Research and Test on Mathematical Model of Pressure in Pump Cavity and Balance Cavity of Centrifugal Pump

Abstract

The pressure distribution law and calculation of impeller side cavity is one of the important topics in the pump industry, but there is no more accurate calculation method at present. On this basis, a mathematical model of pump cavity pressure distribution and balance cavity pressure under design conditions was derived in this paper. By changing the radial clearance of front and back sealing rings and the diameter of the balance hole on the same impeller, the pressure distribution of front and rear cavities and the balance cavity pressure of the pump were systematically tested by a specially designed device. In the test, the curve of pressure loss coefficient and relative radius of pump cavity under different sealing ring radial clearance was obtained, which could solve the calculation problem of the pressure distribution of front and rear pump cavities. The test curve of the relationship between flow coefficient ratio and specific surface area essentially reflected the coupling regulation effect of balance holes and the rear sealing ring on the balance cavity pressure, which could not only solve the calculation problem of the balance cavity pressure, but also provide the theoretical basis for controlling the pressure and cover force of balance cavity and select different combinations of the radial clearance of the rear sealing ring and the diameter of balance holes. The results showed that the theoretical prediction value was more consistent with the actual measured value, which proved that the proposed mathematical model has high accuracy and universality. This study provides a new way to more accurately calculate the pump cavity pressure distribution and balance cavity pressure and laid a theoretical basis for the study of impeller cover force with significant academic and application value.