scholarly journals Experimental investigation of multiphase separation in different flow regimes through T-junction with an expander section

2019 ◽  
Vol 13 (2) ◽  
pp. 5163-5181
Author(s):  
Z. Q. Memon ◽  
W. Pao ◽  
F. Hashim ◽  
S. Ahmed
Keyword(s):  
Experimental Data ◽  
Phase Separation ◽  
Slug Flow ◽  
Vertical Plane ◽  
Flow Regimes ◽  
Diameter Ratio ◽  
Superficial Velocity ◽  
Inlet Section ◽  
Water Mixture ◽  
Gas Velocity

The experimental data for phase separation of the air-water mixture in a T-Junction with the expander section after the branch arm is presented in this work. The main and run arms of the T-junction are directed along the horizontal plane with the branch arm positioned in the vertical plane. The diameter of the main arm is 74 mm, with diameter ratio(s) of, 0.67, and 0.33 in relation to branch arm. At the inlet section of the T-junction, the flow regimes generated were stratified, stratified wavy and slug flow. At the inlet, the air and water superficial velocities are in the range of 0.25 - 0.140 m/s and 0.14-0.78 m/s respectively. The effect of the expander section after the branch arm, the air superficial velocity USA and water superficial velocity USw on liquid carryover (WL3/WL1)max in branch arm have been studied. Based on the experimental data obtained for T-junction with expander section, complete phase separation of air and water was observed in stratified and stratified wavy flow for all superficial velocities and improved phase separation for slug flow. In slug flow, increasing the liquid superficial velocity improves the phase separation but increasing the gas velocity decreases the phase separation. Finally, the volume weighted phase in this new T-junction design is compared with the phase separation data of a simple T-junction.

Separation of a Two-Phase Slug Flow in Branched 90 deg Elbows

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
F. Sanchez-Silva ◽  
V. Hernandez-Perez ◽  
I. Carvajal-Mariscal ◽  
J. G. Barbosa-Saldaña ◽  
J. A. Cruz-Maya
Keyword(s):  
Experimental Data ◽  
Phase Separation ◽  
Slug Flow ◽  
Static Pressure ◽  
Radius Of Curvature ◽  
Inlet Section ◽  
Two Phase ◽  
Phase Separations ◽  
Pressure Transducers ◽  
Inclination Angles

Novel experimental data for phase separation of air-water mixtures in horizontal 90 deg branched elbows are presented in this work. The branched elbows were formed by attaching a pipe to a 90 deg elbow on the side of maximum radius of curvature, and halfway between the inlet and outlet sections of the elbow. All three arms coming from the junction were in the horizontal plane. Both the branch orientation and branch diameter were varied. Three different branch/elbow diameter ratios were tested, as well as three different branch inclination angles. In addition, the static pressure was monitored at different points along the ramified elbow using a set of pressure transducers in order to analyze and associate the pressure drop with the phase separation. At the inlet section of the elbow, the two-phase flow pattern was mainly slug flow. Based on the experimental data, a correlation for the liquid phase separation is proposed. Finally, the volume-weighted phase separation in the branched elbow was compared with the phase separations on the T-junction, and it was found that in some cases the branched elbows have a similar performance to that of the T-junctions.

Numerical evaluation of separation efficiency in converging T-junction with slug flow

2019 ◽  
Vol 30 (7) ◽  
pp. 3515-3534
Author(s):  
William Pao ◽  
Zeeshan Qadir Memon
Keyword(s):  
Phase Separation ◽  
Slug Flow ◽  
Separation Efficiency ◽  
Diameter Ratio ◽  
Flow Loop ◽  
Two Phase ◽  
Content Type ◽  
Production Platform ◽  
Major Factors ◽  
Phase Separator

