, a common correlation describing the threshold condition of onset of the flow instability was obtained.