离心泵后泵腔内液体压力数值分析与验证

离心泵轴向力的大小与泵腔内压力分布密切相关,而试验测量轴向力成本较高,因此采用数值模拟展开泵腔内压力分布规律研究,并提出简便的试验测量轴向力方法显得格外必要。利用数值模拟计算,在0.6 Q_(sp)~1.2Q_(sp)工况下,研究离心泵后泵腔压力沿轴向、径向、切向分布规律,绘制后泵腔压力在0°、90°、180°、270°及压力均值沿径向分布曲线,得出后泵腔轴向力大小,推导两种近似计算泵腔轴向力公式,提出简便的试验测量泵腔轴向力方法,并将后泵腔压力模拟结果与试验结果对比,验证模拟结果的真实可靠性。结果表明:同一流量工况点,后泵腔压力沿轴向保持不变,沿径向随半径增大而增大。流量越大,后泵腔压力沿切向分布越具有轴对称性,沿径向增大越均匀。后泵腔轴向力两种公式计算结果与数值计算结果相对误差极小,后泵腔区域压力均值与其径向几何中心处压力均值大小相等。在试验测量离心泵泵腔轴向力时,只需要测量泵腔沿180°径向中心处压力值,便可近似求得泵腔区域轴向力大小。

Numerical Analysis and Validation of Fluid Pressure in the Back Chamber of Centrifugal Pump

The axial thrust of a centrifugal pump and the pressure distribution in pump chamber are closely related. The cost of experimental measurement is high on axial thrust.Therefore, it is particularly necessary that the research on the rule of pressure distribution in the chamber of centrifugal pump is conducted by numerical simulation and the simple experimental measurement method of axial thrust is put forward. Under the condition of 0.6Qsp-1.2Qsp, the research on the rule of the axial, radial and tangential distribution of pressure in the back chamber of centrifugal pump is conducted by numerical simulation. The pressure of axial center in the back chamber along four different angles and the mean pressure along radial distribution curves are drew. The value of thrust force is calculated and two formulas are derived. A simple and convenient test measurement method of axial thrust in the chamber is put forward. Numerical and experimental results of pressure are compared to verify the reliability of the numerical method.The results show that the pressure increases along radial direction in the back chamber, while the change of its value is negligible along axial direction at the same flow condition.The distributional of the pressure difference gradually decreases from 0.6Qsp to 1.2Qsp along tangential and radial direction. The pressure is parabolic distribution along 90° radial direction when the flow rate is less than design flow condition. The pressure is axisymmetric along tangential direction and it increases along radial direction when the flow rate is larger than design flow condition.The relative errors of axial thrust among two formulas and numerical calculation are little about thrust force in the back chamber. The average value of region pressure is equal to the pressure on the geometric center. When the experimental measurement is carried out to get the axial thrust in the chamber, the data is approximately equal to the measurement results of the pressure along 180° radial direction on the geometric center.