1、A Status Report on Multiphase CFD for Gas-Particles Systems,Dr. Thomas J. OBrien National Energy Technology Laboratory (NETL) Morgantown, WV 2005 ANNUAL MEETING OF THE CHEMICAL REACTION ENGINEERING LABORATORY (CREL) Thursday, October 6, 2005 Washington University,The US will need to rely on fossil f
2、uels for electricity and transportation fuels well into 21st centuryIt is prudent to rely on a diverse mix of energy resourcesBetter technology can make a difference in meeting environmental needs at acceptable cost,NETL Three Premises,l.doe.gov www.fe.doe.gov,Outline,Hierarchy of modelsEulerian-Eul
3、erian approachFundamental set of equationsConstitutive lawsExamples,Outline,Hierarchy of modelsEulerian-Eulerian approachFundamental set of equationsConstitutive LawsExamples,Integrity with 3-D model Schematic diagrams P&IDs Loop diagrams Structural Report generation Reduce rework Standards/Specific
4、ations,CAD/CAE Modeling,Process Optimization Economic Evaluation Component Sizing Sensitivity AnalysisUnit Operations Library Physical Properties Database,Process Simulation,Normal operation Start-Up/Shut-Down Load-Following Transients Upsets Safety .,Control Systems,tightly coupled systems with dis
5、parate time scales,CFD Simulations single/multi-phase heat transfer chemical reactionsFinite Element Structural SimulationsEvent Based SimulationsMaterial/Property Simulations,Mechanistic Modeling,Hierarchy of Models,Enterprise System Models Integrated Models Component Modelsempirical modelsphysics
6、based models: CFD,Hierarchy of CFD models - 1,Single-phase fluid Continuum hydrodynamics (stress-law: ideal gas, ) Turbulence model (steady-state, turbulent stress, etc.) Heat transfer Chemical kinetics (global/mechanistic, homogeneous)Single-phase granular flow Discrete Element Method (DEM) Soft pa
7、rticle (enduring collisions) Hard particle (instantaneous, binary collisions) Continuum hydrodynamics (stress-law: kinetic theory, ) Turbulence model (not well developed!) Heat transfer Chemical kinetics,Hierarchy of CFD models - 2,Multiphase Eulerian-Lagrangian Eulerian non-interacting particles Eu
8、lerian - DEM Eulerian-Eulerian Continuum hydrodynamics (stress-law: ideal gas, ) Turbulence model (steady-state, turbulent stress, etc.) Heat transfer Chemical kinetics (global/mechanistic, homogeneous),Outline,Hierarchy of CFD modelsEulerian-Eulerian approachFundamental set of equationsConstitutive
9、 LawsExamples,Local variables Navier-Stokes eq. for fluid Newtons Laws for particles,Mean variables Navier-Stokes-like eqs.for fluid and granular phases,Outline,Hierarchy of CFD modelsEulerian-Eulerian approachFundamental set of equationsConstitutive LawsExamples,E-E Multiphase Model Equations,Conti
10、nuity Equations,Momentum Equations,Interaction Term,Stresses,Chemical Rates,Cascade of Energy,Single-phase flow Large scale fluid flow Small scale fluid flow Molecular dissipation,Cascade of Energy,Fluid-particle flowLarge scale fluid flow Small scale fluid flow Molecular dissipation Large scale par
11、ticle motion (bubbles/clusters) Relative particle motion (granular temp) Inelastic particle collisions ,Energy Balance,Outline,Hierarchy of CFD modelsEulerian-Eulerian approachFundamental set of equationsConstitutive Laws: closure dependence on mean variables Examples,Constitutive Laws: Phase Intera
12、ction,BouyancyDragLift,Fml is:1) empirical2) function of: velocity, voidage, ,Constitutive Laws: Granular Stresses,Multiphase Model - Granular Stress,Plastic Regime (Schaeffer 1987),Viscous Regime (Lun et al. 1984),Multiphase Model - Granular Stress Viscous Regime,Granular Temperature,Granular Press
13、ure,Shear Stress,Multiphase Model - Granular Stress Plastic Regime,Second Invariant of the Deviator of the Strain Rate Tensor,Pressure,Shear Stress,Outline,Hierarchy of CFD modelsEulerian-Eulerian approachFundamental set of equationsConstitutive LawsExamples,Modeling of Gas-Solid Transport in the Ch
