启动加速度对核主泵叶轮内部流动的影响

针对研究不同启动加速度对核主泵启动过渡过程中叶轮内部流动的影响,以3组不同启动加速度瞬态外特性试验性能参数为依据,获得流量与时间和转速与时间的外特性曲线,将获得外特性曲线作为边界条件,代入CFX中进行数值模拟,分析启动过程中外特性曲线及叶轮流道内流线图和压力梯度云图.结果表明:启动加速度与核主泵启动时间有直接关系,但是与流量和转速到达稳定值之间的时间差无关;启动加速度对叶轮内部流动稳定性和压力变化幅度有较大的影响,在启动过渡过程中,较大启动加速度对应叶轮内部流动极不稳定,产生一定强度和面积的旋涡区且压力变化幅度有较大波动,而较小启动加速度对应叶轮内部流动稳定,压力变化幅度均匀.该结果在启动过渡过程中对控制核主泵的不稳定性有重要的价值.

Influence of start-up acceleration on internal flow in impeller of nuclear reactor coolant pump

In order to investigate the influence of different start-up accelerations on the internal flow of the nuclear reactor coolant pump during the start-up period, the experimental data of different transient acceleration external performances were regarded as the basis in this paper, wherein the variations of the flow rate and rotating speed with time were obtained. The obtained characteristic curves were used as boundary conditions into CFX for numerical simulation, besides, the pressure contour and the strea-mline gradient contour were analyzed during the start-up period. The results show that the start-up acceleration is directly related to the start-up time, but is independent of the time difference between the flow rate and the rotating speed reaching the steady value;the start-up acceleration has great influence on the flow stability and pressure amplitude of the impeller. In the start-up transition process, the bigger start-up acceleration corresponding to the inner flow of the impeller is very unstable, producing the vortex area with a certain intensity and area, and pressure fluctuation is large,while the smaller start-up acceleration corresponding to the internal flow of the impeller is stable, the pressure changes in uniform amplitude.The conclusion obtained in this paper is of great importance for the instability control of the nuclear reactor coolant pump in the start-up transition process.