复合叶轮改善双吸式离心泵空化性能研究

Improvement of Cavitation Characteristics of Double Suction Centrifugal Pump with Compound Impeller

摘要:

针对双吸式离心泵在大流量工况下容易遭到汽蚀破坏，运行可靠性差的问题，采用长短叶片复合叶轮对双吸泵的空化性能进行改善研究。选用SST k—ω湍流模型及Rayleigh—Plesset空化模型，对常规叶轮和复合叶轮双吸泵进行了全流道三维定常数值计算，并与试验结果进行了对比，对叶轮内部流场进行了分析。研究表明，长短叶片复合叶轮能够显著改善双吸泵的空化性能，降低必需空化余量，减小空化区的范围，改善叶片表面压力分布及叶轮内部流动状况，在大流量工况下改善效果更为明显。

Abstract:

In the large flow conditions, the double suction centrifugal pump is susceptible to cavitation damage and has bad operation reliability. Aiming at the problem, a compound impeller with long and short blades was used to improve the cavitation characteristics. By using the shear stress transport (SST) k—ωturbulence model and Rayleigh—Plesset cavitation model, numerical simulation of the double suction centrifugal pump with a conventional impeller and a compound impeller were carried out respectively. The simulation results in the form of characteristic curves were compared with the experimental data, and the internal flow field was analyzed. The result showed that in the large flow conditions, critical net positive suction of the pump with a compound impeller was reduced. Also, the compound impeller can reduce the vapour distribution, change the pressure distribution and improve the dropping flow and backflow. Moreover, the better effect would be achieved under large flow condition.