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.

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.

Evaluation of Void Fraction Correlations for the Statistical and Numerical Analysis of Two-Phase Flows Inside Producing Geothermal Wells

2008 ◽  
Author(s):  
A. A´lvarez del Castillo ◽  
E. Santoyo ◽  
O. Garci´a-Valladares ◽  
P. Sa´nchez-Upton
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Temperature Gradients ◽  
Production Performance ◽  
Phase Flow ◽  
Two Phase ◽  
Precise Knowledge ◽  
Geothermal Wells ◽  
Gas Void Fraction

The modeling of heat and fluid flow inside two-phase geothermal wells is a vital task required for the study of the production performance. Gas void fraction is one of the crucial parameters required for a better prediction of pressure and temperature gradients in two-phase geothermal wells. This parameter affects the correct matching between simulated and measured data. Modeling of two-phase flow inside wells is complex because two phases exist concurrently (exhibiting various flow patterns that depend on their relative concentrations, the pipe geometry, and the mass flowrate). A reliable modeling requires the precise knowledge of the two-phase flow patterns (including their transitions and some flow parameters). In this work, ten empirical correlations were used to estimate the gas void fraction in vertical-inclined pipes, and to evaluate their effect on the prediction of two-phase flow characteristics of some Mexican geothermal wells. High quality downhole pressure/ temperature logs collected from four producing geothermal wells were studied [Los Azufres, Mich. (Az-18); Los Humeros, Pue. (H-1), and Cerro Prieto, B.C. (M-90 and M-201)]. The pressure/ temperature gradients were simulated using an improved version of the wellbore simulator GEOPOZO, and the gas void fraction correlations. The simulated results were statistically compared with measured field data.

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

Effects of Channel Length on Gas-Liquid Two-Phase Flow Phenomena in a Microchannel

2011 ◽  
Author(s):  
Hideo Ide ◽  
Ryuji Kimura ◽  
Masahiro Kawaji
Keyword(s):  
Void Fraction ◽  
Flow Rate ◽  
Liquid Flow ◽  
Mass Velocity ◽  
Two Phase Flow ◽  
Liquid Flow Rate ◽  
Optical Measurement ◽  
Phase Flow ◽  
Two Phase ◽  
The Mean

An optical measurement system was used to investigate the effect of microchannel length on the characteristics of adiabatic gas-liquid two-phase flow. Experiments were conducted with a 1,676 mm long, circular microchannel with an inner diameter of 100 μm. Two-phase flow patterns, void fraction and velocities of gas plug/slug and liquid slugs were measured at different locations between the gas-liquid mixer and channel exit. The experimental values of the mean void fraction and the mean velocity of liquid slug agreed well with the homogeneous flow model predictions when the liquid flow rate was constant and the mass velocity of the gas was low. The flow pattern transition from slug flow to ring film flow was observed when the mass velocity of the gas was increased while the liquid flow rate was kept constant.

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