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.
ARTICLE HISTORY
A numerical and experimental study was carried out to investigate the two-phase flow fields of the typical three valves used in the multiphase pumps. Under the gas volume fraction conditions in the range of 0%–100%, the three-dimensional steady and dynamic two-phase flow characteristics, pressure drops, and their multipliers of the ball valve, cone valve, and disk valve were studied, respectively, using Eulerian–Eulerian approach and dynamic grid technique in ANSYS FLUENT. In addition, a valve test system was built to verify the simulated results by the particle image velocimetry and pressure test. The flow coefficient CQ (about 0.989) of the disk valve is greater than those of the other valves (about 0.864) under the steady flow with a high Reynolds number. The two-phase pressure drops of the three valves fluctuate in different forms with the vibration of the cores during the dynamic opening. The two-phase multipliers of the fully opened ball valve are consistent with the predicted values of the Morris model, while those of the cone valve and disk valve had the smallest differences with the predicted values of the Chisholm model. Through the comprehensive analysis of the flow performance, pressure drop, and dynamic stability of the three pump valves, the disk valve is found to be more suitable for the multiphase pumps due to its smaller axial space, resistance loss, and better flow capacity.
In petroleum industry, the stability of multiphase pumping is highly disturbed by the gas' presence with high content and variable working conditions. This paper is focused on studying the whole working cycle of the novel three-cylinder double-acting reciprocating multiphase pump. Based on the theoretical analysis, the method of computational fluid dynamics (CFD) is adopted to simulate the oil–gas flow in reciprocating multiphase pump. The numerical methodology, involving multiphase model, dynamic grid technique and user defined functions (UDF), is used to deal with in the calculation. The transient flow characteristics in pump cavity are obtained, and the flow ripples of reciprocating multiphase pump are analyzed. Furthermore, the effects of different operating parameters, such as suction and discharge pressures, inlet gas volume fraction (GVFi) on the capacity, and stability of pump, are studied. The results could help to develop and optimize the high-efficiency multiphase pump system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.