蜗壳喉部面积对离心泵非定常特性的影响

Research on the Influence of Volute Throat Area on Unsteady Characteristics in a Centrifugal Pump

为研究蜗壳喉部面积对离心泵非定常特性的影响,针对同一离心泵叶轮,设计匹配4种不同喉部面积的蜗壳,并采用数值计算方法对泵内流非定常流动进行计算。结合面积比原理,分析了喉部面积对泵性能、径向力以及压力脉动的影响规律。结果表明:喉部面积对离心泵水力性能影响显著,设计工况下,随着喉部面积的减小,扬程和效率逐渐降低;受喉部面积影响,不同工况叶轮所受径向力大小不同且具有极小值,但极小值所对应的工况点有所不同;合理的喉部面积能有效降低泵内的压力脉动水平,随着喉部面积减小,泵内压力脉动水平增加,而当增加喉部面积时,压力脉动水平降低。通过分析蜗壳不同喉部面积对离心泵性能的影响,可为低噪声离心泵面积比设计提供参考。

For a given impeller,four pumps with different volute throat areas,were calculated based on numerical simulation method.Unsteady flow characteristics of the pumps were obtained.The influences of throat area on hydraulic performance,radial force and pressure pulsation were discussed.Results show that throat area has a great effect on the pump hydraulic performance.The head and hydraulic efficiency decrease with throat area decreasing at nominal flow rate.The radial forces of four impellers differ significantly at various flow rates,which would reach a minimum value.But the corresponding flow rates of the minimum points are different.The reasonable throat area could effectively reduce the amplitude of pressure pulsation,and it would increase with the throat area decreasing.Meanwhile,pressure pulsation energy decreases with the throat area increasing.The obtained results would provide some supports for low noise centrifugal pump design considering different throat areas.