Estudo numérico do escoamento bifásico líquido-gás em uma bomba centrífuga submersa

Abstract

In the petroleum industry, artificial lifting methods are often necessary to increase the production of old oil wells. One of the most used artificial lifting methods is the electric submersible pump (ESP). ESPs are composed by several stages of impellers and diffusers that add energy to the fluid, increasing its pressure. They generally operate under multiphase flow conditions, commonly characterized by a gaseous phase and other liquid phases. This is a challenge in the use of ESPs because such equipment is not designed to operate under the presence of the gas. Therefore some inconvenient operational conditions occur from this fact. It is observed a diminution of the system performance and an abrupt drop on the pressure gain provided by the pump. This phenomenon is called surging. Moreover, ESPs systems are also subject to a significant restriction on the optimal pump operational range when handling multiphase flows. There are several approaches to study this problem. In this work, it is considered a numerical approach using computational fluid dynamics with the aid of the commercial software ANSYS-CFX. From a computational design of the geometry of an ESP Reda GN-7000, a numerical mesh is generated and used to perform the numerical simulations. In possession of the numerical results, flow fields and performance curves are obtained. It is then carried out an analysis of how the gas phase affects the flow.