Experimental and Numerical Study on Growth of Single Vapor Bubble in Upward Flow Through Vertical Mini-Tube

2011 ◽  
Author(s):  
Hiroshi Iwai ◽  
Motohiro Saito ◽  
Yuichi Kami ◽  
Yasuhiro Niina ◽  
Hideo Yoshida
Keyword(s):  
Numerical Study ◽  
Piecewise Linear ◽  
Numerical Procedure ◽  
Mass Conservation ◽  
Surface Force ◽  
Bubble Behavior ◽  
Two Phase ◽  
Intense Evaporation ◽  
Flow Through ◽  
Semi Empirical

A slug flow with phase change in a vertical mini-tube is numerically simulated on the basis of a scheme of continuum mechanics. To formulate two-phase flow, the volume of fluid, VOF, method is employed; the advection of the gas-liquid surface is expressed by the piecewise linear interface calculation, PLIC, scheme, while the effect of surface tension is evaluated by the continuum surface force, CSF, model. Since the treatment of liquid film between a bubble and tube wall is crucially important to properly predict both heat transfer and resulting fluid flow in a mini-tube, a semi-empirical approach based on subsidiary knowledge estimated from a preliminary experiment is newly proposed. Further, an additional numerical procedure is introduced to obtain allowable mass conservation even in the thin-film region with intense evaporation. Consequently, by introducing only one parameter, the physical meaning of which is clear, the bubble behavior is reasonably predicted, and its detailed mechanism is clarified.

Numerical study on two-phase flow through fractured porous media

2011 ◽  
Vol 54 (9) ◽  
pp. 2412-2420 ◽  
Author(s):  
ZhaoQin Huang ◽  
Jun Yao ◽  
YueYing Wang ◽  
Ke Tao
Keyword(s):  
Porous Media ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Fractured Porous Media ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through

Experimental Characterization of Two-Phase Flow Through Valves Applied to Liquid-Assisted Gas-Lift

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Renato P. Coutinho ◽  
Paulo J. Waltrich ◽  
Wesley C. Williams ◽  
Parviz Mehdizadeh ◽  
Stuart Scott ◽  
...  
Keyword(s):  
Water Flow ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Water Flow Rate ◽  
Phase Flow ◽  
Experimental Characterization ◽  
Two Phase ◽  
Flow Through ◽  
Gas Lift

Abstract Liquid-assisted gas-lift (LAGL) is a recently developed concept to unload wells using a gas–liquid fluid mixture. The success deployment of the LAGL technology is related to the behavior of two-phase flow through gas-lift valves. For this reason, this work presents an experimental and numerical study on two-phase flow through orifice gas-lift valves used in liquid-assisted gas-lift unloading. To the knowledge of the authors, there is no investigation in the literature on experimental characterization of two-phase flow through gas-lift valves. Experimental data are presented for methane-water flow through gas-lift valves with different orifice port sizes: 12.7 and 17.5 mm. The experiments were performed for pressures ranging from 1.00 to 9.00 MPa, gas flow rates from 0 to 4.71 m3/h, and water flow rate from 0 to 0.68 m3/min. The experimental results are compared to numerical models published in the literature for two-phase flow through restrictions and to commercial multiphase flow simulators. It is observed that some models developed for two-phase flow through restrictions could successfully characterize two-phase flow thorough gas-lift valves with errors lower than 10%. However, it is first necessary to experimentally determine the discharge coefficient (CD) for each gas-lift valve. The commercial flow simulators showed a similar performance as the models available in the literature.

Numerical Study on High Prandtl Number Liquid Bridge

2013 ◽  
Vol 712-715 ◽  
pp. 1630-1633
Author(s):  
Ru Quan Liang ◽  
Shuo Yang ◽  
Fu Sheng Yan ◽  
Jun Hong Ji ◽  
Ji Cheng He
Keyword(s):  
Gas Phase ◽  
Liquid Bridge ◽  
Surface Deformation ◽  
Numerical Study ◽  
Mass Conservation ◽  
Ambient Air ◽  
Two Phase ◽  
High Prandtl Number ◽  
Free Surface Deformation ◽  
Ambient Gas

The overall numerical analysis of liquid bridge for high Pr number fluid and flow field of ambient air under the zero-gravity environment was carried out in the present paper. The paper used level set method of mass conservation to capture two phase interfaces. Not only the free surface deformation was considered, but also the effect of ambient gas was taken into account. Simultaneously, results of stream function in liquid bridge and ambient gas-phase were given.

