强制循环到自然循环过渡过程中流动不稳定性的研究

STUDY ON FLOW INSTABILITY DURING TRANSITION FROM FORCED TO NATURAL CIRCULATION

本文对安装有引射器的回路系统从强制循环到自然循环的过渡特性进行了实验研究和数值模拟，实验结果表明，在过渡过程中、当加热功率超过某一限度，系统内将发生密度波型汽液两相流动不稳定性，危及设备的安全运行。数值模拟采用汽液两相热力学非平衡模型以考虑过冷沸腾对流动不稳定性的影响，使用迭代解法求解差分方程，数值模拟结果与实验结果相当一致。

This paper presents tile study on flow instability during transition from forced to naturalcirculation in the flow system of the thermal utilization equipments of electric power plantsand nuclear power plants. Transient experiments have been carried out on a Freon-12 testloop. The experiments indicate that when the heat input to the input to the heated section exceedsthe threshold value, flow instability may occur in the system during transient, which candamage the equipments. A numerical method to simulate the flow instability in the systemduring transient has been developed. The mathematical model takes account the effect ofthermodynamic non-equilibrium with subcooled boiling on density wave instability in thesyatem. The calculated results are in good agreement with the experimental data.