Computational Study of Turbulent Gas-Particle Flow in a Venturi

1986 ◽  
Vol 108 (2) ◽  
pp. 248-253 ◽  
Author(s):  
Myung Kyoon Chung ◽  
Hyung Jin Sung ◽  
Kye Bock Lee
Keyword(s):  
Computational Study ◽  
Fluid Model ◽  
Particle Flow ◽  
Dilute Gas ◽  
Averaged Equations ◽  
Air Stream ◽  
Bulk Motion ◽  
Loading Ratio ◽  
Two Fluid Model ◽  
Mixing Length Theory

A “two-fluid” model has been applied to predict turbulent dilute gas-particle flow through a Venturi tube. Bulk motion of particles is considered as a secondary fluid flow which exchanges mass and momentum with the primary conveying air stream. Closure of the time-averaged equations is achieved by modelling turbulent second-order correlations with an extended mixing-length theory. Proposed closure model is found to aptly simulate the dependency of the static pressure drop on the particle size, flow rate and the loading ratio.

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.

Effect of Particulate Diffusion on the Free Turbulent Flow Based on Two-Fluid

2005 ◽  
Author(s):  
R. Fesanghari ◽  
H. Basirat Tabrizi ◽  
F. Hamdullahpur
Keyword(s):  
Solid Phase ◽  
Fluid Model ◽  
Mixing Layer ◽  
Stochastic Approach ◽  
Finite Volume Scheme ◽  
Loading Ratio ◽  
Turbulent Plane ◽  
Two Fluid Model ◽  
Free Turbulent Flow ◽  
Two Fluid

This paper is concerned with the two-dimensional gas-solid turbulent plane-mixing layer. The solid phase is considered a continuum and a two-fluid model, which is coupled by source terms due to particle drag and diffusion. Finite volume scheme has been employed for the governing equations. The simulation results show that the ratio of particle diffusion coefficient and kinematics viscosity of the carrier gas, have significant influence on the prediction of particles trend. In addition, it is observed that the loading ratio has no significant effect on the gas-solid flow prediction. The results are compared with the existed experimental data’s of others. This kind of modeling will ease the time consuming, stochastic approach of the Eulearian-Lagrangian methods but needs further investigation on the particle diffusivity term.

Application of Lumley’s Drag Reduction Model to Two-Phase Gas-Particle Flow in a Pipe

1991 ◽  
Vol 113 (1) ◽  
pp. 130-136 ◽  
Author(s):  
Kee Soo Han ◽  
Myung Kyoon Chung ◽  
Hyung Jin Sung
Keyword(s):  
Drag Reduction ◽  
Fluid Model ◽  
Average Particle Size ◽  
Viscous Sublayer ◽  
Particle Flow ◽  
Average Particle ◽  
Two Phase ◽  
Reduction Model ◽  
Sublayer Thickness ◽  
Two Fluid Model

A “two-fluid model” has been incorporated with Lumley’s drag reduction model to analyze the mechanism of momentum transfer in the turbulent dilute gas-particle flow in a vertical pipe. The change of the effective viscous sublayer thickness by the presence of particles is modeled by Lumley’s theoretical model. The numerical computations of the friction factor and the pressure drop in a fully developed pipe flow are in good agreement with the corresponding experimental data for an average particle size of 15 μm. It is proved that Lumley’s model is successful in predicting the correct reduction behavior of the drag in the gas-particle flows. It has been confirmed that the effective viscous sublayer thickness for two-phase gas-particle flow is dependent on the particle relaxation time, Kolmogoroff time scale and the solids-gas loading ratio.

The RANS, PDF and TBL Simulations of Turbulent Gas-Solid Particle Flow in Vertical Pipe

2006 ◽  
Author(s):  
Alexander I. Kartushinsky ◽  
Efstathios E. Michaelides ◽  
Leonid I. Zaichik
Keyword(s):  
Solid Particle ◽  
Solid Phase ◽  
Fluid Model ◽  
Coupling Model ◽  
Particle Flow ◽  
Particle Collision ◽  
Two Phase ◽  
Turbulence Modulation ◽  
Carrier Fluid ◽  
Two Fluid Model

