Numerical modeling of dynamic characterics for combined valves in multiphase pump

This research presents theoretical analysis and numerical simulation of combined valves' dynamic characteristics in reciprocating oil-gas multiphase pump. Based on the mathematical model describing valves' motion, a geometric model of pump cavity and combined valves is put forward for numerical simulation in multiphase pump. The simulation is conducted by computational fluid dynamics (CFD) method with its dynamic grid technique. The motion process of suction valve and discharge valve are obtained on the basis of boundary conditions and optimized numerical approaches. And the effects of gas volume fraction (0.1∼0.9), suction pressure (0.20∼0.40 MPa) and discharge pressure (1.0∼3.0 MPa) on valves' motion are reported. The results of pressure distribution, and valves' lift and velocity show that valve plates may cling or rebound and then vibrate after reaching the lift limiter, and the lag angle of one cycle remains 3° under different working conditions. The study could lay theoretical foundation for the design of new type of multiphase pump.