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.

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.

Study of the 90° Elbows Performance as Phase Separators in an Air-Water Two-Phase Flow

2003 ◽  
Author(s):  
Valente Herna´ndez P. ◽  
Florencio Sa´nchez S. ◽  
Miguel Toledo V. ◽  
Georgiy Polupan
Keyword(s):  
Phase Separation ◽  
Slug Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Pressure Gradients ◽  
Two Phase ◽  
Branch Diameter ◽  
Independent Variables ◽  
Inclination Angles ◽  
Phase Separator

In order to observe the 90° elbows performance as phase separators in an air-water two-phase flow, experimental results for the phase split which occurs at a 90° branched elbow are presented. The branched elbow geometry was varied in order to have three (branch diameter / elbow diameter) ratios and three branch inclination angles. Also the pressure was monitored at different points of the elbow with ramification in order to examine the pressure drop effect. The flow pattern upstream was mainly slug flow. First, the analysis of the main independent variables effect, (superficial velocities, branch inclination angle, ratio of diameters and pressure gradients) was carried out, then a correlation for the phase split was developed and, finally a comparison was made with data of phase separation in T junctions obtained by Azzopardi [1] and Soliman [2], as a result, a better behavior as phase separator was found for the elbow.

Experimental Determination of Hydrodynamic Parameters of Air-Water Two-Phase Slug Flow in Horizontal Pipes

2012 ◽  
Author(s):  
Carlos H. Romero ◽  
María A. Márquez ◽  
Sissi D. Vergara ◽  
María T. Valecillos
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Electronic Device ◽  
Water System ◽  
Superficial Velocity ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Type Pattern ◽  
Elongated Bubble

Two phase slug flow is the most common flow pattern for horizontal and near-horizontal pipelines. This study is designed to determine experimental velocities of elongated bubbles, lengths of liquid slugs and elongated bubbles, and slug frequencies for twenty flow rates combinations of a two phase air-water system that belong to a slug type pattern in horizontal pipes with a non invasive electronic device made of Photo-diodes (emitter) and photo-transistors (receiver) in a non visible length wave of 940 nanometers. The non intrusive electronic device is validated by simultaneously taking pictures with a high speed camera, (Kodak model Ektapro 4540 mx Imager, at shooting speed of 4500 frames per second, the picture resolution is 256 × 256 pixels), through a visualization cell filled with glycerin. This work is done with acrylic pipes of 0,03175 m inner diameter, to ensure complete flow development, the pictures are taken from a visualization cell located at a x/D = 249, the electronic device is located at x/D = 250. Air superficial velocity ranged between 0.156 and 0.468 m/s while water superficial velocity ranged between 0.159 and 1.264m/s. It is found that the non intrusive electronic device formed by photo diodes and photo transistors is an accurate technique that can be used in the determination of elongated bubble velocities, lengths and slug frequencies.

Numerical Simulation of Double Inlet Cylinder Cyclone Using CFD

2013 ◽  
Vol 275-277 ◽  
pp. 558-561
Author(s):  
Xiao Ming Yuan ◽  
Hui Jun Zhao ◽  
Jing Yi Qu
Keyword(s):  
Flow Field ◽  
Volume Fraction ◽  
Separation Efficiency ◽  
Separation Performance ◽  
Two Phase ◽  
Phase Volume Fraction ◽  
Fluid Field ◽  
Cylindrical Cyclone ◽  
Discrete Phase ◽  
New Type

Designed a new type of double inlet cylindrical cyclone. For search the separation performance in a cylindrical cyclone. By use of CFD，applied the RSM turbulence model and Euler two-phase flow method and ASM which to simulate separation process and flow field within a double inlet cylindrical cyclone. Then compared with the single inlet cyclone，obtained velocity distribution. Analyzed the differences of discrete phase volume fraction between different viscosity. The results show that the new-style cyclone caught more stable fluid field and higher separation efficiency. And when the viscosity is about 0.75 kg/m•s， the separation efficiency and stability of the oil core is higher. Preliminary flow field law is shown up.

Transition of Bubbly to Slug Flow in a Short Vertical Channel of Gas-Liquid Two-Phase Flow

2014 ◽  
Vol 881-883 ◽  
pp. 721-725
Author(s):  
Mohd Zamri Zainon ◽  
Mohd Ardan Zubir ◽  
Rahizar Ramli
Keyword(s):  
Slug Flow ◽  
Two Phase Flow ◽  
Vertical Channel ◽  
Superficial Velocity ◽  
Phase Flow ◽  
Flow Loop ◽  
Two Phase ◽  
Slip Ratio ◽  
Wide Range ◽  
Simple Flow

Transitions of bubbly to slug flow have been investigated for wide range of flow conditions via visualization technique. The effects of velocities of both phases were examined with variety of combinations and the experimentations were focused on the air-water flow with an industrial scale two-phase flow loop. The results show that the formations of slugs were easy with the increasing gas superficial velocity during a fixed liquid superficial velocity and were difficult when velocity of the liquid phase increases. These transitions were then evaluated using the ratio of velocities of both phases or called the slip ratio and from there a simple flow pattern map was constructed.

