Study on the Hydrodynamic Evolution Mechanism and Drift Flow Patterns of Pipeline Gas–Liquid Flow

Abstract

The hydrodynamic characteristic of the multiphase mixed-transport pipeline is essential to guarantee safe and sustainable oil–gas transport when extracting offshore oil and gas resources. The gas–liquid two-phase transport phenomena lead to unstable flow, which significantly impacts pipeline deformation and can cause damage to the pipeline system. The formation mechanism of the mixed-transport pipeline slug flow faces significant challenges. This paper studies the formation mechanism of two-phase slug flows in mixed-transport pipelines with multiple inlet structures. A VOF-based gas–liquid slug flow mechanical model with multiple inlets is set up. With the volumetric force source term modifying strategy, the formation mechanism and flow patterns of slug flows are obtained. The research results show that the presented strategy and optimization design method can effectively simulate the formation and evolution trends of gas–liquid slug flows. Due to the convective shock process in the eight branch pipes, a bias flow phenomenon exists in the initial state and causes flow patterns to be unsteady. The gas–liquid mixture becomes relatively uniform after the flow field stabilizes. The design of the bent pipe structure results in an unbalanced flow velocity distribution and turbulence viscosity on both sides, presenting a banded distribution characteristic. The bend structure can reduce the bias phenomenon and improve sustainable transport stability. These findings provide theoretical guidance for fluid dynamics research in offshore oil and gas and chemical processes, and also offer technical support for mixed-transport pipeline sustainability transport and optimization design of channel structures.

Cooling and Multiphase Analysis of Heated Environmentally Friendly R152A (C2H4F2) Fluid Coming from the Production Process According to Nist Indicators

“…While existing research has explored aspects such as CFD-DEM simulations for high shear flow [19], optimizing mixing tanks [20], and multiphase flow in pipelines [21,22], a detailed analysis of R152a's performance and cooling capacity under varying operating conditions remains a gap in knowledge.…”

Choosing the Most Suitable Working Fluid for a CTEC

“…Yan focused on mixed-transport pipelines, using a VOF-based model to analyze slug flow formation. Meanwhile, Zheng [16] explored slug flow in marine pipelines, employing a VOF-PLIC-based model to uncover periodic flow characteristics and the impact of gas-phase velocity changes. These studies have provided valuable insights for optimizing pipeline designs and mitigating vibrations.…”

Design and Experimental Tests of a Four-Way Valve with the Determination of Flow Characteristics for Building Central Heating Installations Using Solid Modeling

“…During the heating mode, the compressor's task is to pump the refrigerant into the exchanger of the cooling/heating system, in which the condensation process takes place, i.e., where heat is released. In the cooling mode, the direction of the process described above is reversed, so the condenser device in the heating mode functions as an evaporator, which means that the heat is supplied to the lower source, which is the external environment [1]. The heating/cooling mode is changed using a four-way valve, which changes the flow direction thanks to a mechanism (slipper) mounted at the intersection of the cooling/heating system.…”

“…Computational fluid dynamics is a type of computer simulation that can be used to predict the behaviors of various factors. The software enables simulations in 2D, 3D and axisymmetric 2D and can be used to mesh the model in an unstructured manner, both at the inlet, outlet, and bends, ensuring mesh quality within a computationally acceptable range, and ensuring that the mesh quality meets computational accuracy requirements [1,2]. The model also calculates the time evolution of solutions to discrete or continuous equations for transport properties related to pressure, velocity vectors, and temperature distribution in free space or around solid objects.…”