Pressure Fluctuation Characteristics Of Mixed-Flow Pump Under Near Stall Condition

Abstract

When the rotating stall occurs in a mixed-flow pump, the periodic generation and disappearance of the stall core often cause unstable pressure pulsation. Based on the k-ε turbulence model, the time domain and frequency domain responses of the pressure fluctuation of the mixed-flow pump with 3 kinds of different flange clearances are studied. The results show that the time-domain curves of pressure fluctuation at each monitoring point show periodic changes near stall condition, but the peak and trough characteristics of impeller rotation are not obvious. There is a large phase difference between adjacent monitoring points, accompanied by a strong pressure drop. When the flange clearance is 0.5 mm and 0.8 mm, the time domain curve of pressure fluctuation has 2 wave troughs in one cycle. In the near stall condition, the main frequency of pressure fluctuation at 3 monitoring points in the same channel is 0.2 times the rotational frequency, i.e. stall frequency. In addition, the main frequency amplitude in the middle of the outlet is the largest, and the larger the gap is, the larger the main frequency amplitude is.