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.

scholarly journals Integrated Clarification and Purification of Monoclonal Antibodies by Membrane Based Separation of Aqueous Two-Phase Systems

Antibodies ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 40 ◽  
Author(s):  
Thomas Kruse ◽  
Axel Schmidt ◽  
Markus Kampmann ◽  
Jochen Strube
Keyword(s):  
Monoclonal Antibodies ◽  
Phase Separation ◽  
Chinese Hamster ◽  
Contact Angles ◽  
Cell Protein ◽  
Phase System ◽  
Separation Performance ◽  
Downstream Process ◽  
Two Phase ◽  
Cultivation Broth

Therapeutic monoclonal antibodies (mAb) are used for the treatment of numerous serious diseases, which have led to an increasing demand over the last decades. Increased cell density and mAb titer of the cultivation broth lead to great challenges for the subsequent clarification and capture operations in the downstream process. As an alternative approach to the conventional downstream process, a selective mAb extraction via an aqueous two-phase system (ATPS) directly from the cultivation broth of a mAb producing industrial relevant chinese hamster ovary (CHO) cell line was investigated. An efficient purification of the mAb was accomplished by the ATPS composition. The phase separation was realized by a newly developed membrane based phase separator. Moreover, a complete cell removal was integrated into this process by the used membrane. A selectivity between both phases was achieved by membrane modification. Yields up to 93% in the light phase and removal of process related impurities were obtained after aqueous two-phase extraction (ATPE). Phase separation performance as well as contact angles on the membrane were characterized for different ATPS. ATPE directly from the cultivation broth in combination with the new membrane based phase separation led to a mAb yield of 78% with a simultaneous reduction of deoxyribonucleic acid (DNA) and host cell protein (HCP) load.

Effect of Tube Size on Flow Pattern of Air-Water Two-Phase Flow in Horizontal Tubes

2013 ◽  
Vol 746 ◽  
pp. 575-580
Author(s):  
Xue Min Liu ◽  
Zhou Hang Li ◽  
Yu Xin Wu ◽  
Jun Fu Lu
Keyword(s):  
Flow Pattern ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Plug Flow ◽  
Tube Diameter ◽  
Superficial Velocity ◽  
Phase Flow ◽  
Transition Line ◽  
Two Phase

Aiming at the diameter range of boiler water wall tubes in practical engineering application, the air-water two phase flow pattern in horizontal tube was experimentally investigated in tubes with different inner diameters of 20mm and 8 mm under atmosphere condition. The stratified flow, wave flow, plug flow, slug flow, annular flow, bubbly flow and mist flow were observed in the tubes. Most of the experimental points agree well with the Baker flow pattern map when they appear in the map. With the experimental results, the range lines between the flow patterns were suggested for the tube of 20mm in inner diameter as well as 8mm. As the water superficial velocity increases, the annular flow transforms into mist flow at a decreasing air superficial velocity. The two phase flow patterns transition line is similar in tendency for different tubes. The slug flow transforms into annular flow at an increasing air superficial velocity as tube diameter decreases. The stratified flow transforms into slug flow at an increasing water superficial velocity as tube diameter decreases. The transition line between plug flow and slug flow is independent of tube diameter.

Phase Separation in Vertical Header of Microchannel Condensers—A Mechanistic Model

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jun Li ◽  
Pega Hrnjak
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Separation Efficiency ◽  
Mechanistic Model ◽  
Force Balance ◽  
Vapor Compression ◽  
Liquid Separation ◽  
Two Phase ◽  
Energy Conversion Systems ◽  
Balance Analysis

Abstract Phase separation has been proven to increase performance of condensers of energy conversion systems (in vapor compression systems). Instead of conventional design, the inlet to a microchannel condenser prototype is in the middle of the height. After the first pass, in the vertical second header of the condenser, vapor phase separates from liquid phase due to gravity, and sometimes other effects. In ideal case vapor should go to the top and liquid to the bottom, resulting in increased heat transfer. Due to interaction between vapor and liquid, separation is not perfect, expressed through the separation efficiency. A mechanistic model presented in the paper is built to predict the phase separation efficiency based on force balance analysis for the liquid phase and correlations for the two-phase pressure drop. For the force balance criteria, liquid phase is divided into droplets and film and treated separately. Initial agreement with experiment is achieved to be within ±15%. For a second header at one inlet condition of the flow, the liquid separation efficiency is a function of the vapor separation efficiency. Liquid separation efficiency decreases with increasing inlet mass flux.

Two-Phase Slug Flow in a Narrow Rectangular Channel Under Inclined Conditions

2014 ◽  
Author(s):  
Yang Wang ◽  
Changqi Yan ◽  
Licheng Sun ◽  
Chaoxing Yan ◽  
Yanmin Zhou ◽  
...  
Keyword(s):  
Slug Flow ◽  
High Speed ◽  
Rectangular Channel ◽  
Video Camera ◽  
Superficial Velocity ◽  
Bubble Velocity ◽  
Two Phase ◽  
Camera System ◽  
Taylor Bubble ◽  
Inclination Angles

The characteristics of two-phase slug flow in a narrow rectangular channel with cross section of 3.25 mm × 43 mm under vertical and inclined conditions are investigated using a high speed video camera system. It is found that the velocity of Taylor bubble in vertical continuous slug flow could be well predicted by the Nicklin et al. (1962) correlation, in which C0 is given by the correlation of Ishii (1977), and the drift velocity given by the correlation of Sadatomi et al. (1982) or Clanet et al. (2004). For low two-phase superficial velocity (FrTP ≤ 3.5), the Taylor bubble velocities gradually increase with the increasing in inclination angles and almost approximate the maximum value for θ = 30°. For high two-phase superficial velocity (FrTP > 3.5), the influence of the inclination angles on the Taylor bubble velocity is insignificant, and the bubble velocity under vertical condition is slight lower than those under inclined conditions. For the inclined cases, the nose of Taylor bubble is deviated from the centerline and its position is the function of the two-phase superficial velocity as well as the inclination angle.

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