无阻塞潜水磨碎泵的空化及压力脉动特性研究

Cavitation and pressure pulsation characteristics of a non-jamed submerged grinder pump

由于磨碎泵在实际运行中刀盘的流道容易发生堵塞,本文主要模拟磨碎泵静刀盘的刀盘流道堵塞情况对磨碎泵性能的影响,该模拟基于ANSYS-CFX14.0软件分别对无阻塞潜水磨碎泵模型进行定常和非定常计算,并对无阻塞潜水磨碎泵的外特性进行了试验验证。分别堵塞磨碎泵静刀盘流道的1/4、1/3、1/2,通过对不同的流道堵塞工况分析发现:随着流道堵塞程度的增加,潜水磨碎泵的扬程整体下降,潜水磨碎泵的功率整体下降,效率降低,且最高效率点向小流量区域移动,可发现当堵塞静刀盘流道的1/4、1/3时,对磨碎泵的扬程、效率和功率的影响不大,堵塞1/2时,磨碎泵的扬程和效率下降明显,即堵塞不严重的工况下,磨碎泵的水力性能所受影响很小;随着流道堵塞程度的增加,刀头附近的空化程度在加剧,当堵塞比达到一定程度时,叶轮进口背面也开始发生空化;静刀盘流道内压力脉动脉动能量最大,且随着远离静刀盘流道位置的脉动能量降低,动静刀盘的动静干涉作用是影响动刀盘和靠近静刀盘流道的监测点压力脉动的最主要因素,且随着流量的增加,各个监测点主频幅值均有所降低。

In the actual operation,jam of a submerged grinder pump＇s cutter channel is easy to occur. Here,the effects of the grinding pump＇s static cutter channel congestion on the pump performance were simulated. The simulation based on the software ANSYS-CFX14. 0 was condicted to do steady and unsteady calculations for the model of a non-jamed submerged grinder pump and the outside characteristics of the pump were verified with tests. 1 /4,1 /3 and 1 /2 channels of the static cutter of the pump were padded,respectively. The analysis results for different channel blockage conditions showed that with increase in level of runner blockage,the pump lift head overall drops,the power declines,the efficiency reduceds,and the maximum efficiency point moves to the small flow field; when 1 /4 and 1 /3 channels of the static cutter grinding runner are padded,there is little effect on the pump lift head,efficiency and power but when 1 /2 channel is padded,the pump lift head and efficiency decrease significantly; with increase in level of runner blockage,the cavitation close to cutters is intensified and becomes more serious,the cavitation at the back of impeller inlet also becomes more serious; with increase in flow,the monitored point＇s pressure pulsation on the knife disk reduces,the monitored point＇s pressure pulsation on static cutter increases,the pulsating energy of pressure pulsation in the static blade channel is the largest,and the pulsating energy far from the static cutter runner reduces.