核电站重要厂用水泵叶片磨损对其性能的影响

The Effect of Blade Wear on the Performance of Essential Service Water Pumps in Nuclear Power Stations

为研究叶片磨损对重要厂用水泵水力性能、内流特性等的影响,应用CFD软件基于标准k−ε湍流模型,通过数值计算方法对重要厂用水泵进行定常与非定常计算,分析叶片不同程度磨损下蜗壳流道内水力性能、内流特性、压力脉动的情况。结果表明:叶片磨损会使叶轮流道内湍动能增加,局部产生低压区;随着磨损程度的增加,低压区逐渐向叶轮流道内扩散并最终至全部流道,使重要厂用水泵流场运行不稳定,扬程、效率降低,磨损5/20时扬程和效率与未磨损时相比均降低1.2%;随着磨损程度的增加,压力脉动的波形变得紊乱,轴频幅值仅次于主频,且越来越高,开始占据主导地位;频域图中,峰值随着磨损程度的增加逐渐上升,说明叶片磨损使泵内流动变得不稳定,波动加剧。

In order to study the effect of blade wear on the hydraulic performance,internal flow characteristics of important plant water pumps,CFD software is applied to perform constant and non-constant calculations on essential service water pumps based on the standard k-εturbulence model.The hydraulic performance,internal flow characteristics and pressure fluctuation of volute flow channel under different blade wear were analyzed.The results show that the blade wear will increase the turbulent kinetic energy in the impeller channel and generate a low pressure region locally.With the increase of wear degree,the low pressure zone gradually diffuses into the impeller flow channel and finally reaches all the flow channels,which makes the flow field of important factory pumps unstable,the head and efficiency decrease,and the head and efficiency at 5/20 wear are 1.2%lower than those without wear.With the increase of wear degree,the waveform of pressure pulsation becomes disordered,the amplitude of axial frequency is second only to the main frequency,and it is higher and higher,and it begins to dominate.In the frequency domain diagram,the peak value increases with the increase of wear degree,indicating that the blade wear makes the flow in the pump unstable and the fluctuation intensifies.