叶轮开孔参数对气液两相高速离心泵的影响

Influence of impeller perforation parameters on performance of high-speed gas-liquid centrifugal pump

为保持高速离心泵在气液两相条件下的性能稳定性,采用CFD数值模拟方法探究不同孔径和位置叶轮开孔对高速离心泵的性能影响。结果表明:开孔泵的性能趋于稳定,随着入口含气率的增大,开孔泵的扬程逐渐降低。而原始无孔泵扬程随着入口含气率的增大而显著下降。因此,在入口含气率较大的情况下,开孔可以提高高速离心泵的性能;当入口含气率不足时,有孔泵的性能不如原始无孔泵,扬程随着孔径的增大而减小。当孔径为3.5 mm时,扬程衰减超过18%,因此孔径不应>3 mm;随着开孔孔径的增大,叶轮中的气体体积减小,而孔径越大,泵内的水力损失越大。因此在选择孔径时,必须在叶轮中的气体体积和泵的水力损失之间进行权衡;开孔的径向位置值越小,孔越靠近叶轮中心,水力损失越大;开孔的径向位置值越大,叶轮中气体体积就越大,在选择开孔的径向位置时,仍然需要权衡。对于所研究的高速离心泵,仿真结果表明,径向位置为14 mm和孔径为2 mm的选择是可取的,可以很好地平衡叶轮中气体体积和水力损失。

In order to maintain the performance stability of high-speed centrifugal pumps under gas-liquid two-phase conditions,CFD numerical simulation was used to investigate the effect of different aperture diameters and positions of impeller openings on the performance of high-speed centrifugal pumps.The results show that the performance of aperture pumps tends to be stable,with the inlet gas content increases,the head of aperture pump gradually decreases.While the head of the original non-porous pump decreases significantly with the increase of inlet gas content.Therefore,in the case of large inlet gas content,opening hole can improve the performance of high-speed centrifugal pump.When the inlet gas content is not enough,the performance of perforated pump is not as good as the original non-perforated pump,and the head decreases with the increase of perforated diameter.When the apertures are 3.5 mm,the head decay is more than 18%,so the apertures are not more than 3 mm.With the increase of aperture diameter,the volume of gas in impeller decreases,and the larger the aperture diameter,the greater the hydraulic loss in the pump.Therefore,when choosing the aperture,the gas volume in the impeller and the hydraulic loss of the pump must be traded off.The smaller the value of radial position of open aperture,the closer the aperture is to the center of the impeller,the greater the hydraulic loss.The larger the value of radial position of open aperture,the larger the volume of gas in the impeller,and there is still a trade-off to be made when choosing the radial position of the open aperture.For the studied high-speed centrifugal pump,the simulation results show that the choice of radial position of 14 mm and aperture diameter of 2 mm is desirable because it can well balance the gas volume and hydraulic loss in the impeller.