PAMM · Proc. Appl. Math. Mech. 6, 547–548 (2006) / DOI 10.1002/pamm.200610254
Particle-Laden Flow Simulation in a Cyclone Separator
Hemdan Shalaby1,Klaus Wozniak2,and G¨unter Wozniak∗3
1Laboratory of Fluid Mechanics and Technical Flows,University of Magdeburg’Otto von Guericke’,Universit¨a tsplatz2
D-39106Magdeburg,Germany
2SIVUS gGmbH,Schulstr.38D-09125Chemnitz,Germany
3Chemnitz University of Technology,Chair of Fluid Mechanics,Straße der Nationen62D-09107Chemnitz,Germany脸皮薄
The particle-ladenflow of a cyclone parator for industrial applications at a Reynolds number of Re=140,000has been
studied numerically.Due to the nature of cycloneflows,which exhibit highly curved streamlines and anisotropic turbu-
lence,we ud the advanced turbulence model Large Eddy Simulation(LES).Our LES reveals qualitative agreement with
experimental data,but requires higher computer capacity and longer running times compared to other turbulence models.The
results of the continuous phaflow computations were generatedfirst and rved as a basis for modeling the behavior of solid
particles in the parator.Modeling of the solid particle motion in the cyclone was performed applying a one-way coupling
between the gasflowfield and the particles.The cyclone paration efficiency and particle trajectories have been studied in
detail.Separation efficiency results show satisfying agreement between LES data and experimental results.It turned out that
the particle cut-off diameter for a particle material density of2500kg/m3is approximately1.3µm.
© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1Introduction
A cyclone parator is a device,which caus centrifugal paration of disperd pha materials in afluidflow.Computational fluid dynamics CFD has become a widely accepted design tool for rearch and development influid mechanics over the last decade.Frank et al.[1]developed a3-dimensional Eulerian-Lagrangian approach(MISTRAL/PartFlow-3D)for the numerical prediction of gas-particleflows.Recently,Shalaby et al.[2]carried out numerical calculations at the apex cone at various axial positions of a gas cyclone parator for industrial applications.Their work was bad on the comparison between three turbulence models,k− ,RSM(Reynolds Stress Models)and LES.The authors found that the application of the LES reveals a better agreement with experimental data.The objective of this study is to investigate the cyclone paration efficiency and particle trajectories by means of LES and an Eulerian-Lagrangian approach.
2Computational parameters
The cyclone parator under investigation is characterized by the geometrical properties shown in[2].The simulation pre-nted here has been carried out with the code MISTRAL/PartFlow-3D.The code is bad on afinite volume approach, implicit time steps and a cond-order central-differencin电脑相机
g scheme(CDS)for convection.Initially,500conquently decreas-ing time steps were performed in order to allow the cycloneflow to reach a fully developed state.The time step reached after the initial iterations was10−4s real(physical)time.The averaging process was started after the initial iterations and all mean characteristics of theflow have been obtained by averaging over35000time steps.The CFL number which defines the relation between the temporal and spatial discretization accuracy was0.85.Moreover,a cond order accurate implicit time scheme was ud in the study for temporal discretization.
3Results and discussions
3.1Cyclone paration efficiency
Separation efficiency is defined as the fraction of particles of any given size that are retained by the cyclone.The prediction of the particle paration efficiency has been carried out in accordance to[3].The quartz dust ud as particle material had a particle diameter distribution in the range of=0to50µm with a mean particle diameter of10.9µm.The numerical computations were carried out for20particle diameter class in the range between0.5and15µm.A particle density of 2500kg/m3was assumed.Figure1shows the comparison of the predicted paration efficiency with the experimental
results of[3].It shows satisfying agreement between LES and experimental results.The shapes of the efficiency curves are almost identical.
∗Corresponding author:e-mail:guenter.wozniak@mb.tu-chemnitz.de,Phone:+4903715311543,Fax:+4903715311847
怎么表白男生Particle diameter (m)S e p a r a t i o n e f f i c i e n y
Fig.1Comparison of predicted cyclone paration efficiency with experimental data [3].
a b c
Fig.2Particle trajectories with residence time (in conds)at different particle diameters of 0.5(a),1.0(b)and 1.3(c)µm .
手机烫3.2Particle trajectories
Figure 2shows examples of particle trajectories including residence time indication in the cyclone.Figure 2(a)shows a smaller particle,which is captured by the condary flow along the cyclone lid and follows the condary flow along the wall of the vortex finder tube to the gas exit.Figure 2(b)shows a 1.0µm particle moving along the outer conical wall to the particle hopper.It follows the recirculating gas flow back into the cyclone body where it is parated and captured into the vortex core before it moves upward to the gas exit.A slightly larger particle of 1.3µm in Figure 2(c)is first captured in a particle rope along the cyclone lid.However,it is too large to follow the recirculating flow to the vortex finder tube.In the following it moves down to the particle hopper where it is collected.
4Concluding remarks
培根做法The nature of the particle-laden flows in cyclones is highly swirling with anisotropic turbulence.Therefore,advanced tur-bulence models such as LES have to be applied to predict the complex flow behavior.Our LES results compare well with experimental data found in the literature.This is one key result of the performed investigations.The gained LES results are very enco
uraging and have shown that this model is a better alternative to conventional turbulence modelling of cyclone p-arator flows.The LES results of the continuous pha flow are ud for modelling the solid particle motion in the cyclone In the flow field,solid particles of various sizes are relead to predict the cyclone paration efficiency.Here,we assumed also a one-way coupling between the gas pha and the particles.The predicted cyclone paration efficiency results of LES show satisfying agreement with experimental data.Sample particle trajectories in the cyclone have been prented and discusd.向下扎根
References
[1]T.Frank,Q.Yu,E.Wasn,and J.Schneider.Experimental and numerical investigation of particle paration in a symmetrical
double cyclone parator.Proceedings of the 19993rd ASME/JSME Joint Fluids Engineering Conference,FEDSM’99,San Francisco,California,USA,18-23July ,1999.
初一十五吃素[2]H.Shalaby,G.Wozniak,K.Pachler,and K.Wozniak.Comparative study of the continuous pha flow in a cyclone parator using
different turbulence models.Int.J.Numer.Meth.Fluids ,48(11):1175–1197,2005.
注射瘦脸针
[3] C.K¨o nig.Untersuchungen zum Abscheidverhalten von geometrisch ¨a hnlichen Zyklonen.Disrtation,Unversity of Kairslautern,
Germany ,1990.
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