scholarly journals Governing equations for a seriated continuum: an unequal velocity model for two-phase flow

1975 ◽  
Author(s):  
C W Solbrig ◽  
E D Hughes
Keyword(s):  
Two Phase Flow ◽  
Velocity Model ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase

Verification of STACS-VOF Based Two-Phase Flow Model for Interfacial Flows

2012 ◽  
Vol 212-213 ◽  
pp. 1098-1102
Author(s):  
Bin Deng ◽  
Chang Bo Jiang ◽  
Zhi Xin Guan ◽  
Chao Shen
Keyword(s):  
Flow Model ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Test Cases ◽  
Phase Flow ◽  
Interfacial Flows ◽  
Governing Equations ◽  
Two Phase ◽  
Resolution Scheme ◽  
Volume Method

The numerical calculation and simulation of gas-liquid two-phase flows with interfacial deformations have nowadays become more and more popular issues in various scientific and industrial fields. In this study, a three-dimensional gas-liquid two-phase flow numerical model is presented for investigating interfacial flows. The finite volume method was used to discretize the governing equations. A High-resolution scheme of VOF method (STACS) is applied to capture the free surface. The paper outlines the methodology of STACS and its validation against three typical test cases used to verify its accuracy. The results show the STACS-VOF gives very satisfactory results for three-dimensional two-phase interfacial flows problem, and this scheme performs more accurate and less diffusive preserving interface sharpness and boundedness.

The Numerical Simulation of the Water Jet in Hydroentanglement

2011 ◽  
Vol 189-193 ◽  
pp. 2181-2184
Author(s):  
Heng Zhang ◽  
Xiao Ming Qian ◽  
Zhi Min Lu ◽  
Yuan Bai
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Multiphase Flow ◽  
Flow Model ◽  
Two Phase Flow ◽  
Water Jet ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Set Up

The functions of hydroentangled nonwovens are determined by the degree of the fiber entanglement, which depend mainly on parameters of the water jet. According to the spun lacing technology, this paper set up the numerical model based on the simplified water jetting model, establishing the governing equations, and the blended two-phase flow as the multiphase flow model. This paper simulation the water needle after the water jetting from the water needle plate in the different pressure (100bar, 60bar, 45bar, 35bar).

Nonequilibrium Modeling of Two-Phase Critical Flows in Tubes

1987 ◽  
Vol 109 (3) ◽  
pp. 731-738 ◽  
Author(s):  
F. Dobran
Keyword(s):  
Two Phase Flow ◽  
Numerical Procedure ◽  
Phase Flow ◽  
Water Mixture ◽  
Governing Equations ◽  
Two Phase ◽  
One Dimensional ◽  
Variable Diameter ◽  
Variable Step ◽  
Tube Exit

A nonequilibrium two-phase flow model is described for the analysis of critical flows in variable diameter tubes. Modeling of the two-phase flow mixture in the tube is accomplished by utilizing a one-dimensional form of conservation and balance equations of two-phase flow which account for the relative velocity and temperature differences between the phases. Closure of the governing equations was performed with the constitutive equations which account for different flow regimes, and the solution of the nonlinear set of six differential equations was accomplished by a variable step numerical procedure. Computations were carried out for a steam-water mixture with varying degrees of liquid subcooling and stagnation pressures in the vessel upstream of the tube and for different tube lengths. The numerical results are compared with the experimental data involving critical flows with variable liquid subcoolings, stagnation pressures, and tube lengths, and it is shown that the nonequilibrium model predicts well the critical flow rate, pressure distribution along the tube, and the tube exit pressure.

Water Condensation and Two-Phase Flow Modeling for a Plate Heat Exchanger Channel

2007 ◽  
Author(s):  
Charlotte Wilhelmsson ◽  
Jinliang Yuan ◽  
Bengt Sunden
Keyword(s):  
Phase Change ◽  
Two Phase Flow ◽  
Plate Heat Exchanger ◽  
Water Phase ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Plate Heat ◽  
Total Enthalpy ◽  
Vapour Condensation

There are water vapour condensation and two-phase flow in plate heat exchangers when they are used as condensers. Water phase change and flow dynamics modelling is an important but complicated task due to large change in water physical/transport properties across the water liquid-vapour interface boundary. In particular, singular-link behaviour in governing equations is present due to the large step change in the density when computational fluid dynamics (CFD) is employed. Conventional methods using ensemble averaged parameters such as void fraction are impossible to be applied to cases where high-resolution calculations and detailed analysis are required. In this study, a CFD approach is employed to model water vapour condensation and two-phase flow in a channel relevant for plate heat exchanger parallel plates. The developed model is based on the governing equations which are directly solved for the entire single- and two-phase fields. The water phase change and two-phase flow are treated by employing a water liquid-phase fraction factor based on the total enthalpy in each computational cell. The factor is defined as the ratio of the total enthalpy differential to the latent heat of condensation. The thermal-physical properties, such as density, viscosity and conductivity of the two-phase region, are calculated and updated based on the calculated value of the liquid-phase fraction factor until a converged result is reached. It is concluded that, among others, the inlet vapour velocity has significant effects on the water phase change and two-phase flow in the channel, in terms of liquid-water fraction factor distribution.

