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 0.6Q_sp-1.2Q_sp, 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 0.6Q_sp to 1.2Q_sp 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.