Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
MECHANISTIC MODELING OF THE SURGING PHENOMENON INITIATION IN CENTRIFUGAL PUMPS OPERATING WITH GAS-LIQUID TWO-PHASE FLOW
Submission Author:
Cesar Alata , PR , Brazil
Co-Authors:
Cesar Alata, Henrique Stel, Rigoberto Morales
Presenter: Cesar Alata
doi://10.26678/ABCM.ENCIT2022.CIT22-0121
Abstract
In the oil industry, one of the most used techniques for artificial lift consist of submersible centrifugal pumps. The presence of gas in the wells gives rise to liquid-gas flow, causing a drastic degradation of the pump's performance, a condition known as surging. This occurrence significantly affects the pump production and service life, as centrifugal pumps are usually designed to operate with single-phase liquid flows. There are several studies in the literature on the phenomenon of surging, both experimental and numerical, providing valuable information for its understanding. However, attempts to obtain mechanistic models to its prediction have limitations for assessing the overall performance of the pump for different operating conditions, so their applicability is questionable. In this sense, the present study seeks to present a mechanistic model that better represents the dominant mechanisms of the surging phenomenon. The proposed model is based on the inability of a bubble to move inside the rotor at certain operating conditions. In order to obtain a simple model that avoids excessive calibration parameters, some hypotheses are considered to simplify its complexity and make it tractable. The fundamental assumption of the model for predicting the starting point of surging resides in the existence of a delay in the gas velocity in relation to the liquid such that, at some point, the bubble will tend to stop at the rotor. If this occurs, it will start a process of coalescence with other bubbles coming from the inlet, initiating the formation of pockets that, in turn, will induce the huge hydraulic losses associated with the occurrence of surging. An approach to predict the starting point of surging is proposed, in order to have a better assessment of the pump operating window without serious performance degradation. This could lead to more reliable decisions in the pump operation under gas-liquid flows, consequently improving the pump efficiency and applicability for such scenarios.
Keywords
two-phase, Surging, centrifugal pump, Mechanistic model
