شبيه سازي عددي جريان براي يك جداكننده جامد-گاز با بافل ها

چكيده انگليسي :

Numerical Flow Simulation for a Gas Solid Separator With Baffles Ehsan Dehdarinezhad e dehdarinezhad@me iut ac ir October Department of Mechanical engineering Isfahan University of Technology Isfahan IranDegree M Sc Language FarsiSupervisor Ahmad sedaghat sedaghat@cc iut ac irAbstractParticles movement in laminar and turbulent flows has a lot of applications for combustion biological environmentaland nanotechnology systems Wearing out by contacting solid particles is an important issue in charcoal combustionsystem and in separation lines of escaping charcoal Therefore understanding of this field including contact and deposit separating solid particles from gas flow to design engineering devices is vital It is necessary to have separator devicewith remaining time less than one second to separate solid particles from combustion reaction in risers and downers Experimental results showed that the CBQSD model has many benefits such as high efficiency low pressure loss andsymmetrical and compact structure In this study one separator of solid gas flow that is called Combined Baffle QuickSeparator Device CBQSD is simulated by FLUENT FLUENT is very important industrial software to simulate fluidflows This software is able to simulate and dimensional fluid flows In this research turbulence models of RSM and Lagrange model to trail particles are considered Dual way phase coupling is used tosolve particles flows By changing parameters such as inlet Reynolds number and the device geometry numerical resultsare compared with experimental data and then the optimized condition for separating particles is introduced Numericalanalyses show RNG is not an efficient model because it failed to show the correct amount of average speed Thismodel could not reveal exactly vortex and flow separating that is occurred by existing separator baffles and guides inchamber model shows better result than the previous model This model displays particles speed more accuratelyand simulates flow near the wall more reasonable than previous model although this model could not show particledistribution on baffles Finally using the five equations Reynolds Stress Model RSM better results was obtained Theresult from this model was compared in better agreement with experimental data for velocity and distribution ofparticles It is concluded that this model is a better model to consider for this device A parametric study was conductedbased on inlet velocity device width distance between the guide baffles and the separator and inlet flow rate ofparticles to the chamber The results show that by increasing velocity efficiency grows remarkably It is noticeable thatincreasing velocity may cause more cost and may require more facility so that high speed is not recommended for use inindustrial Efficiency decreases due to growing particles diameter sizes because particles do not have enough time toseparate from flow field and they are consequently going out by stream Increasing particle diameter improves efficiencybut more increase may cause lesser increase of efficiency because of a violent inverse flow occurs in separator baffles The results show that the best efficiency is obtained when particles with small diameter used whilst flow rate increases Total efficiency of device remains around and it changes infinitesimally Key WordsGas Solid Flow Particle Separator Baffle

دهداري نژاد، احسان

شبيه سازي عددي جريان براي يك جداكننده جامد-گاز با بافل ها

مدل ذرات گسسته , مدل توربولانس , لاگرانژين