水平管冷凝流动不稳定性分析

Analysis of Condensing Flow Instability on Horizontal Tube

通过搭建水平管模型,采用RELAP5程序模拟计算了冷凝管内冷凝流动不稳定性现象,程序计算的稳定性边界与Bhatt理论稳定性公式计算结果符合良好。瞬态分析结果表明,冷凝管内气体压力与两相段长度不匹配是造成冷凝流动不稳定性的主要原因,进而引起冷凝出口流量震荡。冷凝管参数影响分析表明,更小的流动管径与更大的流通截面积有助于冷凝流动稳定,而入口流量的影响则相对复杂。

By building a horizontal condensing tube, the flow instability in condensing tube was simulated using RELAP 5 program in this paper. The results show that the stability boundary of program calculation is in good agreement with that of Bhatt theory stability formula. Transient analysis result shows that vapor pressure and two-phase length in condensing flow do not match, which is the main reason of condensing flow instability and leads to outlet flow rate oscillation. Analysis of condensing tube parame-ters shows that smaller diameter and bigger flow area of condensing tube are of advanta-ges to flow stability, but the influence of inlet flow rate is complicated.