高压离心泵进口压力与轴向力特性的关联性

Association between Inlet Pressure and Axial Force of a High Pressure Centrifugal Pump

高压离心泵进口压力是影响其轴向力大小的因素之一。选取某高压半开式叶轮离心泵在0.8~1.2 Qd的工作区域,在对外特性计算结果进行试验验证的基础上,详细分析进口压力为7.8~8.2 MPa的5种条件下,叶轮盖板外侧轴向力F1、叶轮盖板内侧轴向力F2、叶片轴向力F3、轴端轴向力F4的分布规律,并绘制各轴向分力增加率与流量变化曲线。揭示设计流量1.0 Qd时,叶轮盖板内、外侧壁面及叶片工作面、背面压力分布特征,得出叶轮盖板外侧壁面轴向力近似计算方法。研究表明:同一流量工况时,进口压力越大,叶轮盖板外侧轴向力F1、叶轮盖板内侧轴向力F2、叶片轴向力F3、轴端轴向力F4均越大,离心泵总轴向力F越小。同一进口压力时,轴端轴向力F4不受流量变化影响,但流量越大,离心泵总轴向力F越小。因此,本研究对减小高压离心泵轴向力,提高其运行稳定性具有重要的指导意义。

The inlet pressure of a high-pressure centrifugal pump affectsits axial force.A high-pressure and semi-open impeller centrifugal pump was selected in the working area of 0.8~1.2 Qd.Based on the comparison of external characteristics of numerical calculation with the experimental result,the distribution patterns of axial forces(F1,F2,F3 and F4)were analyzed in detail when the inlet pressure was 7.8,7.9,8.0,8.1 and 8.2 MPa respectively.The change curve of the increase rate of each axial force was drawn.At the designed flow rate of 1.0 Qd,the pressure distribution characteristics of the inner and outer walls of the impeller cover,the working face of the blade and the back of the blade were demonstrated.The approximate calculation method for axial force on the outer wall of the impeller cover was obtained.The research results show that at the same flow rate,the larger the inlet pressure is,the larger the axial forces(F1,F2,F3 and F4)are,and the smaller the total axial force F of the centrifugal pump is.At the same inlet pressure,the axial force F4 is not affected by flow change.The larger the flow rate,the smaller the total axial force F of the centrifugal pump.Therefore,this research can provide certain guidance for reducing the axial force of the high-pressure centrifugal pump and improving its operation stability.