scholarly journals Numerical Simulation of Gas-Particle Two-Phase Flow in a Nozzle with DG Method

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Duan Maochang ◽  
Yu Xijun ◽  
Chen Dawei ◽  
Qing Fang ◽  
Zou Shijun
Keyword(s):  
Flow Field ◽  
Gas Phase ◽  
Mass Fraction ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Dg Method ◽  
The Impact

In this paper, the discontinuous Galerkin (DG) method is applied to solve the governing equations of the dispersed two-phase flow with the two-fluid Euler/Euler approach. The resulting governing equations are simple in form and the solution process is very natural. The characteristics of the gas-particle two-phase flow in an engine nozzle are mainly analyzed, and the impacts of the particle mass fraction and particle size on the flow field and engine performance are evaluated. Because of the addition of particles, the gas flow field undergoes significant modifications. Increase in the mass fraction leads to a significant thrust loss in the gas phase, and the impact of the particles on the gas phase could be substantial. Therefore, a quantitative study of thrust loss in the nozzle due to the particle impact is made. It is found that the gas thrust in the two-phase flow is reduced, but the total thrust of the two-phase flow increases to a certain extent.

Simplification of Ensemble Averaged Two-Phase Flow with Heat and Mass Transfer Equations for Boiling in a Channel

2008 ◽  
Vol 273-276 ◽  
pp. 616-621
Author(s):  
Hikmet Ş. Aybar ◽  
Mohsen Sharifpur
Keyword(s):  
Two Phase Flow ◽  
Fluid Model ◽  
Three Dimensional ◽  
Phase Flow ◽  
Governing Equations ◽  
Ensemble Averaging ◽  
Two Phase ◽  
Transfer Equations ◽  
Two Fluid Model ◽  
Two Fluid

Generation of vapor and predication of its behavior is an important problem in many industries. In this study, the three dimensional governing equations for turbulence two-phase flow are derived using ensemble averaging two fluid model. The governing equations are simplified by a heuristic approach based on boiling data, and the equations are used to obtain the parameters for each phase along the channel. A computer program is written for the simplified one-dimensional equations, and the results are compared with experimental data.

Experimental and numerical analysis of compressible two-phase flows in a shock tube

2015 ◽  
Vol 06 (03) ◽  
pp. 1550025 ◽  
Author(s):  
J. Bruce Ralphin Rose ◽  
S. Dhanalakshmi ◽  
G. R. Jinu
Keyword(s):  
Shock Tube ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Flow Analysis ◽  
Conservation Equation ◽  
Tube Length ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Single Temperature

The comparative study on seven equation models with two different six equations model for compressible two-phase flow analysis is proposed. The seven equations model is derived for compressible two-phase flow that is in the nonconservation form. In the present work, two different six equations model are derived for two pressures, two velocities and single temperature with the derivation of the equation of state. The closing equation for one of the six equations model is energy conservation equation while another one is closed by entropy balance equation. The partial differential form of governing equations is hyperbolic and written in the conservative form. At this point, the set of governing equations are derived based on the principle of extended thermodynamics. The method of solving single temperature from both six equation models are simple and direct solution can be obtained. Numerical simulation has been tried using one of the six equation models for air–water shock tube problems. Explicit fourth order Runge–Kutta scheme is used with Finite Volume Shock Capturing method for solving the governing equations numerically. The pressure, velocity and volume fraction variations are captured along the shock tube length through flow solver. Experimental work is carried out to magnify the initial stage of liquid injection into a gas. The outcome of six equations model for compressible two-phase flow has revealed the multi-phase flow characteristics that are similar to the actual conditions.

scholarly journals A comparison between the presence and absence of virtual viscosity in the behaviour of the two phase flow interface

2021 ◽  
pp. 163-163
Author(s):  
Iman Abbaspour ◽  
Vahid Shokri ◽  
Morteza Abbasi
Keyword(s):  
Two Phase Flow ◽  
Numerical Study ◽  
Phase Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Stability Range ◽  
Long Wavelength ◽  
First Order ◽  
Instability Range ◽  
Fortran Language

In this paper, a numerical study is performed in order to investigate the effect of the virtual viscosity on simulation of separated two-phase flow of gas-liquid. The governing equations solved by shock capturing method which can provide predicting the interface without the flow field solving. In this work, in order to calculate the numerical flux term, first-order centred scheme (Force scheme) was applied cause of its accuracy and appropriate validation. Analysis approves that the obtained stability range of this research is consistent with the classic Kelvin-Helmholtz instability equation only for the long wavelength with small amplitude. Results reveal that when the wavelengths are reduced, the specified range is not consistent and wavelength affects on instability range and it is over predicted. An algorithm for water faucet problem was developed in Fortran language. Short wavelength perturbations induce unbounded growth rates and make it impossible to achieve converging solutions. The approach taken in this article has been to adding virtual viscosity as a CFD technique, is used to remedy this deficiency.

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