Numerical simulation and experimental study on cavitation of micro high-speed fuel pump
Based on SST k-ω turbulence model and ZGB cavitation model were used to numerically simulate the internal flow with and without cavitation under different operating conditions of a certain type of micro high-speed fuel pump.The vibration accelerations in X,Y,and Z directions under different working conditions and heights were collected,and the vibration characteristics with and without cavitation were analyzed.The results show that changes in flow rate,rotational speed,and height have a significant impact on the cavitation characteristics of micro high-speed fuel pumps.At rated speed,as the inlet pressure of the fuel pump decreases,cavitation first appears on the inside of the pump inlet elbow and the back of the impeller blade,further expanding to the entire impeller flow channel,which basically blocks the flow.The gas content in the impeller also increases from less than 5%to about 70%.In both simulation and visualization,the initial position of the bubble can be observed to be at the elbow,which then diffuses to the suction elbow and gradually increases,forming a clear gas-liquid boundary line and ultimately leading to complete flow interruption.When cavitation occurs,there is a significant vibration in each axial direction at twice the blade frequency,and the sequential increasing trend is Y,X,and Z axes.As the height increases,the degree of cavitation intensifies,and the vibration spectrum in all directions changes,with the maximum peak values all showing a decreasing trend,but triggering higher frequency vibration signals.The amplitude variation law of vibration power spectral density corresponds to the cavitation development degree,which can be used as the characterization of the cavitation degree in the pump.This study provides a theoretical basis for cavitation discrimination and cavitation flow control of micro high-speed fuel pumps.
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