scholarly journals Algorithms for determination of the vector velocity field in a two-phase gas-liquid flow

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3569-3576
Author(s):  
Grzegorz Ligus ◽  
Maciej Masiukiewicz ◽  
Stanisław Anweiler ◽  
Marek Wasilewski
Keyword(s):  
Energy Efficiency ◽  
Velocity Field ◽  
Liquid Flow ◽  
Particle Image ◽  
Two Phase Flow ◽  
Qualitative Assessment ◽  
Phase Flow ◽  
Two Phase ◽  
Gas Liquid Flow

Energy efficiency is a key issue of sustainable development. During the design of industrial devices, it strives to achieve the highest possible energy efficiency. In the industrial systems, two-phase flow is a difficult task, especially the prediction, and maintenance of the two-phase flow regime. That is why this research proposes the evaluation and choice of an algorithm that will give a hint of the device design for which the hydrodynamic conditions of the two-phase mixture flow may be evalu-ated. The tests were carried out in a rectangular vertical narrow channel, as this type of device is in common use. The work aimed to show which algorithm is better for such evaluation. Parameters such as pressure drop, heat, mass, and momentum transfer are influenced by the phase velocity field. Still, various models are used for the determination of the velocity field. Therefore, there is a problem of choosing a model that will give the results closest to the real conditions. Flow visualization gives the non-invasive determination of the actual velocity field. An analysis of the velocity field was performed, which showed that for different two-phase flow regimes there are differences for given algorithms. The following algorithms were used to determine the velocity vector field: adaptive correlation method and adaptive particle image velocity method were used which are the parts of the general digital particle image velocimetry. The determination of the velocity fields in the quantitative and qualitative assessment of a given two-phase flow re-gime was obtained. The result of the research is the evaluation of algorithms for characterization two-phase gas-liquid flow.

Behavior of the Two-Phase Gas-Liquid Flow at the Inlet of a Catalytic Reactor

2019 ◽  
Vol 19 (2) ◽  
pp. 123-131
Author(s):  
O. P. Klenov ◽  
A. S. Noskov
Keyword(s):  
Liquid Phase ◽  
Uniform Distribution ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Catalytic Reactor ◽  
Two Phase ◽  
Gas Consumption ◽  
Flow Diagrams ◽  
Gas Liquid Flow

The work was aimed at studying the behavior of the two-phase gas-liquid flow at the inlet pipe of a catalytic reactor. Apart from the classical approach using literature flow diagrams, methods of computational hydrodynamics were used for 3D simulation of the space propagation of phases in the pipeline. The results obtained demonstrated non-uniform distribution of the liquid phase through the outlet section of the pipeline and the time-unsteady mass consumption of the liquid phase. The maximal peak consumptions were ca. 3 times as high as the average values. With the data on the flow diagrams, the CFD simulation demonstrated that variations in the gas consumption within the range under study do not cause changes in the behavior of the two-phase flow but an increase in the gas consumption results in smoothening of the non-uniform distribution of the liquid phase at the outlet pipe. The data on the flow behavior are necessary for designing catalytic reactors to provide uniform propagation of the two-phase flow over the catalyst bed, for example, hydrotreatment reactors used in refineries.

Numerical Simulation of the Gas-Liquid Flow in a Rotary Gas Separator

1998 ◽  
Vol 120 (1) ◽  
pp. 41-48 ◽  
Author(s):  
G. Lackner ◽  
F. J. S. Alhanati ◽  
S. A. Shirazi ◽  
D. R. Doty ◽  
Z. Schmidt
Keyword(s):  
Void Fraction ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Numerical Procedure ◽  
Phase Flow ◽  
Two Phase ◽  
Free Gas ◽  
Gas Separator ◽  
Gas Liquid Flow ◽  
Gas Void Fraction

The presence of free gas at the pump intake adversely affects the performance of an electrical submersible pump (ESP) system, often resulting in low efficiency and causing operational problems. One method of reducing the amount of free gas that the pump has to process is to install a rotary gas separator. The gas-liquid flow associated with the down hole installation of a rotary separator has been investigated to address its overall phase segregation performance. A mathematical model was developed to investigate factors contributing to gas-liquid separation and to determine the efficiency of the separator. The drift-flux approach was used to formulate this complex two-phase flow problem. The turbulent diffusivity was modeled by a two-layer mixing-length model and the relative velocity between phases was formulated based on published correlations for flows with similar characteristics. The well-known numerical procedure of Patankar-Spalding for single-phase flow computations was extended to this two-phase flow situation. Special discretization techniques were developed to obtain consistent results. Special under relaxation procedures were also developed to keep the gas void fraction in the interval [0, 1]. Predicted mixture velocity vectors and gas void fraction distribution for the two-phase flow inside the centrifuge are presented. The model’s predictions are compared to data gathered on a field scale experimental facility to support its invaluable capabilities as a design tool for ESP installations.

