Study on the Hydrodynamic Evolution Mechanism and Drift Flow Patterns of Pipeline Gas–Liquid Flow
Qing Yan,
Donghui Li,
Kefu Wang
et al.
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… Show more
“…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.…”
Cooling processes are responsible for a significant portion (20%) of global energy consumption and raise environmental concerns such as ozone depletion, the greenhouse effect, and high energy use. This study investigates the potential of R152a, a refrigerant with low global warming potential (GWP), as a more sustainable alternative. The performance, safety, and operational efficiency of R152a were evaluated under various conditions. Although R152a offers high performance and low GWP, its flammability necessitates caution, especially in certain mixtures. A 12-pass tube-type heat exchanger model was simulated using computational fluid dynamics (CFD) to analyze the fluid behavior within the exchanger. The pressure, density, dynamic pressure, Prandtl number, total pressure, and temperature distributions for both R152a and H2O (water) were visualized using contour plots. The simulations comprehensively examined the fluid behavior inside and outside the heat exchanger. The results revealed the influence of the temperature on the internal dynamic pressure and density of R152a. Compared with R134a, R152a demonstrated superior performance but a lower coefficient of performance (COP) than R32. Studies also suggest that R152a exhibits lower irreversibility in Organic Rankine Cycle (ORC) systems than R245fa. These findings suggest that R152a holds promise for future refrigeration systems, as supported by existing research on its performance and compatibility. One study focused on optimizing the heat exchanger performance by maximizing the heat capacity and minimizing the pressure drop. This study employed a parallel-flow heat exchanger with R152a as the coolant for the hot process water. The temperature changes, pressure drops, and resulting energy efficiency and thermal performance of both fluids were analyzed. The results highlight the distinct energy efficiencies and thermal performance of the employed fluids.
“…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.…”
Cooling processes are responsible for a significant portion (20%) of global energy consumption and raise environmental concerns such as ozone depletion, the greenhouse effect, and high energy use. This study investigates the potential of R152a, a refrigerant with low global warming potential (GWP), as a more sustainable alternative. The performance, safety, and operational efficiency of R152a were evaluated under various conditions. Although R152a offers high performance and low GWP, its flammability necessitates caution, especially in certain mixtures. A 12-pass tube-type heat exchanger model was simulated using computational fluid dynamics (CFD) to analyze the fluid behavior within the exchanger. The pressure, density, dynamic pressure, Prandtl number, total pressure, and temperature distributions for both R152a and H2O (water) were visualized using contour plots. The simulations comprehensively examined the fluid behavior inside and outside the heat exchanger. The results revealed the influence of the temperature on the internal dynamic pressure and density of R152a. Compared with R134a, R152a demonstrated superior performance but a lower coefficient of performance (COP) than R32. Studies also suggest that R152a exhibits lower irreversibility in Organic Rankine Cycle (ORC) systems than R245fa. These findings suggest that R152a holds promise for future refrigeration systems, as supported by existing research on its performance and compatibility. One study focused on optimizing the heat exchanger performance by maximizing the heat capacity and minimizing the pressure drop. This study employed a parallel-flow heat exchanger with R152a as the coolant for the hot process water. The temperature changes, pressure drops, and resulting energy efficiency and thermal performance of both fluids were analyzed. The results highlight the distinct energy efficiencies and thermal performance of the employed fluids.
“…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.…”
This study aims to explore additional fluids beneficial for coastal thermal energy converter (CTEC) operation. Ammonia’s thermodynamic properties, characterized by higher condensation temperatures and pressures, demand significantly elevated operating pressures, resulting in a substantial energy load for efficient operation. Thus, exploring alternatives such as R134a becomes crucial, particularly considering its potential as a better working fluid for power generation in a Rankine cycle. The research methodology involves employing computational fluid dynamics (CFD) simulations alongside experimental investigations to examine the performance of an axial turbine concept under different working fluids. The results obtained indicate that R134a is the most appropriate working fluid for an axial turbine within a CTEC, outperforming ammonia, thereby implying significantly better operational efficiency.
“…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.…”
Section: Introductionmentioning
confidence: 99%
“…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.…”
The article presents the design of a four-way valve, implemented in SolidWorks software (SOLIDWORKS® i 3DEXPERIENCE® Works Simulation) and used for central heating installations in buildings. The project was carried out in order to examine the innovative design of the medium mixing mechanism and to conduct strength and FMEA analysis. The innovative solutions proposed by the authors in this work will allow valves of this type to meet stringent environmental standards. These standards are currently being introduced for this type of structural element of machine parts as part of the energy transformation of buildings. Potential failures occurring in individual elements of the four-way valve were also tested using Failure mode and effects analysis. In addition, strength tests were performed in SolidWorks software using static analysis, and optimization tests were performed on the refrigerant in terms of its impact on the environment. The characteristics of the tested materials in the valve design show that the best materials are brass and stainless steel. Brass has a Poisson’s ratio of 0.33, a tensile strength of 478.4 MPa and a yield strength of 239.7 MPa. In turn, stainless steel is characterized by the following parameters: Poisson’s ratio of 0.27, tensile strength of 685 MPa and yield strength of 292 MPa. The designed valve reduces energy consumption by 30% through a properly designed medium flow with the appropriate selection of materials. Moreover, the design reduces the thickness of the contaminant layer by 0.17 mm, with a capacity factor of −2.50% and an evaporator Δp of 3.10% (53 kPa). The performed research provides knowledge on the subject selection of appropriate material, a description of the potential failures of the structural elements of the designed four-way valve and methods of counteracting these failures. The article presents the optimization role of the tested component in the context of sustainable development.
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