来流含不凝性气体的诱导轮空化流动实验研究

Experimental study on cavitating flow characteristics of inducer with inflow entrained non-condensable gas

为研究来流含有的不凝性气体对诱导轮空化流动的影响,基于诱导轮泵注气空化流动可视化实验台进行了一系列实验,得到了不同入口不凝性气体含气率下诱导轮泵的外特性、空化区发展形态以及相应的空化不稳定特性。结果表明:随着入口不凝性气体含气率的增加,诱导轮的扬程断裂空化数上升;随着来流不凝性气体含气率的增加,不凝性气体被泄漏涡和回流涡卷吸,导致泄漏涡空化以及回流涡空化长度显著延长;此外,不凝性气体在小空化数(Φ=0.083、σ=0.090和Φ=0.071、σ=0.068)下增加了空穴的可压缩性,从而对空化喘振具有一定的抑制作用。

To study the effect of inflow entrained non-condensable gas on cavitating flow inside the inducer,a series of experiments are performed based on the visualization experimental platform.The macroscopic performance,cavitation development and cavitation instabilities of the inducer pump with different inlet gas volume fractions are investigated.It is found that the head breakdown occurred earlier at larger inlet gas volume fractions.Additionally,the noncondensable gas is entrained in leakage flow vortices and backflow vortices,resulting in significant extensions of leakage flow vortex cavities and backflow vortex cavities,under larger inlet non-condensable gas entrained condition.With small cavitation numbers(Φ=0.083,σ=0.090 ,and Φ=0.071,σ=0.068),the non-condensable gas provides extra cavitation compliance to the cavity and therefore suppresses the cavitation surge.