Numerical Simulation Of Flow Characteristics Of Low Liquid Loading Gas-liquid Two-phase Flow In Inclined Pipes

In the production and transportation process of oil and natural gas,low liquid loading gas-liquid two-phase flow widely exists.This special gas-liquid two-phase flow is commonly found in wet-gas pipelines of gathering and transportation and inclined natural gas wellbores.China has a vast territory,and most oil and gas pipelines are distributed in areas with large topographic relief.Due to the large transportation volume and long transportation distance,in order to save costs and improve transportation efficiency,pipelines are also developing towards large pipe diameters and high pressure.This puts forward new requirements for the study of gas-liquid two-phase flow.In this paper,a three-dimensional numerical model of an inclined pipe with an inclination angle of 2 °,an inner diameter of 155.7 mm,and a length of 5.57 m was established using the modeling software Spaceclaim.The model was meshed using ICEM,and the steady-state calculation was performed using CFD software ANSYS Fluent.The effects of the superficial flow rates of the gas and liquid phases,as well as the pressure gradient and liquid holdup of the low liquiding gas-liquid two-phase flow in the high pressure inclined pipe,were analyzed,The transition of flow patterns within the operating range was explored.The results show that the gas-liquid two-phase flow patterns within the operating range of this article are mainly distributed in the stratified flow and annular flow regions.The Beggs-Brill model,Mukherjee-Brill model,and ARS model were selected for comparative analysis.The applicability and operating conditions of the three models were discussed.The results showed that the root mean square error of the three models for predicting pressure gradients was mostly within ± 20% of the data points.The accuracy of the Beggs-Brill correlation for predicting pressure gradients in the pipe was better than the Mukherjee-Brill correlation and ARS model.The prediction and calculation error of ARS model for liquid holdup is within ±10%.In this paper,a numerical model has been established to study the flow characteristics of low liquiding gas-liquid two-phase flow in a inclined pipes within a relatively large diameter,under high pressure,exploring the applicability of the mechanistic model,providing a data reference for the study of low liquiding content gas-liquid two-phase flow in inclined pipes,which has practical significance.