Mathematical Modelling of Gas Flow with Heavy Solid Particles Based on Eulerian Approach

2019 ◽  
Vol 40 (11) ◽  
pp. 1944-1949
Author(s):  
D. A. Gubaidullin ◽  
B. A. Snigerev
Keyword(s):  
Mathematical Modelling ◽  
Gas Flow ◽  
Solid Particles ◽  
Eulerian Approach

LES of Particle-Laden Flow With Inter-Particle Collisions

2003 ◽  
Author(s):  
Mikhael Gorokhovski ◽  
Anna Chtab
Keyword(s):  
Gas Flow ◽  
Particle Interaction ◽  
Solid Particles ◽  
Particle Interactions ◽  
Particle Collisions ◽  
Cpu Time ◽  
Eddy Simulation ◽  
Preferential Concentration ◽  
Large Eddy ◽  
Particle Laden Flow

By analogy with kinetic approach, the gas-solid turbulent flow was considered as an ensemble of interacting both stochastic liquid and solid particles. In this way, the motion equation for the solid particle along a smoothed trajectory has been derived. To close this equation, the statistical temperature of particles has been introduced and expressed by statistical properties of turbulence. The smoothed particles dynamics was then computed along with large-eddy simulation (LES) of turbulent channel gas flow with “two-way” coupling of momentum. The calculated results are compared with the experiment of Kulick et. al. (1994) and with computation of Yamomoto et. al. (2001), where the inter-particle interaction has been simulated by hard-sphere collisions with prescribed efficiency. It has been shown that our computation with smoothed motion of particle is relatively in agreement with experiment and computations of Yamomoto et. al. (2001). At the same time, the model presented in the paper has a following advantage: it, practically, does not require an additional CPU time to account for inter-particle interactions. The turbulence attenuation by particles and the preferential concentration of particles in the low-turbulence region have been shown.

Laser Measurements of Fly Ash Rebound Parameters for Use in Trajectory Calculations

1987 ◽  
Vol 109 (4) ◽  
pp. 535-540 ◽  
Author(s):  
W. Tabakoff ◽  
M. F. Malak
Keyword(s):  
Gas Flow ◽  
Initial Conditions ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Solid Particles ◽  
Dust Particles ◽  
Laser Doppler Velocimeter ◽  
Laser Measurements ◽  
Flow Through ◽  
Small Dust

This paper describes an experimental method used to find particle restitution coefficients. The equations that govern the motion of solid particles suspended by a compressible gas flow through a turbomachine depend on the restitution coefficients. Analysis of the data obtained by a laser-Doppler velocimeter (LDV) system of the collision phenomenon gives the restitution ratios as a function of the incidence angle. From these ratios, the particle velocity components after collision are computed and used as the initial conditions to the solution of the governing equations of motion for particle trajectories. The erosion of metals impacted by small dust particles can be calculated by knowing the restitution coefficients. The alloy used in this investigation was 410 stainless steel.

Modeling of Particle-Laden Cold Flow in a Cyclone Gasifier

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Pantea Hadi Jafari ◽  
Dzmitry Misiulia ◽  
J. Gunnar I. Hellström ◽  
B. Rikard Gebart
Keyword(s):  
Gas Flow ◽  
Numerical Approach ◽  
Solid Particles ◽  
Bottom Plate ◽  
Single Particles ◽  
Cold Flow ◽  
Lagrangian Simulation ◽  
Swirl Intensity ◽  
The Impact ◽  
Simulation Time

Isothermal transient Eulerian–Lagrangian simulation of the turbulent gas–solid flow in a cyclone gasifier with two inlet tubes at 890 °C has been performed. The single-phase gas flow is modeled using SSG Reynolds stress turbulence model. Ten thousand representative solid particles of different sizes are injected from each inlet continuously at every second of simulation time. Particles are finally stopped as soon as they arrive at the outlet or reach the bottom plate of the gasifier. The effect of particle-to-gas coupling on the pressure and velocity of the flow and particles motion inside the gasifier is studied. The numerical approach can reasonably predict the impact of particle load on the gas flow as presented in the experimental results. Single particles are traveled throughout the transient gas flow field by using Lagrangian approach. High temperature of the gas flow inside the gasifier has significant effects on the swirl intensity reduction, damping the turbulence in the core region, pressure, and particle behaviors. However, the presence of solid particles does not have a notable influence on the swirl intensity and turbulence.

Characterization of Yttrium-Doped Barium Zirconate Nanocrystalline Powder Prepared by Spray Pyrolysis

2014 ◽  
Vol 798-799 ◽  
pp. 407-412 ◽  
Author(s):  
Eliana Navarro Santos Muccillo ◽  
M.D. Gonçalves ◽  
Robson L. Grosso ◽  
R. Muccillo
Keyword(s):  
Particle Size ◽  
Spray Pyrolysis ◽  
Gas Flow ◽  
Proton Conductor ◽  
Ceramic Materials ◽  
Solid Particles ◽  
Nanocrystalline Powders ◽  
Nanocrystalline Powder ◽  
Barium Zirconate ◽  
Medium Particle

Investigation on polycrystalline electroceramics involves the synthesis, the consolidation and the analysis of the electrical behavior, along with careful evaluation of the final microstructure. The synthesis of ceramic powders with controlled characteristics is crucial in the study of materials with optimized properties. Distinct properties may be found in ceramic materials prepared by the several existing methods, due to chemical and phase homogeneities, and to the particle size distribution or medium particle size. In this work, yttrium-doped barium zirconate proton conductor was synthesized by spray pyrolysis, and characterized by several techniques aiming identifying the influence of some parameters of this method of synthesis with particle characteristics. Nanocrystalline powders synthesized at 600-700oC were found to be cubic and single phase. Moreover, depending on the gas flow and furnace temperature, spheroid and porous or cubic and solid particles may be obtained.

