Numerical simulation of suction and discharge valves' motion in reciprocating waterflooding pump

Abstract

The suction and discharge valves are the key hydraulic and wearing components in the reciprocating waterflooding pump, which have a significant influence on the operation stability and efficiency of pump. To investigate the valves' dynamic working in the working processes, the numerical simulation of reciprocating waterflooding pump was carried out by Computational Fluid Dynamics (CFD) method. Based on the force characteristic on the valve plate, User Defined function and dynamic grid were adopted to define and update the valves' dynamic parameters with the reciprocating motion of piston. The effects of spring stiffness coefficient and lift limit height on the transient motions of valves were investigated for the reciprocating waterflooding pump. The results show that the suction and discharge valves open or close in a short period. However, their motions lag behind the stroke when the piston reaches the left or right end point, especially for the discharge valve, which will lead to the larger impact effect and flow loss. Under various working parameters, the striking velocity on the lift limiter or seat is not always equal to the maximum velocity, and the valve plate is easily to vibrate in the suction process due to the pressure fluctuation and flow instability. The valve lifts, characteristic velocities and lag angles change in different ways with these three parameters, and the lag heights of discharge valve could exceed 3 times those of suction valve. The simulation results would provide a theoretical basis for the design of high-efficiency oilfield waterflooding pump.