14、emical Industry,The Goal is Fully Coupled SimulationsDense Phase Gas/Fluid Hydrodynamics Heat and Mass Transfer Chemical Kinetics 3-D TransientApplications: coal gasification, O3, SiH4, SiHCl3, CH4,TiCl4, -CH2-,MFDRC - NETL MFIX Code,MFIX - Multiphase Granular Flow CodeMFIX Application - Ozone Decom
15、position Fryer and Potter (1976) 117 mm, 2650 kg/m3 catalyst particles 0.229 m diameter x 2 m height bed height = 0.115 m Umf = 1.7 cm/s Gas flow: 2, 4, 6, 8, 10, 12, 14 cm/s axisymmetric cylindrical coordinates Grid resolution: 36 x 56, 72 x 112, 144 x 224 First order kineticsO3 - 1.5 O2 Catalyzed
16、by sand impregnated with iron oxide,MFIX Code - Ozone Decomposition,MFIX Code - Ozone Decomposition,U = 8 cm/s; Hmf = 11.5 cm,SiH4 Pyrolysis,“Silicon Deposition from Silane and Disilane in a Fluidized Bed - Part I: Experimental Study” B. Caussat, M. Hemati, and J. P. Couderc Chem. Eng. Sci., 50, 361
17、5-3624, 1995 - Part II: Theoretical Analysis and Modeling” Chem. Eng. Sci., 50, 3625-3635, 1995,Hydrogenation of SiCl4,“Investigation of the Hydrochlorination of SiCl4” Final Report JPL Contract No. 9506061, 1981-1983 J. Y. P. Mui, Solarelectronics, Inc.Process for the hydrochlorination of SiCl4 wit
18、h H2 to form SiHCl3 in a fluidized bed of Si (m.g.)Pseudo-first order JPL data being analyzed by Dow Corning personnel,Hydrogenation of SiCl4,Coal Gasification: Carbonizer Chemistry,Ash,Moisture,Volatile Matter,Fixed Carbon,CaO,CaCO3,CaMg(CO3)2,MgO,CO2 + H2O + CO + CH4 + H2 +Tar,CO2 + H2O + CO +CH4
19、+ H2 + Fixed Carbon,CO2 + H2O,O2,O2,coal,sorbent,H2O,CO + H2O CO2 + H2,CO2,O2,CO2,CO2,CO,H2O,H2 + CO,H2,CH4,Power Systems Development Facility Kellogg, Brown & Root Transport Reactor,Transient, 3-D cylindrical coordinated250K computational cells8 gas species: O2, CO, CO2, CH4, H2, H2O, N2, Tar4 soli
20、d species: Ash, Volatile Matter, Moisture, Fixed CarbonParallel runs at Pittsburgh Super Computing Center (PSC) week CPU time 10 seconds of simulation,80,Voidage,T_g,CO,CO2,O2,CH4,H2,H2O,Powder River Basin Coalair and oxygen blownwith/without lower mixing zoneHiawatha Coalair and oxygen blownwith lo
21、wer mixing zone,#Niksa Energy Associates,Simulations using PC Coal Lab# to determine yields and composition of volatile matter,MFIX Code: General Description www.mfix.org,(Multiphase Flow with Interphase eXchanges) general-purpose computer code developed at the National Energy Technology Laboratory
22、(NETL) describes the hydrodynamics, heat transfer and chemical reactions in fluid-solids systems used for describing bubbling and circulating fluidized beds and spouted beds calculations give transient data on the three-dimensional distribution of pressure, velocity, temperature, and species mass fr
23、actions used as a “test-stand“ for testing and developing multiphase flow constitutive equations.,MFIX Features,Mass, momentum, energy and species balance equations for gas and multiple solids phases Granular stress equations based on kinetic theory and frictional flow theory Three-dimensional Carte
24、sian or cylindrical coordinate systems with nonuniform mesh size Impermeable and semi-permeable internal surfaces,MFIX Features (cont.),Set up the simulation with an input data file Define chemical reactions and kinetics with the input data file or with a user-defined subroutine Error checking of us
25、er input Multiple, single-precision, binary, direct-access output files that reduces disk space and increases data retrieval speed Post-processing codes for the animation and retrieval of output data Fortran 90 code base with allocatable arrays Generate serial, shared-memory parallel (SMP) or distri
26、buted-memory parallel (DMP) executables from the same code base,Acknowledgements,Dr. Madhava Syamlal (NETL-DOE) Dr. Chris Guenther (NETL-DOE) Philip Nicoletti (NETL-Parsons) Dr. Sreekanth Pannala (DOE-ORNL) Dr. Sofiane Benyahia (NETL-Fluent, Inc.) Dr. Aytekin Gel (Aeolus Research, Inc.)Prof. Sankar Sundaresan (Princeton U.) Prof. Rodney Fox (Iowa State U.)Dr. Bill Rogers (DOE-FE-NETL),
