核主泵小流量工况压力脉动特性

Pressure pulsation of a reactor coolant pump under low flow conditions

为研究小流量工况下核主泵内部压力脉动的变化规律,基于雷诺时均N-S方程和标准k-ε两方程及SIMPLEC算法,应用CFX软件对核主泵小流量工况进行定常和非定常数值计算,得到泵内部流场和各工况监测点的压力脉动,并将时域信号进行快速傅里叶变换为频域信号。结果表明:核主泵内压力脉动明显,叶频在由压力脉动诱发的振动中起主导作用,主要表现为叶轮和导叶间的动静干涉。叶轮导叶流道内的回流造成了小流量工况叶轮和导叶流道及其周向的不稳定压力脉动,回流主要存在于叶轮和导叶进出口位置,因此该区域的压力波动剧烈且周期性差。核主泵的振动,不利于核电站的安全稳定运行,通过对小流量工况的压力脉动分析,对预测核主泵在极端工况下的动态特性和推进核主泵国产化具有十分重要的意义。

In order to study pressure pulsation of a reactor coolant pump under low flow conditions, based on Reynolds-averaged Navier-Stokes equations with a standard k-8 turbulence model and SIMPLEC algorithm, using the computational fluid dynamics software CFX to do numerical simulation calculations, the flow field insider the pump and pressure pulsations of monitored points under various working conditions were obtained. Fast Fourier Transformation （Fgl＇） was used to transform time-domain pressure signals into frequency-domain pressure ones. The results showed that pressure pulsation in a reactor coolant pump is obvious; the blade frequency plays a dominant role in the vibration induced by the pressure pulsation, dynamic-static interference between the impeller and guide vane anifests itself; the reflow in the impeller diffuser flow channel leads to the unsteady pressure pulsations of the impeller diffuser flow channel and its circumferential direction under low flow conditions ; the reflow of the reactor coolant pump internal flow channel under low flow conditions exists at the inlet and outlet of the impeller and guide vane, so the pressure pulsation in these regions is violent and weakly regular; pressure pulsation causes pump vibration, it is harmful to the safe and stable operation of a nuclear power plant. Through above analysis, the dynamic characteristics of a reactor coolant pump under the extreme conditions were predicted. The study results were helpful for promoting reactor coolant pumps to be domestic products.