scholarly journals Numerical Simulation of Dense Gas-Solid Multiphase Flows Using Eulerian-Eulerian Two-Fluid Model

10.5772/24244 ◽  
2011 ◽  
Author(s):  
Teklay Weldeabzgi ◽  
Matthias Schreiber ◽  
Hans Joachim
Keyword(s):  
Numerical Simulation ◽  
Multiphase Flows ◽  
Fluid Model ◽  
Dense Gas ◽  
Two Fluid Model ◽  
Two Fluid

scholarly journals Multi-scale Eulerian-Lagrangian simulation of a liquid jet in cross-flow under acoustic perturbations

2017 ◽  
Author(s):  
Swann Thuillet ◽  
Davide Zuzio ◽  
Olivier Rouzaud ◽  
Pierre Gajan
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Fluid Model ◽  
Liquid Column ◽  
Pollutant Emissions ◽  
Liquid Jet ◽  
Acoustic Perturbation ◽  
Jet Trajectory ◽  
Two Fluid Model ◽  
Two Fluid

The design of modern aeronautical propulsion systems is constantly optimized to reduce pollutant emissions whileincreasing fuel combustion efficiency. In order to get a proper mixing of fuel and air, Liquid Jets Injected in gaseous Crossflows (LJICF) are found in numerous injection devices. However, should combustion instabilities appear in the combustion chamber, the response of the liquid jet and its primary atomization is still largely unknown. Coupling between an unstable combustion and the fuel injection process has not been well understood and can result from multiple basic interactions.The aim of this work is to predict by numerical simulation the effect of an acoustic perturbation of the shearing air flow on the primary breakup of a liquid jet. Being the DNS approach too expensive for the simulation of complex injector geometries, this paper proposes a numerical simulation of a LJICF based on a multiscale approach which can be easily integrated in industrial LES of combustion chambers. This approach results in coupling of two models: a two-fluid model, based on the Navier-Stokes equations for compressible fluids, able to capture the largest scales of the jet atomization and the breakup process of the liquid column; and a dispersed phase approach, used for describing the cloud of droplets created by the atomization of the liquid jet. The coupling of these two approaches is provided by an atomization and re-impact models, which ensure liquid transfer between the two-fluid model and the spray model. The resulting numerical method is meant to capture the main jet body characteristics, the generation of the liquid spray and the formation of a liquid film whenever the spray impacts a solid wall.Three main features of the LJICF can be used to describe, in a steady state flow as well as under the effect of the acoustic perturbation, the jet atomization behavior: the jet trajectory, the jet breakup length and droplets size and distribution.The steady state simulations provide good agreement with ONERA experiments conducted under the same condi- tions, characterized by a high Weber number (We>150). The multiscale computation gives the good trajectory of the liquid column and a good estimation of the column breakup location, for different liquid to air momentum flux ratios. The analysis of the droplet distribution in space is currently undergoing. A preliminary unsteady simulation was able to capture the oscillation of the jet trajectory, and the unsteady droplets generation responding to the acousticperturbation.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4697

Numerical Simulation of the Gas-Solid Flow in a Mini-Riser Reactor

2011 ◽  
Vol 396-398 ◽  
pp. 356-360
Author(s):  
Qun Shuai ◽  
Gen Lin Niu ◽  
Hui Zhao ◽  
Qiang Li
Keyword(s):  
Numerical Simulation ◽  
Kinetic Theory ◽  
Solid Phase ◽  
Fluid Model ◽  
Two Phase ◽  
Operational Conditions ◽  
Riser Reactor ◽  
Two Fluid Model ◽  
Two Fluid ◽  
As Solid Phase

The implementation of the kinetic theory for granular flows added strength to the two-phase flow model in the mini-riser. This model uses simulating and calculating commercial software of Fluent to simulate the mini-riser with 0.012m ID and 3m height. Euler-Euler two fluid model was adopted in two dimensional numerical simulation, according to kinetic theory，the solid stress was calculated based on granular temperature and granular viscosity obtained through simulation which could be used to describe the collision between particles. Simulation results, such as solid phase fraction and solid phase velocity, under different operational conditions basically agree well with the experimental measurement.

Practical validation of the two-fluid model applied to dense gas–solid flows in fluidized beds

2007 ◽  
Vol 62 (21) ◽  
pp. 5854-5869 ◽  
Author(s):  
HÅvard Lindborg ◽  
Magne Lysberg ◽  
Hugo A. Jakobsen
Keyword(s):  
Fluidized Beds ◽  
Fluid Model ◽  
Dense Gas ◽  
Two Fluid Model ◽  
Practical Validation ◽  
Two Fluid

scholarly journals Numerical Simulation of Size Effects on Countercurrent Flow Limitation in PWR Hot Leg Models

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
I. Kinoshita ◽  
M. Murase ◽  
A. Tomiyama
Keyword(s):  
Numerical Simulation ◽  
Size Effect ◽  
Numerical Simulations ◽  
Size Effects ◽  
Fluid Model ◽  
Flow Channel ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Two Fluid Model ◽  
Two Fluid

We have previously done numerical simulations using the two-fluid model implemented in the CFD software FLUENT6.3.26 to investigate effects of shape of a flow channel and its size on CCFL (countercurrent flow limitation) characteristics in PWR hot leg models. We confirmed that CCFL characteristics in the hot leg could be well correlated with the Wallis parameters in the diameter range of0.05 m≤D≤0.75 m. In the present study, we did numerical simulations using the two-fluid model for the air-water tests withD=0.0254 m to determine why CCFL characteristics forD=0.0254 m were severer compared with those in the range,0.05 m≤D≤0.75 m. The predicted CCFL characteristics agreed with the data forD=0.0254 m and indicated that the CCFL difference betweenD=0.0254 m and0.05 mm≤D≤0.75 mm was caused by the size effect and not by other factors.

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