scholarly journals Some problems of hydrodynamics of two-phase flow mixtures in minichannels

2014 ◽  
Vol 35 (2) ◽  
pp. 93-101
Author(s):  
Monika Wengel ◽  
Barbara Miłaszewicz ◽  
Roman Ulbrich
Keyword(s):  
Two Phase Flow ◽  
Early Stage ◽  
Phase Flow ◽  
Test Results ◽  
Two Phase ◽  
Key Issues ◽  
Gas Liquid Flow ◽  
Regime Map ◽  
Flow Regime Map

Abstract Gas-liquid two-phase flow in minichannels has been the subject of increased research interest in the past few years. Evaluation, however, of today’s state of the art regarding hydrodynamics of flow in minichannels shows significant differences between existing test results. In the literature there is no clear information regarding: defining the boundary between minichannels and conventional channels, labelling of flow patterns. The review of literature on the hydrodynamics of gas-liquid flow in minichannels shows that, despite the fact that many research works have been published, the problem of determining the effect of diameter of the minichannel on the hydrodynamics of the flow is still at an early stage. Therefore, the paperpresents the results of research concerning determination of flow regime map for the vertical upward flow in minichannels. The research is based on a comprehensive analysis of the literature data and on the research that has been carried out. Such approach to the mentioned above problems concerning key issues of the two-phase flow in minichannels allowed to determine ranges of occurrence of flow structures with a relatively high accuracy.

Flow Pattern Transition in Pipes Using Data-Driven and Physics-Informed Machine Learning

2020 ◽  
Author(s):  
André M. Quintino ◽  
Davi L. L. N. da Rocha ◽  
Roberto Fonseca Jr. ◽  
Oscar M. H. Rodriguez
Keyword(s):  
Machine Learning ◽  
Experimental Data ◽  
Flow Pattern ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Data Driven ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Pattern Transition ◽  
Gas Liquid Flow

Abstract Flow pattern is an important engineering design factor in two-phase flow in the chemical, nuclear and energy industries, given its effects on pressure drop, holdup, and heat and mass transfer. The prediction of two-phase flow patterns through phenomenological models is widely used in both industry and academy. In contrast, as more experimental data become available for gas-liquid flow in pipes, the use of data-driven models to predict flow-pattern transition, such as machine learning, has become more reliable. This type of heuristic modeling has a high demand for experimental data, which may not be available in some industrial applications. As a consequence, it may fail to deliver a sufficiently generalized transition prediction. Incorporation of physics in machine learning is being proposed as an alternative to improve prediction and also to reduce the demand for experimental data. This paper evaluates the use of hybrid-physics-data machine learning to predict gas-liquid flow-pattern transition in pipes. Random forest and artificial neural network are the chosen tools. A database of experiments available in the open literature was collected and is shared in this work. The performance of the proposed hybrid model is compared with phenomenological and data-driven machine learning models through confusion matrices and graphics. The results show improvement in prediction performance even with a low amount of data for training. The study also suggests that graphical comparison of flow-pttern transition boundaries provides better understanding of the performance of the models than the traditional metric

Gas-Liquid Flow Through Horizontal Eccentric Annuli: CFD and Experiments Compared

2011 ◽  
Author(s):  
Mehmet Sorgun ◽  
Reza E. Osgouei ◽  
M. Evren Ozbayoglu ◽  
A. Murat Ozbayoglu
Keyword(s):  
Liquid Flow ◽  
High Speed ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Flow Patterns ◽  
Phase Flow ◽  
Cfd Model ◽  
Flow Loop ◽  
Two Phase ◽  
Gas Liquid Flow

Although flow of two-phase fluids is studied in detailed for pipes, there exists a lack of information about aerated fluid flow behavior inside a wellbore. This study aims to simulate gas-liquid flow inside horizontal eccentric annulus using an Eulerian-Eulerian computational fluid dynamics (CFD) model for two-phase flow patterns i.e., dispersed bubble, dispersed annular, plug, slug, churn, wavy annular. To perform experiments using air-water mixtures for various in-situ air and water flow rates, a flow loop was constructed. A digital high speed camera is used for recording each test dynamically for identification of the liquid holdup and flow patterns. Results showed that CFD model predicts frictional pressure losses with an error less than 20% for all two-phase flow patterns when compared with experimental data.

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