蜗壳式混流泵轴向力的数值计算与试验验证

以某型号蜗壳式混流泵为例,构建基于压力分布理论的无泄漏模型,提出并构建基于泵腔体内真实流动的泄漏模型,分别对2种模型在0.03Q_opt~1.20Q_opt工况下的流动进行仿真模拟,计算得出其轴向力随流量变化的曲线,并将数值计算结果、理论计算结果与试验结果进行对比,详细分析了不同轴向力计算方法的准确性及泄漏流动对轴向力的影响.结果表明:叶轮盖板后腔压力是混流泵产生轴向力的主要因素,泄漏流动可以有效降低其内部压力;基于无泄漏模型的数值计算法和理论计算法均建立在盖板腔内无泄漏的假设之上,忽略了泄漏流动对轴向力的影响,导致计算结果存在较大偏差,2种计算方法的最大误差分别为25%和44%.基于泄漏模型的轴向力数值计算数据与试验数据比较接近,最大误差在10%以内,计算精度大幅提升,说明基于泄漏模型的轴向力数值计算方法具有更高的准确性和可行性.

Numerical calculation and experimental verification for axial force on mixed flow pump

A volute-type mixed flow pump was taken as an example to construct a leak-free model based on pressure distribution theory.A leakage model based on the true flow of the pump cavity was proposed and constructed.The flow of the two models under the conditions of 0.03Qopt-1.20Qopt was simulated.The curves of the respective axial forces with the flow rate were calculated,and the numerical calculation results,theoretical calculation results and experimental results were compared.Meanwhile,the accuracy of different calculation methods and the influence of leakage flow on axial forces were analyzed in detail.The results show that the back cavity pressure of the impeller cover is the main factor for the generation of axial force,and the leakage flow can effectively reduce its internal pressure;the numerical calculation method based on the leak-free model and the theoretical calculation method are both based on the assumption that there is no leakage in the chamber of the cover,ignoring the inf-luence of leakage flow on axial force,leading to a large deviation between the calculation value and the test value.The maximum errors of the two calculation methods are 25%and 44%respectively;the numerical calculation data of axial force based on the leakage model are close to the test data,and the maximum error is within 10%.The calculation accuracy has been greatly improved,indicating that the numerical calculation method of axial force based on the leakage model has higher accuracy and feasibility.