Two-Fluid Model Simulation of Thermophoretic Deposition for Fine Particles in a Turbulent Boundary Layer

2007 ◽  
Author(s):  
Sh. Shahriari ◽  
H. Basirat Tabrizi
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Gas Phase ◽  
Fine Particles ◽  
Model Simulation ◽  
Fluid Model ◽  
Governing Equations ◽  
Diffusion Term ◽  
Two Fluid Model ◽  
Two Fluid

In this present paper, thermophoretic depositions of fine particles are used in a heated turbulent boundary layer over very small plate via two-fluid model, or Eulerian-Eulerian approach. The Prandtl’s mixing length model of turbulence is used for the closure problem. The governing equations of gas phase are coupled with the governing equations of particle phase in two-way model, while uses the particle diffusion term as another coupling term. The equations are solved numerically by using finite difference method. One can obtain the convergence by numerical calculations much easier than with no diffusion term. A vast amount of information can be extracted for this kind of modeling. The effect of important parameters such as diffusion factor, gravity and thermophoretic force are considered. The cooler temperature of plate results higher particles deposition or concentration on the flat plate. Also, the larger particle size diameters delay the maximum particles deposition further distance away from the plate front edge. The results give the correct physical prediction overall.

scholarly journals Mathematical study on two-fluid model for flow of K–L fluid in a stenosed artery with porous wall

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
R. Ponalagusamy ◽  
Ramakrishna Manchi
Keyword(s):  
Theoretical Study ◽  
Fluid Model ◽  
Porous Wall ◽  
Governing Equations ◽  
Rate Of Increase ◽  
Special Cases ◽  
Stenosed Artery ◽  
Flow Through ◽  
Two Fluid Model ◽  
Two Fluid

AbstractThe present communication presents a theoretical study of blood flow through a stenotic artery with a porous wall comprising Brinkman and Darcy layers. The governing equations describing the flow subjected to the boundary conditions have been solved analytically under the low Reynolds number and mild stenosis assumptions. Some special cases of the problem are also presented mathematically. The significant effects of the rheology of blood and porous wall of the artery on physiological flow quantities have been investigated. The results reveal that the wall shear stress at the stenotic throat increases dramatically for the thinner porous wall (i.e. smaller values of the Brinkman and Darcy regions) and the rate of increase is found to be 18.46% while it decreases for the thicker porous wall (i.e. higher values of the Brinkman and Darcy regions) and the rate of decrease is found to be 10.21%. Further, the streamline pattern in the stenotic region has been plotted and discussed.

Cavitating Flow Simulation in a Closed Pump Sump by Two-Fluid Model and Its PIV Verification

2003 ◽  
Author(s):  
Yu Xu ◽  
Yulin Wu ◽  
Shuhong Liu ◽  
Yong Li
Keyword(s):  
Fluid Model ◽  
Flow Simulation ◽  
Cavitating Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Averaged Equations ◽  
Flow Through ◽  
Pump Sump ◽  
Two Fluid Model ◽  
Two Fluid

In this paper, the two-fluid model was adopted to analyze the cavitating flow. Based on Boltzmann equation, governing equations for two-phase cavitating flow were obtained by using the microscopic kinetic theory, in which the equation terms for mass and momentum transportations can be obtained directly. Then the RNG k–ε–kg turbulence model, that is RNG k–ε model for the liquid phase and kg model for the cavity phase, was used to close the Reynolds time-averaged equations. According to the governing equations above, the simulation of the two-phase cavitating flow through a closed pump sump has been carried out. The calculated results have been compared with a PIV experiment. Good agreement exhibited.

scholarly journals On the quest for a hyperbolic effective-field model of disperse flows

2013 ◽  
Vol 731 ◽  
pp. 184-194 ◽  
Author(s):  
Daniel Lhuillier ◽  
Chih-Hao Chang ◽  
Theo G. Theofanous
Keyword(s):  
Fluid Mechanics ◽  
Field Model ◽  
Fluid Model ◽  
Effective Field ◽  
Engineering Practice ◽  
Governing Equations ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Interpenetrating Continua ◽  
Final Closure

AbstractThe cornerstone of multiphase flow applications in engineering practice is a scientific construct that translates the basic laws of fluid mechanics into a set of governing equations for effective interpenetrating continua, the effective-field (or two-fluid) model. Over more than half a century of development this model has taken many forms but all of them fail in a way that was known from the very beginning: mathematical ill-posedness. The aim of this paper is to refocus awareness of this problem from a unified fundamental perspective that clarifies the manner in which such failures took place and to suggest the means for a final closure.

A Concise Numerical Model of Gas-Liquid Stratified Wavy Flow

2012 ◽  
Vol 198-199 ◽  
pp. 103-107
Author(s):  
Guo Zhen Li ◽  
Ya Lei Yuan
Keyword(s):  
Gas Phase ◽  
Fluid Model ◽  
Equation Model ◽  
Wall Function ◽  
Liquid Holdup ◽  
One Dimensional ◽  
Drop Velocity ◽  
Flow Parameters ◽  
Two Fluid Model ◽  
Two Fluid

On the basis of the conservation law of the flow field and the two-fluid model, a one-dimensional steady state hydraulics model of the gas-liquid stratified wavy flow is established. The method accounts for the effects of the turbulence through the use of the standard K-ε two-equation model of turbulence with the wall function method employed near the wall. The gas phase and the liquid phase in the wavy region are considered respectively as two points for simplification. The model permits the prediction of flow parameters such as liquid holdup,pressure drop, velocity profile and so on. It is easy to calculate and the result is compared with the experiments and other models and agrees well with them.

Modeling Interfacial Interactions and Turbulence in the Near-Wall Region of a Vertical Bubbly Boundary Layer

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Jamel Chahed ◽  
Lucien Masbernat
Keyword(s):  
Boundary Layer ◽  
Void Fraction ◽  
Fluid Model ◽  
Second Order ◽  
Turbulence Closure ◽  
Wall Region ◽  
Turbulence Structure ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Near Wall

Abstract A two-fluid model with second-order turbulence closure is used for the simulation of a turbulent bubbly boundary layer. The turbulence model is based on the decomposition of the Reynolds stress tensor in the liquid phase into two parts: a turbulent part and a pseudo-turbulent part. The reduction in second-order turbulence closure in the near-wall region is interpreted according to a modified wall logarithmic law. Numerical simulations of bubbly boundary layer developing on a vertical flat plate were performed in order to analyze the bubbles effect on the liquid turbulence structure and to evaluate the respective roles of turbulence and of interfacial forces in the near-wall distribution of the void fraction. The two-fluid model with the second-order turbulence closure succeeds in reproducing the diminution of the turbulent intensity observed in the near-wall region of bubbly boundary layer and the increase in turbulence outside the boundary layer. The analysis of the interfacial force in the near-wall zone has led to the development of relatively simple formulation of the lift-wall force in the logarithmic zone that depends on dimensionless distances to the wall. After appropriate adjustment, this formulation makes it possible to reproduce the shape of the near-wall void fraction peaking observed in bubbly boundary layer experiments.

A two-fluid model simulation of an industrial moving grate waste incinerator

2020 ◽  
Vol 104 ◽  
pp. 183-191 ◽  
Author(s):  
Zihong Xia ◽  
Peng Shan ◽  
Caixia Chen ◽  
Hailiang Du ◽  
Jie Huang ◽  
...  
Keyword(s):  
Model Simulation ◽  
Fluid Model ◽  
Waste Incinerator ◽  
Two Fluid Model ◽  
Two Fluid
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