中文摘要：

通过数值模拟和试验,研究了叶轮口环间隙对离心泵性能的影响。为准确计算离心泵的扬程和效率,设计了包含前后泵腔在内的全流场模型。基于RNG k-ε湍流模型,建立了3种口环方案,重点从湍动能、涡量和径向力角度,分析了口环间隙对离心泵全流场水力效率和机械效率的影响。结果表明：当口环间隙值减小时,离心泵的扬程和总效率均增大。究其原因有：叶轮内能量耗散降低;叶轮进口处二次流对主流的冲击作用减弱;离心泵的偏心涡动减弱;前腔泄漏量减少。通过对3种口环方案的综合比较,最终确定叶轮口环采用方案I,效率最高而且满足工程实际应用的需要。

英文摘要：

The effect of clearance of impeller wear-rings on the performance of a centrifugal pump was investigated numerically and experimentally.The whole flow field model including front and back shrouds of pump was designed so as to accurately calculate the head and efficiency of the centrifugal pump.Based on RNG k-ε turbulence model,three wear-rings schemes were established,and the effects of clearance of impeller wear-rings on the hydraulic efficiency and mechanical efficiency of the centrifugal pump was analyzed,chiefly from the turbulent kinetic energy,vorticity and radial force angles.According to the results,it can be drawn that the head and total efficiency of the centrifugal pump increase as the clearance value of wear-rings narrows.The following reasons may account for it： the energy dissipation decrease within the impeller;the impact of secondary flow at the inlet of impeller on the mainstream weakens slowly;the eccentric whirl of centrifugal pump is dampened;the front shroud leakage diminishes.Finally,the first wear-ring scheme of impeller is adopted after comprehensive comparison of these three wear-ring schemes,because its efficiency is highest and it satisfies the requirements of the engineering application.