Purpose Excessive liquid carryover in T-junction presents a serious operational issue in offshore production platform. Slug flow and diameter ratio of T-junction are considered as two major factors causing liquid carryover. Regular and reduced T-junction are being used as partial phase separator but their efficiency is low. Converging T-junction with two distinct diameters (primary and secondary) in branch arm is used to improve the phase separation efficiency. The motivation is to combine specific feature of regular and reduced T-junction to increase separation efficiency of existing T-junction without involving too much operational workover. The purpose of this paper is to numerically evaluate the separation efficiency of a converging T-junction design. The present model and its methodology was validated with in-house experimental data for 3 inches diameter flow loop. Design/methodology/approach The slug flow regime was simulated using incompressible Eulerian mixture model coupled with volume of fluid method to capture the dynamic gas-liquid interface. Findings The analyses concluded that T-junction with primary-secondary branch arm diameters combination of 1.0-0.5 and 0.67-0.40 managed to achieve 95 per cent separation efficiency. The research also confirmed that over reduction of T-junction secondary diameter ratio below 0.2 will lead to decrease in separation efficiency. Research limitations/implications The present research is limit to air/water two-phase flow but the general results should be applicable for wider application. Practical implications The proposed design limited excessive workover and installation for current and existing T-junction. Hence, cutting down installation cost while improving the separation efficiency. Social implications The present research resulted in higher separation efficiency, cutting down production down time and lead to operational cost saving. Originality/value The present research proposes an original and new T-junction design that can increase phase separation efficiency to over 90 per cent. The finding also confirmed that there is a limitation whereby smaller diameter ratio T-junction does not always resulted in better separation.

scholarly journals Numerical simulation of two-phase separation in T-junction with experimental validation

2018 ◽  
Vol 12 (4) ◽  
pp. 4216-4230
Author(s):  
Minh Tran ◽  
Zeeshan Memon ◽  
Ahmed Saieed ◽  
William Pao ◽  
Fakhruldin Hashim
Keyword(s):  
Phase Separation ◽  
Slug Flow ◽  
Dimensionless Parameter ◽  
Separation Efficiency ◽  
Area Under The Curve ◽  
Superficial Velocity ◽  
Separation Performance ◽  
Air Velocity ◽  
Two Phase ◽  
Average Deviation

Liquid carryover in T-junction due to splitting nature of two-phase flow causes serious issues for downstream equipment which is not designed to handle excessive liquid. In this paper, the phenomena of liquid carryover in T-junctions were analyzed using the Volume of Fraction (VOF) together with the k-ε turbulence model. T-junction separation efficiency was measured through mass flow rate fraction of air and water between the branch and main arm over a range of diameter ratios 0.6 to 1.0, water superficial velocity 0.186 to 0.558 m/s and air superficial velocity 4 to 8 m/s. The results showed simulation model was successfully validated with average deviation of less than 5% and can be used to predict phase split of slug flow in T-junction. The numerical model confirmed the significant influence of diameter ratio and superficial velocities of air and water on phase split. Reduced T-junction delivers better separation performance compared to regular T-junction. In slug flow regime, T-junction’s performance can be improved by either decreasing air velocity or increasing water velocity. A new dimensionless parameter, namely the area under the curve of separation efficiency (S), was proposed and proved as a qualified judging criteria for evaluating phase separation efficiency of T-junctions.

Kerosene-Water Flow Pattern in T-Junction Vertical Diameter Ratio 0.5 (Variation of Inclination Branch)

2014 ◽  
Vol 493 ◽  
pp. 306-312 ◽  
Author(s):  
Dewi Puspitasari ◽  
Indarto ◽  
Purnomo ◽  
Khasani
Keyword(s):  
Phase Separation ◽  
Flow Pattern ◽  
Flow Resistance ◽  
Diameter Ratio ◽  
Maximum Efficiency ◽  
Water Mixture ◽  
Inlet Flow ◽  
Junction Flow ◽  
Exploration And Production ◽  
Vertical Up

The separation is one of the important processes in exploration and production oil technology. Phase separation across T-junction with orientation vertical up branch is simplicity method to achieve maximum efficiency, but useful information is rather limited. This paper is presented only for inlet flow pattern and T-junction flow pattern of kerosene water mixture with inlet diameter 36 mm and branch diameter 19 mm (diameter ratio 0.5) on the variation inclination branch are 30o, 60oand 90o. Regulating flow by closing valve at downstream was done to obtain three flow resistance in the downstream. The flow pattern obtained in this study were : stratified (ST), three-layer-13 (3L-13) , three layer-2 (3L-2), and three layer-3 (3L-3). The results of the phase separation is best achieved under conditions inlet flow pattern stratified (ST) and T-junction three layer-3 (3L-3) flow pattern, angle 90°and downstream resistance 6471 Pa.Keywords: phase separation, T-junction, flow patterns, downstream resistance.

