Research on the Dynamic Cavitation Flow Characteristics in the Control Valve Region during the Opening Process of the Valve in an Electronic Unit Pump

In this paper, the dynamic evolution of cavitation flow in the solenoid valve area and the flow coefficients during the opening process of the valve in an electronic unit pump (EUP) are studied. Firstly, the pressures of high-pressure fuel and low-pressure fuel, the displacement curve of the control valve, and the flow image in the EUP in the period are obtained by an optical experiment. Then, setting the test results as the boundary conditions, a transient CFD simulation of cavitation flow in the valve region during the opening process including rebounds is carried out using dynamic mesh technology. Then the evolution and forming mechanism of cavitation during the process are analyzed. Cavitation is affected by the jet from the valve port which varies with the pressure differential, the geometry of the domain and the movement of the valve. By comparing with the mass flow rate, velocity coefficient, area coefficient and flow coefficient under conditions without cavitation and without rebound, it is found that cavitation can increase the velocity of the fuel, but significantly reduce the effective flow area, which finally affects the flow capacity of the EUP.