CFD simulation of interfacial instability from the nozzle in the formation of viscous core-annular flow

2016 ◽  
Vol 94 (10) ◽  
pp. 2004-2012 ◽  
Author(s):  
Manuel J. Macías-Hernández ◽  
Omar Dávila-Maldonado ◽  
Ariel Guzmán-Vargas ◽  
Rogelio Sotelo-Boyás ◽  
Liliana Zarazua-Villalobos
Keyword(s):  
Annular Flow ◽  
Cfd Simulation ◽  
Interfacial Instability ◽  
Viscous Core

CFD Simulation of Two-Phase Vertical Annular Flow in Both Upward and Downward Direction in a Small Pipe

2019 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
John Shirokoff ◽  
Mohammad Azizur Rahman
Keyword(s):  
Film Thickness ◽  
Multiphase Flow ◽  
Pressure Gradient ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Flow Direction ◽  
Flow Behavior ◽  
Two Phase ◽  
Downward Flow ◽  
Disturbance Wave

Abstract Computational fluid dynamics (CFD) simulation is presented to investigate the annular flow behavior in the vertical pipe by using ANSYS Fluent platform 17.2. The study was analyzed complex behavior of annular flow in two cases (upward and downward flow) for different air superficial velocities and range of Reynolds number for water, in order to obtain the effect of orientation flow and increasing superficial gas and liquid velocities on the base film, mean disturbance wave thickness, the average longitudinal size of disturbance wave as well as pressure gradient. For multiphase flow model, the volume of fluid method (VOF) for two-phase flow modelling was used and coupled with RNG k-ε turbulence model to predict fully annular flow structures in the upward and downward flow direction. From CFD simulation results, it is clear to see how increases in air velocity result in reductions in film thickness and increase in pressure gradient. Additionally, the results showed monotonic enhancement of film thickness occurring in tandem with increases in the liquid flow rate. However, due to the effect of gravitational force and interfacial friction, the film thickness and pressure gradient are slightly larger for the upward flow than for the downward flow. The results agree with the recent experimental data that studied the annular flow behavior and pressure drop in the upward and downward flow direction. This study will be very helpful in understanding multiphase flow behavior in natural gas wells.

CFD simulation of core annular flow through sudden contraction and expansion

2012 ◽  
Vol 86-87 ◽  
pp. 153-164 ◽  
Author(s):  
V.V.R. Kaushik ◽  
Sumana Ghosh ◽  
Gargi Das ◽  
Prasanta Kumar Das
Keyword(s):  
Annular Flow ◽  
Cfd Simulation ◽  
Sudden Contraction ◽  
Flow Through ◽  
Contraction And Expansion

scholarly journals Simulation of Drag Reducer Polymer (DRP) for Single and Annular Two Phase Flow in Horizontal Pipe

2018 ◽  
Vol 13 (2) ◽  
pp. 154-164
Author(s):  
Cindy Dianita ◽  
Asep Handaya Saputra ◽  
Puteri Amelia Khairunissa
Keyword(s):  
Drag Reduction ◽  
Annular Flow ◽  
Single Phase ◽  
Cfd Simulation ◽  
Fluid Velocity ◽  
Flow Equation ◽  
Equation Model ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase

Drag reducing polymers (DRP) is one of drag reducer types that is widely used in industry as an additive to improve fluid flow efficiency in pipes. This study is conducted to analyze the parameters that influence the efficiency of DRP through developing equation model, and to see the phenomenon of drag reduction that occurs in fluid flow through computational fluid dynamic (CFD) simulation. The data used are obtained from experiments by Vancko (1997) for a single phase flow of water. As for two-phase annular flow, four experiments data are used namely by Vancko (1997), Al-Sarkhi and Hanratty (2001a,b) and Fernandes et al. (2004). Parameters such as fluid velocity and pipe diameter are analyzed based on the model equations proposed in this study. The final single phase flow equation model as the output of this study gives a value for onset drag reduction i.e 4.00 with an error up to 18%. While the proposed annular flow equation with and without drag reduction effect is only suitable when the condition of fluid film distribution is uniform and symmetrical with the error around 20%, i.e. for smaller diameter pipes. The CFD simulation results shows a change in the fluid velocity profile; becoming more parabolic, indicating an increase in the mean fluid velocity up to 0.43%, as the effect of DRP.

