Flow model for side chambers of centrifugal pumps considering impeller flow slip
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摘要:
为研究离心泵盘腔内外特性,将离心泵盘腔三维流动简化为动静腔一维流动,基于动量守恒方程和径向连续方程,构建了动静腔流动微分方程;积分该方程并应用到盘腔中,引入密封件阻力系数,考虑叶轮流动滑移,修正泵势扬程公式,建立了离心泵叶轮⁃盘腔⁃密封环⁃平衡孔回路的自封闭流动模型。提出了内外迭代相结合的求解方法,实现了离心泵盘腔流动快速计算。通过与盘腔压力测量结果对比表明:使用Stodola叶轮流动滑移系数的盘腔流动模型比使用Wiesner叶轮流动滑移系数的盘腔流动模型的计算精度提高了约3.5%。盘腔流动模型结果表明:泵工况从小流量调节至大流量,容积效率逐渐提高,盖板推力略微逐渐增大。该方法及结论为离心泵盘腔内外特性计算提供参考。
Abstract:To study the internal and external characteristics of the side chambers of centrifugal pumps,the three⁃dimensional flow in the side chambers of centrifugal pumps was simplified into one⁃dimensional flow in the rotor⁃stator cavities,and then the differential equation for the flow in the rotor⁃stator cavities was established based on the momentum conservation equation and the radial continuity equation;by integrating this equation,applying it to the side chambers of centrifugal pumps,and introducing the resistance coefficients of the sealing parts,the impeller flow slip was considered,the pump potential head formula was modified,and a self⁃closure flow model from the impeller to side chambers to seals to balance holes in the centrifugal pumps was established.A solution method combining internal and external iterations was proposed,which realized the instant calculation of the flow in the side chambers of centrifugal pumps.Compared with the pressure measuring results of the centrifugal pump side chambers,the flow model using the Stodola impeller flow slip coefficient was more accurate by 3.5% than the flow model using the Wiesner impeller flow slip coefficient.The results of the flow model of disk cavities showed that:as the pump working condition was adjusted from partial flow rate to overflow condition,the volumetric efficiency gradually increased,and the thrust of the impeller shrouds gradually increased slightly.The method and conclusions provide references for calculations of the internal and external characteristics of the side chambers of centrifugal pumps.
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Key words:
- centrifugal pump /
- side chambers /
- flow model /
- impeller flow slip /
- thrust on shrouds /
- volumetric efficiency
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