The numerical simulation of turbulent gas-solid particle flow in vertical round pipe is performed & analyzed by three different approaches: RANS 2D modeling, PDF approach (Zaichik’s model 2001) & by two-phase TBL (turbulent boundary layer approach). The given performances include all relevant force factors imposed on the motion of solid phase (two-fluid model is considered): particle-turbulence, particle-particle, particle-wall interactions, two-lift the Magnus & Saffman forces and buoyancy (gravitational) force. The dispersed phase is considered as a polydispersed phase composed of finite number of particle fractions and the mass & momentum equations are closed with the help of implementation of original “collision” model (Kartushinsky & Michaelides, 2004). The two/four-way coupling model of Gillandt & Crowe (1998) is accounted for turbulence modulation. The numerical results show that retaining of second diffusion terms in both directions (in streamwise & transverse directions) aligns the average x-velocity components of gas and dispersed phases as well as the particle mass concentration and k-profiles across the flow in case of both PDF and RANS 2D approaches that versus the distributions of parameters obtained by two-phase TBL approach. This is reasonable due to additional effect of fluxes diffusion of the carrier fluid & solid phase in the main direction derived from turbulence fluctuation and inter-particle collision which smoothes the profile shapes.

A Numerical Method for Gas-Particle Flows With Accumulation

2006 ◽  
Author(s):  
Xiang Zhao ◽  
Sijun Zhang
Keyword(s):  
Mathematical Model ◽  
Numerical Modelling ◽  
Numerical Method ◽  
Fluid Model ◽  
Particle Flow ◽  
Flow Conditions ◽  
Accumulation Zone ◽  
Particle Flows ◽  
Two Fluid Model ◽  
Two Fluid

A mathematical model is proposed to describe the gas-particle flow in a bed packed with particles. The model is in essence the same as the two fluid model developed on the basis of the space-averaged theorem but extended to consider the interactions among the gas, powder and packed particles and the static and dynamic holdups of powder. In particular, a method is proposed to determine the boundary between powder mobile and non-mobile zones, i.e. the profile of powder accumulation zone. The validity of the numerical modelling is examined by comparing the predicted and measured distributions of powder accumulation under various flow conditions.

scholarly journals Computational Study of Gas-Solid Flow in a Horizontal Stepped Pipeline

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Zhengquan Li ◽  
Kaiwei Chu ◽  
Renhu Pan ◽  
Aibing Yu ◽  
Jiaqi Yang
Keyword(s):  
Pressure Drop ◽  
Pipe Wall ◽  
Computational Study ◽  
Solid Wall ◽  
Fluid Model ◽  
Gas Velocity ◽  
Interaction Forces ◽  
Solid Flow ◽  
Two Fluid Model ◽  
Wall Interaction

In this paper, the mechanism governing the particle-fluid flow characters in the stepped pipeline is studied by the combined discrete element method (DEM) and computational fluid dynamics (CFD) model (CFD-DEM) and the two fluid model (TFM). The mechanisms governing the gas-solid flow in the horizontal stepped pipeline are investigated in terms of solid and gas velocity distributions, pressure drop, process performance, the gas-solid interaction forces, solid-solid interaction forces, and the solid-wall interaction forces. The two models successfully capture the key flow features in the stepped pipeline, such as the decrease of gas velocity, solid velocity, and pressure drop, during and after the passage of gas-solid flow through the stepped section. What is more important, the reason of the appearance of large size solid dune and pressure surge phenomena suffered in the stepped pipeline is investigated macroscopically and microscopically. The section in which the blockage problem most likely occurs in the stepped pipeline is confirmed. The pipe wall wearing problem, which is one of the most common and critical problems in pneumatic conveying system, is analysed and investigated in terms of interaction forces. It is shown that the most serious pipe wall wearing problem happened in the section which is just behind the stepped part.

Implementation of Two-Fluid Model for Dilute Gas-Solid Flow in Pipes With Rough Walls

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Ashraf Uz Zaman ◽  
Donald John Bergstrom
Keyword(s):  
Surface Roughness ◽  
Gas Phase ◽  
Numerical Study ◽  
Fluid Model ◽  
Vertical Tube ◽  
Particle Flow ◽  
Layer Model ◽  
Two Layer Model ◽  
Two Fluid Model ◽  
Two Fluid

A numerical study was carried out to investigate the performance of a two-layer model for predicting turbulent gas-particle flows in rough pipes. An Eulerian–Eulerian two-fluid formulation was used to model both the gas and solid phases for turbulent gas-particle flow in a vertical tube. The stresses developed in the particle phase were calculated using the kinetic theory of granular flows while the gas-phase stresses were described using an eddy viscosity model. The two-fluid model typically uses a two-equation k-ɛ model to describe the gas phase turbulence, which includes the suppression and enhancement effects due to the presence of particles. For comparison, a two-layer model was also implemented since it has the capability to include surface roughness. The current study examines the predictions of the two-layer model for both clear gas and gas-solid flows in comparison to the results of a conventional low Reynolds number model. The paper specifically documents the effects of surface roughness on the turbulence kinetic energy and granular temperature for gas-particle flow in both smooth and rough pipes.

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