多级离心泵轴向力的数值计算与试验研究

Numerical calculation and experimental study of axial force on multistage centrifugal pump

轴向力的大小及平衡问题是影响离心泵可靠性、安全性以及效率的重要因素。由于不同的经验公式计算出来的轴向力大小相差很大,因此,找到一个离心泵轴向力精确计算的方法十分必要。该文通过对离心泵轴向力的理论分析,基于Fluent商用软件,采用标准k-ε湍流模型、SIMPLE算法对多级离心泵的内流场进行数值计算,分析离心泵内部流场的静压分布规律,并通过静压积分求得轴向力大小。对模型泵进行压力分布试验,获得14组流场的压力值及流量-压力、扬程-压力曲线,从而推导计算出轴向力大小。比较数值模拟与试验结果,压力值在小流量工况下相差较大,在设计工况下接近叶轮出口处模拟压力值与试验值基本吻合;轴向力的计算结果大体一致,最大误差仅为4.6%,在允许误差范围内。研究结论为离心泵的可靠性设计提供了新的思路和方法。

The value and balance of axial forces are important factors that impact the centrifugal pump reliability, safety and efficiency. Due to calculated results of different experience formula of axial force are different, it is necessary and urgent to find a centrifugal pump axial force calculation method. Through theoretical analysis of axial forces, the flow field of multistage centrifugal pump was simulated by commercial software Fluent, which based on standard κ-ε turbulence model and SIMPLE algorithm. The static pressure distributions in centrifugal pump internal were analyzed and the axial forces were acquired by static pressure points. Through pressure distribution tests of model pump, the 14 groups of pressure value in flow field and flow-pressure, head-pressure curve were obtained, and the axial force was estimated accordingly. Comparing the numerical results and experimental results, the pressure values at small flow condition have a big difference. At the rated conditions, the pressure values at impeller outlet are basically consistent with experimental values. The simulated results of axial force closely match with the experimental ones, and the maximum error is 4.6%, within allowable error range. The research can provide new ideas and methods for reliability designs of centrifugal pumps.