不同几何形状环形槽对高速诱导轮空化性能的影响

Influence of annular grooves with different geometric structureson high-speed inducer cavitation performance

为进一步探究提升航空航天用高速离心泵空化性能的方法,研究环形槽几何形状对高速诱导轮空化性能的影响,设计了矩形、单曲率、双曲率3种不同几何形状的环形槽.使用原模型泵的外特性和空化性能试验验证了数值模拟方法的有效性,对不同方案进行数值模拟,分析不同几何形状环形槽对高速诱导轮离心泵空化性能、流道内能量分布以及诱导轮入口流态的影响.结果发现:在高速诱导轮上游设置环形槽可以降低泵的必需汽蚀余量,其中单曲率槽可以使离心泵的必需汽蚀余量降低得更多,为27.0%,双曲率槽和矩形槽分别使必需汽蚀余量降低14.7%和5.4%;环形槽可以减小叶顶间隙回流对上游主流的影响,诱导轮叶片上湍动能分布更加均匀,诱导轮流道内的压力明显提升;回流在单曲率槽中的过渡更为平滑而对周向旋涡的抑制作用较弱,矩形槽和双曲率槽吸收壁面旋涡的能力更强,可以削弱上游不对称涡向诱导轮流道的发展和影响.

In order to further explore ways to improve the cavitation performance of high-speed centri-fugal pumps used in aerospace,and to study the effect of annular groove geometry on the cavitation performance of high-speed inducer,three different geometric shapes of annular grooves,namely rectangular,single curvature and double curvature,were designed.The effectiveness of the numerical simulation method was verified by the hydraulic characteristics and cavitation performance test of the original model pump.The numerical simulation of different schemes were carried out to analyze the influence of different geometric annular grooves on the cavitation performance,energy distribution in the flow channel and the inlet flow pattern of the inducer in the high-speed inducer centrifugal pump.The results show that setting the annular groove upstream of the high-speed inducer can reduce the neces-sary cavitation margin of the pump.Among them,the single-curvature groove can reduce the necessary cavitation margin of the centrifugal pump by 27.0%,and the double-curvature groove and the rectangular groove reduce the necessary cavitation margin by 14.7%and 5.4%,respectively.The annular grooves can reduce the influence of the tip clearance backflow on the upstream mainstream,the turbulent kinetic energy distribution on the inducer blade is more uniform,and the pressure in the inducer channel is significantly improved.The transition of the back flow in the single-curvature groove is smoother and the suppression of the circumferential vortex is weaker.The rectangular groove and the double-curvature groove have a stronger ability to absorb the wall vortices,which can weaken the development and influence of the upstream asymmetric vortex to inducer channel.