摇摆对棒束通道自然循环流动不稳定性影响研究

Study on Effect of Rolling Motion on Natural Circulation Flow Instability in Rod Bundle Channel

为掌握摇摆条件对于自然循环流动稳定性的影响规律,本研究利用带棒束加热通道的自然循环回路实验系统,开展静态与摇摆条件下的流动不稳定性实验对比研究。实验研究发现,静态条件下棒束通道内存在的流动不稳定性为密度波型脉动(DWO),并形成了预测低压自然循环DWO发生边界的经验关系式;摇摆条件下棒束通道内存在2种典型的两相流动不稳定类型,分别为由棒束通道在流量波动最低点产汽所引起的波谷型脉动和由波谷型脉动和DWO叠加而成的复合型脉动,并分析获得了摇摆影响下自然循环流动不稳定行为的演化规律及其不稳定边界。

In order to obtain the influence of rolling motion condition on the natural circulation flow stability,the natural circulation loop experimental system with a rod bundle heating channel is used to carry out a comparative experimental study of flow instability under static and rolling conditions.The experimental results show that the flow instability existing in the rod bundle channel is density wave oscillation(DWO).An empirical correlation for the DWO boundary prediction at low pressure NC condition is obtained.Two typical two-phase flow instabilities in rod bundle channel under rolling condition are found in experiments:the trough-type oscillation caused by the vapor generation at the lowest point of flow fluctuation and the compound oscillation formed by the superposition of the trough-type oscillation and DWO.The evolution law of flow instability behavior of natural circulation under the influence of rolling as well as its instability boundary are also obtained.