Control of Interfacial Instability in Core-Annular Flow

2018 ◽  
Author(s):  
Nadia Mehidi Bouam ◽  
Houria Djessas ◽  
Amar Djema ◽  
Ilhem Benaissa
Keyword(s):  
Annular Flow ◽  
Interfacial Instability

Three Dimensional CFD Simulation of Condensation Inside Inclined Tubes

2017 ◽  
Author(s):  
Amirhosein Moonesi Shabestary ◽  
Eckhard Krepper ◽  
Dirk Lucas ◽  
Thomas Höhne
Keyword(s):  
Heat Transfer ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Cooling System ◽  
Heat Removal ◽  
Normal Operation ◽  
Cooling Systems ◽  
Horizontal Pipes ◽  
Subcooled Water ◽  
Operation Conditions

The current paper comprises CFD-modelling and simulation of condensation and heat transfer inside horizontal pipes. Designs of future nuclear boiling water reactor concepts are equipped with emergency cooling systems which are passive systems for heat removal. The emergency cooling system consists of slightly inclined horizontal pipes which are immersed in a tank of subcooled water. At normal operation conditions, the pipes are filled with water and no heat transfer to the secondary side of the condenser occurs. In the case of an accident the water level in the core is decreasing, steam comes in the emergency pipes and due to the subcooled water around the pipe, this steam will condense. The emergency condenser acts as a strong heat sink which is responsible for a quick depressurization of the reactor core when any accident happens. The actual project is defined in order to model all these processes which happen in the emergency cooling systems. The most focus of the project is on detection of different morphologies such as annular flow, stratified flow, slug flow and plug flow. The first step is the investigation of condensation inside a horizontal tube by considering the direct contact condensation (DCC). Therefore, at the inlet of the pipe an annular flow is assumed. In this step, the Algebraic Interfacial Area Density (AIAD) model is used in order to simulate the interface. The second step is the extension of the model to consider wall condensation effect as well which is closer to the reality. In this step, the inlet is pure steam and due to the wall condensation, a liquid film occurs near the wall which leads to annular flow. The last step will be modelling of different morphologies which are occurring inside the tube during the condensation via using the Generalized Two-Phase Flow (GENTOP) model extended by heat and mass transfer. By using GENTOP the dispersed phase is able to be considered and simulated. Finally, the results of the simulations will be validated by experimental data which will be available in HZDR. In this paper the results of the first part has been presented.

scholarly journals MODELLING AIR AND WATER TWO-PHASE ANNULAR FLOW IN A SMALL HORIZONTAL PIPE

2016 ◽  
Vol 42 ◽  
pp. 1660158 ◽  
Author(s):  
JUN YAO ◽  
YUFENG YAO ◽  
ANTONINO ARINI ◽  
STUART MCIIWAIN ◽  
TIMOTHY GORDON
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Liquid Film ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Two Phase Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe

Numerical simulation using computational fluid dynamics (CFD) has been carried out to study air and water two-phase flow in a small horizontal pipe of an inner diameter of 8.8mm, in order to investigate unsteady flow pattern transition behaviours and underlying physical mechanisms. The surface liquid film thickness distributions, determined by either wavy or full annular flow regime, are shown in reasonable good agreement with available experimental data. It was demonstrated that CFD simulation was able to predict wavy flow structures accurately using two-phase flow sub-models embedded in ANSYS-Fluent solver of Eulerian–Eulerian framework, together with a user defined function subroutine ANWAVER-UDF. The flow transient behaviours from bubbly to annular flow patterns and the liquid film distributions revealed the presence of gas/liquid interferences between air and water film interface. An increase of upper wall liquid film thickness along the pipe was observed for both wavy annular and full annular scenarios. It was found that the liquid wavy front can be further broken down to form the water moisture with liquid droplets penetrating upwards. There are discrepancies between CFD predictions and experimental data on the liquid film thickness determined at the bottom and the upper wall surfaces, and the obtained modelling information can be used to assist further 3D user defined function subroutine development, especially when CFD simulation becomes much more expense to model full 3D two-phase flow transient performance from a wavy annular to a fully developed annular type.

CFD simulation on oil-water annular flow through CAF generator device

2019 ◽  
Vol 42 (15) ◽  
pp. 1861-1873 ◽  
Author(s):  
Wenming Jiang ◽  
Junqiang Wu ◽  
Shilin Du ◽  
Chengsong Liu ◽  
Yang Liu
Keyword(s):  
Annular Flow ◽  
Cfd Simulation ◽  
Flow Through ◽  
Oil Water

CFD SIMULATION OF TWO PHASE ANNULAR FLOW IN NATURAL GAS PIPELINES

2019 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
John Shirokoff ◽  
Mohammad Azizur Rahman
Keyword(s):  
Natural Gas ◽  
Annular Flow ◽  
Cfd Simulation ◽  
Gas Pipelines ◽  
Two Phase ◽  
Natural Gas Pipelines
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