Study on the Configuration Effect of a Vortex Finder for a Gas-Solid Cyclone Separator Using Eulerian-Eulerian Approach

2013 ◽  
Author(s):  
Moonho Choi ◽  
Sungwon Lee ◽  
Jin-Ki Ham
Keyword(s):  
Pressure Loss ◽  
Erosion Rate ◽  
Separation Efficiency ◽  
Solid Particles ◽  
Least Square ◽  
Design Parameters ◽  
Reduced Pressure ◽  
Eulerian Approach ◽  
Method Of Least Square ◽  
Vortex Finder

Granular model, a part of Eulerian-Eulerian approach is implemented to improve a gas-solid cyclone separator’s performances which are largely determined by dimensions of a vortex finder. Design-Of-Experiments method analyzes the performances such as pressure loss, separation efficiency, and erosion rate of each variation model due to the change of design parameters of the vortex finder. Separation efficiencies due to the motion of solid particles are predicted according to the classical efficiency model by using the method of least square. The numerical results are validated by comparing with previously reported experimental data. The standard Stairmand design cyclone is improved judging from the reduced pressure loss by 43%, the reduced cut size by 63% and the reduced erosion rate by 2% by changing the position and the diameter of the vortex finder.

Predictable Model for Characteristics of One-Dimensional Solid-Gas-Liquid Three-Phase Mixtures Flow Along a Vertical Pipeline With an Abrupt Enlargement in Diameter

1999 ◽  
Vol 121 (2) ◽  
pp. 330-342 ◽  
Author(s):  
Natsuo Hatta ◽  
Masaaki Omodaka ◽  
Fumitaka Nakajima ◽  
Takahiro Takatsu ◽  
Hitoshi Fujimoto ◽  
...  
Keyword(s):  
Gas Flow ◽  
Sudden Change ◽  
Flow Characteristics ◽  
Point Of View ◽  
Solid Particles ◽  
Governing Equations ◽  
One Dimensional ◽  
Three Phase ◽  
Experimental Values ◽  
The One

This paper treats the numerical analysis of the rising process of a solid-gas-liquid three-phase mixture along a vertical pipeline with an abrupt enlargement in diameter. The system of governing equations used is based upon the one-dimensional multifluid model and the transitions of gas flow pattern are taken into account in the system of governing equations. For the case of a sudden enlargement in diameter in a coaxial pipeline, the procedure of the numerical calculation to obtain the flow characteristics in the pipeline section after a sudden change in diameter has been established here. Furthermore, in order to confirm the validity of the present theoretical model by the comparison between the calculated and experimental values, the experiments have been made using four kinds of lifting pipes, including the straight one. Thereby, it has been found that the numerical model proposed here gives good fit to the prediction of the flow rates of lifted water and solid particles against that of air supplied for the case of a sudden change in diameter. In addition, the flowing process for each phase has been investigated from a photographic point of view. As a result, we found that the moving process of the solid particles depends strongly upon the volumetric flux of gas-phase as well as the submergence ratio.

EQUILIBRIUM VELOCITY DISTRIBUTION FUNCTIONS FOR A KINETIC MODEL OF TWO-PHASE FLOWS

1995 ◽  
Vol 05 (02) ◽  
pp. 191-211 ◽  
Author(s):  
LIONEL SAINSAULIEU
Keyword(s):  
Velocity Distribution ◽  
Gas Flow ◽  
Stokes Equations ◽  
Volume Fraction ◽  
Velocity Distribution Function ◽  
Distribution Functions ◽  
Solid Particles ◽  
Navier Stokes ◽  
Two Phase ◽  
Entropy Balance

We consider a cloud of solid particles in a gas flow. The cloud is described by a probability density function which satisfies a kinetic equation. The gas flow is modeled by Navier-Stokes equations. The two phases exchange momentum and energy. We obtain the entropy balance of the gas flow and deduce some bounds for the volume fraction of the gas phase. Writing the entropy balance for the dispersed phase enables one to determine the particles equilibrium velocity distribution function when the gas flow is known.

Study of Particle Ingestion Through Two-Stage Gas Turbine

2014 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Leading Edge ◽  
Suction Side ◽  
Solid Particles ◽  
Two Stage ◽  
Trailing Edge ◽  
Erosion Rates ◽  
Tracking Model ◽  
Over The Top

This paper presents a numerical study of particle laden gas flow through a two-stage hp axial turbine, by means of an in-house code based on the Lagrangian tracking model and the finite element method. As fly-ash solid particles trajectories and locations of impacts are predicted, the local erosion rates and the deteriorations of blades are assessed. The computed trajectories provide a detailed description of particles behaviors and reveal that particle impacts on the aft of vane pressure side usually lead to significant variations in the directions of particles to the next rotor blade, and subsequently particles impact the suction side. The plots of equivalent erosion rates indicate the vanes and blades locations which suffer more erosion. The first vane pressure surface is impacted more than any other component, but higher rates are seen at the top corner from trailing edge. The critical regions of erosion wear in the first rotor are observed over the top of blade leading edge extending along the tip as well as a rounding of the top corner from trailing edge. In the second vane, the regions of higher erosion are revealed over the last third of leading edge and the top corner extending along tip. The erosion in the second rotor is over a large area of suction side till the tip corner. The predicted areas of extreme erosion, also shown by the deteriorated profiles, are indicators for anticipated vanes and blades failures.

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