CFD Simulation of Hydraulics of Sieve Trays with Gas Mal-Distribution

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Mahmood Reza Rahimi ◽  
Hajir Karimi
Keyword(s):  
Experimental Data ◽  
Path Length ◽  
Gas Flow ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Flow Path ◽  
Superficial Velocity ◽  
Gas Velocity ◽  
Flow Path Length ◽  
Good Agreement

A transient three-dimensional, two-fluid computational fluid dynamics (CFD) model is developed in the Eulerian framework to predict the hydraulics of sieve trays, especially with gas maldistribution. For this purpose, an algorithm is developed to explain the hole-gas velocity and pressure drop terms along the liquid flow path length. An important modification to the previous CFD works is the use of variable, position dependent, gas superficial velocity for calculation of interphase drag term along the tray. The flow path length of tray was divided into a number of sections; gas-superficial velocity, hydraulic parameters and drag coefficient were obtained for each section. This modification has an important effect on the simulation results and causes faster convergence and better predictions of tray hydraulics. The results are in good agreement with experimental data. Model results obtained in this study have revealed that the effect of hydraulic gradient is significant for high liquid path length and may create non-uniform gas flow. This paper describes how the inlet flow maldistributions can be included in CFD simulation of sieve trays. The results of simulations with non-uniform gas velocity distributions are presented, and compared against experimental data from literature. The results are in good agreement with experimental data.

Bubble Characteristics in a Developing Vertical Gas–Liquid Upflow Using a Conductivity Probe

1999 ◽  
Vol 122 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Junping Zhang ◽  
Norman Epstein ◽  
John R. Grace ◽  
Kokseng Lim
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Flow Region ◽  
Flow Regimes ◽  
Chord Length ◽  
Bubble Velocity ◽  
Gas Velocity ◽  
Bubble Frequency ◽  
Local Bubble ◽  
Bubble Characteristics

Experiments were carried out in an 82.6-mm-dia column with a perforated distributor plate. Conductivity probes on the axis of the column were used to measure local bubble properties in the developing flow region for superficial air velocities from 0.0018 to 6.8 m/s and superficial water velocities from 0 to 0.4 m/s, corresponding to the discrete bubble, dispersed bubble, coalesced bubble, slug, churn, bridging, and annular flow regimes. Bubble frequency increased linearly with gas velocity in the discrete and dispersed bubble regimes. Bubble frequency also increased with gas velocity in the slug flow regime, but decreased in the churn and bridging regimes. Bubble chord length and its distribution were smaller and narrower in the dispersed than in the discrete bubble regime. Both the average and standard deviation of the bubble chord length increased with gas velocity in the discrete, dispersed, and churn flow regimes. However, the average bubble chord length did not change significantly in the slug flow regime due to the high population of small bubbles in the liquid plugs separating Taylor bubbles. The bubble travel length, defined as the product of local gas holdup and local bubble velocity divided by local bubble/void frequency, is used to correlate bubble characteristics and to characterize the flow regimes. [S0098-2202(00)00101-2]

Transient Multiphase Simulation in Separator Vessel Internals Design in Saudi Aramco

2016 ◽  
Author(s):  
Hussain A. Al-Khalifa ◽  
Lanre Oshinowo ◽  
Omar A. Al-Saif
Keyword(s):  
Multiphase Flow ◽  
Slug Flow ◽  
Inlet Section ◽  
Multiphase Model ◽  
Water Mixture ◽  
Gas Oil ◽  
Cfd Model ◽  
Production Forecast ◽  
Fluid Forces ◽  
Transient Multiphase Flow

The design of new multiphase separation plants or the replacement of vessels represents an opportunity to review and update the separation systems, to ensure the surface facilities lifetime with maturing production conditions. Potentially adverse operating scenarios involving slug flow could occur in the production header, leading to potentially damaging fluid forces acting on the high-pressure production trap internals. The internals design is based on the fluid forces occurring during a slug flow condition. This paper presents the application of 3-D Computational Fluid Dynamics (CFD) to simulate the realistic fluid forces acting on a novel separator inlet device, and to assess the structural integrity of the mechanical design. To generate slug conditions resulting from several adverse, but low probability, operating scenarios, OLGA, a 1-D transient multiphase flow hydraulic simulation application, was used to simulate the transient multiphase flow conditions in the production header entering the production separator using the 20-year production forecast. In a one-way coupling, the output from OLGA is used as input to the CFD model. The scenarios were carefully developed, thoroughly evaluated and agreed on by the different project stakeholders — technical services, operations and project management teams. The OLGA simulations produced the transient phase velocities and hold-ups that were applied as inlet boundary conditions to the CFD models of the separator. The transient CFD turbulent multiphase simulations used the Volume-of-Fluid model to track the gas-oil-water mixture in the inlet device and the inlet section of the separator. A discussion on the appropriate CFD multiphase model selection is presented. The hydrodynamic forces computed in the CFD model are integrated over the internal surfaces of the inlet device and mapped as a distributed pressure load for a Finite Element Analysis (FEA) structural model, to determine the mechanical reactions of the structure, a fluid-structure interaction (FSI) analysis. The methodology developed is intended for use in new internal designs for two- and three-phase separators, and slug catchers in gas/oil separation plants (GOSPs).

