离心泵平衡腔液体压力的计算与验证

针对开平衡孔双密封环叶轮离心泵的平衡腔液体压力计算问题，基于液体通过叶轮平衡孔和后密封环间隙的泄漏量相等，引入了压力系数p和比面积k2个无因特征参数，推导出了平衡腔液体压力计算模型，其关系曲线为p= f (k )的无因次曲线，并给出了待定系数 a、b 的计算方法。在3BA-6泵上，取与计算相同的叶轮平衡孔直径进行了试验验证。结果表明，在泵设计工况下平衡腔液体压力的试验与理论无因次曲线较为一致，验证了平衡腔液体压力计算模型的正确性与可行性。该研究可为开平衡孔双密封环叶轮离心泵轴向力计算提供基础理论。

Calculation and validation of fluid pressure of balance cavity in centrifugal pump

Abstract: In the design of a centrifugal pump, the double seal ring impeller with the balance hole is the main methods of balancing axial thrust. The cover force produced by the pressure difference in the balance cavity region was the main part of axial thrust. A study on the calculation method of fluid pressure of the balance cavity in the impeller has important significance for the accurate calculation of the axial thrust. In order to solve the fluid pressure calculation of the balance cavity in the impeller, the two dimensionless characteristic parameters about specific areaand pressure coefficientwere introduced. Under the condition of the fluid leakage in the balance hole and the back seal ring clearance at the impeller was equal, a calculation model of fluid pressure in the balance cavity was derived. The dimensionless curve of the calculation model was, and an undetermined coefficient a and b in calculation method was introduced. For the 3BA-6 pump, under the condition of the different diameter of the balance hole, the theoretical dimensionless curves of the fluid pressure in the balance cavity at design point were obtained. To illustrate the problem, under the condition of the same pump structure, a verification experiment by taking the same diameter of balance hole as the calculation was conducted. The fluid pressure of the back seal ring outlet and impeller inlet at the design point was measured, so the experiment dimensionless curve was obtained. Research showed that, the experiment dimensionless curve and the theoretical dimensionless curve on the fluid pressure in the balance cavity at the design point were coincident, and the test curve above the theoretical curve, but when 0.5, was maximum between the experiment dimensionless curve and the theoretical dimensionless curve, the maximum absolute error was 0.049. The result proved that the calculation model of fluid pressure in the balance cavity was correct and feasible. For a centrifugal pump of double seal ring impeller with a balance hole, the specific expressions on the calculation model of fluid pressure in the balance cavity by calculating was obtained. Furthermore, the pressure difference of the two sides of the impeller back cover and the cover force produced by the pressure difference in balance cavity region can be calculated.