scholarly journals Numerical simulation of laminar core-annular flow in a 90°bend

2015 ◽  
Author(s):  
S. M. Park ◽  
G. Ooms ◽  
M. J. B. M. Pourquie
Keyword(s):  
Numerical Simulation ◽  
Annular Flow

Numerical Simulation of Oil-Water Core Annular Flow in a U-Bend Based on the Eulerian Model

2014 ◽  
Vol 37 (4) ◽  
pp. 659-666 ◽  
Author(s):  
Fan Jiang ◽  
Yijun Wang ◽  
Jiajie Ou ◽  
Conggui Chen
Keyword(s):  
Numerical Simulation ◽  
Annular Flow ◽  
Eulerian Model ◽  
Oil Water

Direct numerical simulation of a turbulent core-annular flow with water-lubricated high viscosity oil in a vertical pipe

2018 ◽  
Vol 849 ◽  
pp. 419-447 ◽  
Author(s):  
Kiyoung Kim ◽  
Haecheon Choi
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Pipe Flow ◽  
Annular Flow ◽  
Volume Fraction ◽  
Phase Interface ◽  
High Viscosity ◽  
Vertical Pipe ◽  
The Core ◽  
High Viscosity Oil

The characteristics of a turbulent core-annular flow with water-lubricated high viscosity oil in a vertical pipe are investigated using direct numerical simulation, in conjunction with a level-set method to track the phase interface between oil and water. At a given mean wall friction ($Re_{\unicode[STIX]{x1D70F}}=u_{\unicode[STIX]{x1D70F}}R/\unicode[STIX]{x1D708}_{w}=720$, where $u_{\unicode[STIX]{x1D70F}}$ is the friction velocity, $R$ is the pipe radius and $\unicode[STIX]{x1D708}_{w}$ is the kinematic viscosity of water), the total volume flow rate of a core-annular flow is similar to that of a turbulent single-phase pipe flow of water, indicating that water lubrication is an effective tool to transport high viscosity oil in a pipe. The high viscosity oil flow in the core region is almost a plug flow due to its high viscosity, and the water flow in the annular region is turbulent except for the case of large oil volume fraction (e.g. 0.91 in the present study). With decreasing oil volume fraction, the mean velocity profile in the annulus becomes more like that of turbulent pipe flow, but the streamwise evolution of vortical structures is obstructed by the phase interface wave. In a reference frame moving with the core velocity, water is observed to be trapped inside the wave valley in the annulus, and only a small amount of water runs through the wave crest. The phase interface of the core-annular flow consists of different streamwise and azimuthal wavenumber components for different oil holdups. The azimuthal wavenumber spectra of the phase interface amplitude have largest power at the smallest wavenumber whose corresponding wavelength is the pipe circumference, while the streamwise wavenumber having the largest power decreases with decreasing oil volume fraction. The overall convection velocity of the phase interface is slightly lower than the core velocity. Finally, we suggest a predictive oil holdup model by defining the displacement thickness in the annulus and considering the boundary layer characteristics of water flow. This model predicts the variation of the oil holdup with the superficial velocity ratio very well.

NUMERICAL SIMULATION ON VERTICAL UPWARD GAS-LIQUID ANNULAR FLOW BASED ON THE S-CLSVOF METHOD

2017 ◽  
Author(s):  
Yajun Deng ◽  
Bo Yu ◽  
Dongliang Sun ◽  
Yongtu Liang
Keyword(s):  
Numerical Simulation ◽  
Annular Flow

Three-dimensional numerical simulation of saturated annular flow boiling in a narrow rectangular microchannel

2020 ◽  
Vol 149 ◽  
pp. 119246 ◽  
Author(s):  
Yang Luo ◽  
Wei Li ◽  
Kan Zhou ◽  
Kuang Sheng ◽  
Shuai Shao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Annular Flow ◽  
Flow Boiling ◽  
Three Dimensional ◽  
Rectangular Microchannel

scholarly journals Numerical simulation of annular flow boiling in microchannels

2016 ◽  
Vol 8 (1) ◽  
pp. 61-82 ◽  
Author(s):  
Z Guo ◽  
BS Haynes ◽  
DF Fletcher
Keyword(s):  
Numerical Simulation ◽  
Annular Flow ◽  
Flow Boiling

Research on Coanda Effect Appeared in Oil-Air Annular Flow through the Conical Diffuser

2014 ◽  
Vol 668-669 ◽  
pp. 331-335
Author(s):  
Qi Guo Sun ◽  
Ying Wang ◽  
Xiong Shi Wang
Keyword(s):  
Numerical Simulation ◽  
Liquid Phase ◽  
Pressure Drop ◽  
Annular Flow ◽  
Radial Pressure ◽  
Coanda Effect ◽  
Expansion Angle ◽  
Flow Through ◽  
Radial Pressure Gradient ◽  
Coandǎ Effect