scholarly journals Experimental Study on the Transition Characteristics and Criterion From Wall-Peak to Core-Peak Phase Distribution in Vertical Rod Bundles

2021 ◽  
Vol 9 ◽  
Author(s):  
Quan-yao Ren ◽  
Zengping Pu ◽  
Ping Chen ◽  
Liang-ming Pan ◽  
Fawen Zhu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Distribution ◽  
Liquid Velocity ◽  
Water Mixture ◽  
Gas Velocity ◽  
Rod Bundles ◽  
Two Phase ◽  
Rod Bundle ◽  
Transition Criterion ◽  
Peak Phase

Aiming at understanding the phase distribution characteristics and developing the transition criterion from wall-peak to core-peak phase distribution in a rod bundle channel, air–water two-phase flow experiments were conducted in 5 × 5 rod bundles in the Interfacial Evolution Research Facility at Chongqing University (IERFC). Based on the experimental data, the influences of gas velocity, liquid velocity, mixing vane spacer grid (MVSG), and geometrical size on phase distribution have been analyzed in detail. With the increasing superficial gas velocity and decreasing liquid velocity, the wall-peak phase distribution turned to core-peak. The wall-peak phase distribution was enhanced by an MVSG, and the transition from the transitional phase distribution to the wall-peak phase distribution appeared when the air–water mixture flowed through the MVSG. The gap size was the key factor for the transition of phase distribution in rod bundles. Moreover, the transition criterion from wall-peak to core-peak phase distribution was developed based on present experimental data and the data in the literature, which was also verified based on the limited data. More experiments were recommended to focus on the detailed phase distribution in the rod bundle channel with different geometrical sizes.

scholarly journals Review of Factors Affecting the Phase-Redistribution in the Branching T-Junction

2021 ◽  
Vol 84 (1) ◽  
pp. 60-77
Author(s):  
Faheem Ejaz ◽  
William Pao ◽  
Mohammad Shakir Nasif
Keyword(s):  
Phase Separation ◽  
Flow Regimes ◽  
Chemical Processes ◽  
Separation Process ◽  
Superficial Velocity ◽  
Geometrical Parameters ◽  
Two Phase ◽  
Factors Affecting ◽  
Velocity Flow

Whenever T-junctions are used in chemical processes and petroleum industries for two-phase separation, a maldistribution of phases is observed between outlets of the junction. Currently, the regular T-junctions are utilized in the industry due to which equipment downstream faces high liquid carryovers. Unfortunately, downstream equipment is not capable of handling high liquid carryovers and they trip frequently, consequently. This review manuscript summarizes the effect of different factors that influence phase separation in the T-junction. This article refers to the geometrical parameters, phase superficial velocity flow regimes encounter during the separation process, and different side arm modifications. This article is a contribution to this field as it summarizes and concludes all these factors comprehensively, to give a verdict on ways to improve phase separation. It is also recommended that the effect of side arm modifications or combinations must be explored for further understanding.

Initiation and Statistical Evolution of Horizontal Slug Flow With a Two-Fluid Model

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
A. O. Nieckele ◽  
J. N. E. Carneiro ◽  
R. C. Chucuya ◽  
J. H. P. Azevedo
Keyword(s):  
Experimental Data ◽  
Slug Flow ◽  
Fluid Model ◽  
Subsequent Development ◽  
Complex Flow ◽  
Horizontal Pipes ◽  
Dimensional Version ◽  
Two Fluid Model ◽  
Log Normal ◽  
Two Fluid

In the present work, the onset and subsequent development of slug flow in horizontal pipes is investigated by solving the transient one-dimensional version of the two-fluid model in a high resolution mesh using a finite volume technique. The methodology (named slug-capturing) was proposed before in the literature and the present work represents a confirmation of its applicability in predicting this very complex flow regime. Further, different configurations are analyzed here and comparisons are performed against different sets of experimental data. Predictions for mean slug variables were in good agreement with experimental data. Additionally, focus is given to the statistical properties of slug flows such as shapes of probability density functions of slug lengths (which were represented by gamma and log-normal distributions) as well as the evolution of the first statistical moments, which were shown to be well reproduced by the methodology.

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