Effect of the Valve Core Lift on the Internal Flow Characteristics of an Electronic Unit Pump
The internal cavitation flow characteristics and flow capacity of electronic controlled unit pumps with different valve core lift were calculated and studied based on the three-dimensional numerical calculation model validated through visual experiments.The results show that as the pressure differential increases,cavitation first appears in the throttling section and then downstream.Flow separation leads to cavitation in the throttling section,and the entrainment effect of the jet leads to cavitation downstream.Moreover,under all inlet pressures,the larger the valve core lift,the greater the critical cavitation number.When the total vapor volume fraction in the throttling section reaches 2％,choking flow happens and the flow coefficient decreases.Before the occurrence of choking flow,the flow coefficient varies lightly with pressure differential.After the occurrence of choking flow,the enhanced cavitation with the increase of pressure differential in the throttling section leads to an increase in velocity coefficient,but a greater decrease in area coefficient,resulting in a smaller flow coefficient.After the vapor volume in the throttling section reaches the maximum,the larger the valve core lift,the smaller the flow coefficient.When the valve core lift is greater than 0.10 mm,the flow coefficient changes very lightly with the lift.
electronic unit pumpvalve core lifthigh pressurecavitationflow capacity
NETL
NSTL
万方数据
