Investigation of the droplet-carrying characteristics of the gas flow in multiphase pump valves

Abstract

In high gas-bearing conditions, the oil phase—in the form of droplets— often enters the reciprocating multiphase pump via the valves. Understanding the droplet-carrying characteristics of the gas flow is important for determining the transport capacity and stability of multiphase pump valves. In this paper, the turbulent gas flow and droplet movement behaviors in three typical valves of the reciprocating multiphase pumps were studied mainly by the theoretical analysis, the numerical simulation of computational fluid dynamics (CFD) and the verification test of particle image velocimetry (PIV). The steady and transient droplet trajectories, concentration distributions, and passing capacities were comprehensively studied with different valve openings, Reynolds numbers, and two-phase slip conditions. The results show that the ball valve performs steadily during the transport of the small to large droplets, while the cone valve and the disk valve perform well when transporting the small droplets with d≤250μm and the medium-sized droplets with 300μm≤d≤600μm under the initial conditions, respectively. Finally, the correlations of the volume mean diameter (dvm) of the droplets successfully passing through the cavities were proposed for the three valves. The results of this study are beneficial to help optimize and design new high-efficiency multiphase transport systems.