Modeling Bubble Behavior on a Heated Surface With Surface Pores and Sub-Surface Channels

2004 ◽  
Author(s):  
Yuming Chen ◽  
Manfred Groll ◽  
Rainer Mertz
Keyword(s):  
Heated Surface ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Bubble Behavior ◽  
Thin Film Evaporation ◽  
Enhanced Tube ◽  
Departure Size ◽  
Semi Empirical ◽  
Surface Pores ◽  
Vapor Mass

Bubble behavior and pressure fluctuation during boiling are modeled for enhanced surfaces with surface pores and sub-surface channels. The hydraulic diameter of the channels is about 0.42 mm. It is assumed that the latent heat flux is solely generated by thin-film evaporation on the channel surface. The evaporation rate is given by a semi-empirical correlation including effects of surface tension and liquid viscosity. The activation pressure and the bubble departure size are different for different pores. The vapor pressure inside the bubble is related to the channel pressure by the orifice equation. The bubble growth rate is determined by a modified Rayleigh equation. The vapor mass in a given channel volume is given by the mass conservation equation. Thus the instantaneous channel pressure and vapor volume can be determined which, in turn, govern the dynamic processes of bubble initiation and growth on various pores. This model demonstrates for the first time the dynamic picture of boiling phenomena on enhanced surfaces, e.g. the instantaneous activation, growth and detachment of bubbles on various pores, the fluctuation of channel pressure and vapor mass etc.. The model has been tested for boiling of propane and isobutane on an enhanced tube. The predictions agree reasonably well with the experiments.

Experimental and numerical study on gas-solid two-phase flow through regulating valve of pulverized coal flow

2020 ◽  
Vol 155 ◽  
pp. 1-11 ◽  
Author(s):  
Meihua Chen ◽  
Haifeng Lu ◽  
Yong Jin ◽  
Xiaolei Guo ◽  
Xin Gong ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Pulverized Coal ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Coal Flow

Pressure Surge During Cryogenic Feedline Chilldown Process

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Gagan Agrawal ◽  
S. Sunil Kumar ◽  
Deepak Kumar Agarwal
Keyword(s):  
Numerical Study ◽  
Rocket Engine ◽  
Inlet Pressure ◽  
Working Fluid ◽  
Flash Evaporation ◽  
Two Phase ◽  
Numerical Studies ◽  
Start Up ◽  
Flow Through ◽  
Pressure Surge

Cryogenic fluid entering a warm feedline absorbs heat and undergoes rapid flash evaporation leading to pressure surges, which can retard the flow inside the feedline. It may have serious repercussion in operation of the rocket engine during start up. Experimental and numerical studies are carried out to examine the effect of inlet pressure and initial feedline temperature on pressure surges. An analytical model using sinda/fluint software is developed to investigate this complex two-phase flow phenomenon including the various boiling regimes that exist during line chilling. The numerical study is carried out considering 1D flow through a cryogenic feedline of 2.47 m long and 0.01 m inner diameter with liquid nitrogen at 77.3 K as working fluid. Predictions are made for the inlet pressure in the range of 0.28–0.76 MPa and initial wall temperature of 200 K and 300 K. Subsequently, an experimental test rig is setup and the model is validated with the experimental data. The studies show that within the range of parameter considered, the magnitude of pressure surge increases exponentially with increase in inlet pressure and decreases with the prechilling of feedline.

scholarly journals Numerical Study of Two-Phase Granular Flow for Process Equipment

2000 ◽  
Vol 122 (4) ◽  
pp. 462-468 ◽  
Author(s):  
R. Djebbar ◽  
S. B. Beale ◽  
M. Sayed
Keyword(s):  
Granular Flow ◽  
Solid Phase ◽  
Numerical Study ◽  
Numerical Procedure ◽  
Process Equipment ◽  
Two Phase ◽  
Angle Of Internal Friction ◽  
Phase Liquid ◽  
Multi Phase ◽  
Realistic Geometries

This paper reports on a research program of modeling multi-phase granular flow. Both single-phase granular flow and two-phase liquid/granular flow in a pressure vessel were considered. For the latter case, detailed results based on a viscous/Mohr-Coulomb closure were compared to existing formulations. Idealized test cases indicated that the numerical procedure is sound. Subsequent simulations of two-phase flow using realistic geometries and boundary conditions showed that the pressure distribution in the solid phase is fundamentally different for the Mohr-Coulomb system than for the conventional system. The effect of the angle of internal friction, geometry, and other parameters is discussed. [S0094-9930(00)01204-X]

Numerical Simulation of Density Current Using Two Phase Flow

2006 ◽  
Author(s):  
H. Afshin ◽  
B. Firoozabadi
Keyword(s):  
Two Phase Flow ◽  
Numerical Models ◽  
Piecewise Linear ◽  
Surface Force ◽  
Density Current ◽  
Data Sets ◽  
Phase Flow ◽  
Two Phase ◽  
Continuous Surface ◽  
Current Flows

Due to shear layer at the interface of density current and ambient fluid, density current disturbs and entrains the surrounding fluid. Most existing analytical and numerical models for density current flows are based on the equations for single-phase flows. In this research, the density current has been modeled with two-phase flow model. The governing equations are continuity, x- momentum, and y- momentum equations for every fluid. The volume-of-fluid (VOF) interface tracking technique which uses a piecewise-linear interface calculation (PLIC) in each cell is used to determine the deformation of free surface in density current, numerically. Surface tension is implemented by the continuous surface stress (CSS), and continuous surface force (CSF) methods. Finally, results of these two models are compared. The model has been verified with the experimental data sets. The Results show that the model can be applied to experimental cases and has acceptable level of accuracy.

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