混流泵径向间隙对内部非定常流场影响的分析

Effect of Volute Tongue-impeller Gaps on the Unsteady Flow in Mixed-flow Pump

采用调整混流泵径向间隙的方法,设计了蜗壳基圆直径为280、290、300mm的计算模型,并对其进行了定常和非定常计算.通过对3种模型进行非定常数值计算,得到了不同基圆直径混流泵的压力脉动特性并对其进行比较分析.结果表明:叶轮旋转时叶片和隔舌的动静干涉作用导致蜗壳近壁面各监测点的压力脉动具有明显的周期性;在相同流量下,径向间隙越小,监测点频域振幅越大;隔舌处监测点压力脉动幅度大于其他监测点幅度.对基圆直径为290mm的泵进行数值模拟与外特性试验研究,泵模拟效率为82.3%,试验效率为80%,模拟效率比试验效率高2.3%.对比两者结果可知:数值模拟的结果是可信的.

The three-dimensional steady and unsteady numerical method was applied to simulate the flow in the mixed-pump with different volute casings.The base circle diameters of three volute casings were 280 mm,290mm and 300mm,the characters of the pressure fluctuation were obtained with different base circle diameters.The results show that the pressure pulsation presen-ted an obvious periodicity.At the same flow rate,the smaller the radial clearance,the larger frequency domain of pressure fluctu-ation at each monitoring point.The fluctuation amplitude near the volute tongue is larger than other points.For the mixed-pump with 290mm volute base circle diameters its performance experiments and numeric simulations were done.The calculated results are in good agreement with measurement results.Numerical simulation is believable.