Physical model and numerical simulation model for oil-air annular flow through conical diffusers are built by Fluent, and Coanda Effect, a commonly phenomenon, appeared in this kind of oil-air annular flow field is studied, especially influences of Coanda Effect on the attachment of the liquid phase of annular flow trended to the curved wall are analyzed in detail by changing expansion angles to calculate the radial pressure distribution and pressure drop, employed numerical simulation method, in this paper. The simulation results show that the expansion angle has a great influence on the attachment of liquid phase in annular flow to the curved wall, the radial pressure gradient is an important factor of the Coanda Effect which make the liquid phase of annular flow convey near the wall, and the radial pressure gradient will decrease but the pressure drop increase when the expansion angle becomes larger. These conclusions will provide useful reference in designing pipelines conveying the two-phase annular flow in oil-air lubrication system.

scholarly journals Experiment and Numerical Simulation on Gas-Liquid Annular Flow through a Cone Sensor

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2923 ◽  
Author(s):  
Denghui He ◽  
Senlin Chen ◽  
Bofeng Bai
Keyword(s):  
Numerical Simulation ◽  
Annular Flow ◽  
Gas Flow ◽  
Low Pressure ◽  
Pressure Recovery ◽  
Liquid Distribution ◽  
Wet Gas ◽  
Sensor Structure ◽  
Gas Measurement ◽  
Flow Through

The cone meter has been paid increasing attention in wet gas measurement, due to its distinct advantages. However, the cone sensor, which is an essential primary element of the cone meter, plays a role in the measurement of wet gas flow that is important, but not fully understood. In this article, we investigate the gas-liquid annular flow through a cone sensor by experiment and numerical simulation. Emphasis is put on the influences of pressure recovery characteristics and flow structure, and how they are affected by the cone sensor. The results show that the vortex length is shortened in gas-liquid annular flow, compared with that in single-phase gas flow. The pressure recovery length is closely related with the vortex length, and shorter vortex length leads to shorter pressure recovery length. The gas-liquid distribution suggests that flow around the apex of back-cone is very stable, little liquid is entrained into the vortex, and no liquid appears around the low pressure tapping, which makes a more stable pressure at the apex of cone sensor feasible. This finding highlights the importance of obtaining the low pressure from the back-cone apex, which should be recommended in the multiphase flow measurement. Our results may help to guide the optimization of the cone sensor structure in the wet gas measurement.

scholarly journals Numerical Simulation on Forced Convective Condensation of Steam Upward Flow in a Vertical Pipe

2014 ◽  
Vol 6 ◽  
pp. 589250 ◽  
Author(s):  
Guo-Dong Qiu ◽  
Wei-Hua Cai ◽  
Shu-Lei Li ◽  
Zhi-Yong Wu ◽  
Yi-Qiang Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Velocity Field ◽  
Slug Flow ◽  
Annular Flow ◽  
Upward Flow ◽  
Vertical Pipe ◽  
Simulation Results ◽  
Churn Flow ◽  
Good Agreement

A transient three-dimensional volume of fluid (VOF) simulation on condensation of upward flow of wet steam inside a 12 mm i.d. vertical pipe is presented. The effect of gravity and surface tension are taken into account. A uniform wall temperature has been fixed as boundary conditions. The mass flux is 130~6400 kg m−2's−1 and the turbulence inside the vapor phase and liquid phase have been handled by Reynolds stress model (RSM). The vapor quality of fluid is 0~0.4. The numerical simulation results show that, in all the simulation conditions, the bubbly flow, slug flow, churn flow, wispy annular flow, and annular flow are observed; in addition, the results of flow pattern are in good agreement with the regime map from Hewitt and Roberts. The typical velocity field characteristic of each flow pattern and the effect of velocity field on heat transfer of condensation are analyzed, indicating that the slug flow and churn flow have obvious local eddy. However, no obvious eddy is observed in other flow patterns and the streamlines are almost parallel to the flow direction. The simulation results of heat transfer coefficients and frictional pressure drop show good agreement with the correlations from existing literatures.

scholarly journals Numerical simulation of heavy oil flows in pipes using the core-annular flow technique

2009 ◽  
Author(s):  
K. C. O. Crivelaro ◽  
Y. T. Damacena ◽  
T. H. F. Andrade ◽  
A. G. B. Lima ◽  
S. R. Farias Neto
Keyword(s):  
Numerical Simulation ◽  
Heavy Oil ◽  
Annular Flow ◽  
The Core
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