1. CHEMKIN - A Tool for Reactor Model Simulation By Dr. Youngchul Ra ME-769 Combustion February 8, 2013 1

2. CHEMKIN (Many versions) -Reactor Models: industry specific reacting-flow conditions. -User Interface: user inputs and visual construction of reactor- network diagrams. -Built-in visualization options: graphic representation of results. 2

3. Reactor Models 3

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5. Theoretical Background -Species: species: gas-phase, surface (“sites”), and bulk. -Phases: Gas, condensed material, and solid. -Only gas-phase species participate in gas-phase reactions, but all types of species may participate in heterogeneous gas- surface reactions. -State variables define the thermodynamic and chemical state of the fluid mixture. -Equation od State -Specific heat capacity at constant pressure -Enthalpy -Entropy 5

6. Specific heat capacity Enthalpy Entropy Reversible reaction Production rate Rate of progress Forward rate constant Reverse rate constant 6

7. Homogeneous 0-D Reactor Models 1. Closed Homogeneous Reactor 2. Internal Combustion Engine 3. Closed Plasma Reactor 4. Perfectly Stirred Reactor (PSR) 5. Plasma Reactor 6. Multi-zone Engine Simulator Mass conservation + Atom conservation + Energy conservation + Equation of state 7

8. CHEMKIN INPUT: input parameters for a chemically reacting flow simulation -Syntax and format of chemical reaction mechanism input files -Thermodynamic data -Transport property data -Input parameters associated with reactor models  CHEMKIN Input Manual 8

9. Thermodynamic Data Format: “A specific format” -Fourteen polynomial fitting coefficients -Species' name, elemental composition, electronic charge, and phase (gas, solid, liquid or solid) Thermo.dat or Kinetics input file w/ “THERMO” 9

10. Each temperature interval consists of 7 coefficients 10

11. Gas-Phase Kinetics Input Format: “A specific format” -A symbolic description of an elementary chemical reaction mechanism -Used during Pre-processing to create a GAS-PHASE KINETICS linking file (chem.asc) -The linking file is accessed during the reactor-model simulation Element data: ELEMENTS (or ELEM) ….. END Species data: SPECIES (or SPEC) ….. END Thermodynamic data (optional): THERMO ….. END Transport data: TRANSPORT (or TRAN) ….. END Reactions: REACTIONS ….. END chem.inp 11

12. Transport Data Format: “A specific format” species name (first 16 columns), An index indicating geometrical configuration (0, 1 or 2) The Lennard-Jones potential well depth,  /k B The Lennard-Jones collision diameter,  The dipole moment,  The polarizability,  The rotational relaxation collision number, Z rot Tran.dat or Kinetics input file w/ “TRAN” 12

13. Keywords (Auxiliary) -Detailed information about input options for each Reactor Model. -Each input line starts with an identifying keyword. -Rules for keywords  Input manual Internal Combustion Engine Reactor Model: ADAP, ADD, AEXT, AROP, ASEN, ASTEPS, ATLS, ATOL, AVALUE, AVAR, BETA, CAATQ, CLSC, CLSM, CMPR, CNTN, CNTT, COLR, DEG0, DELT, DIST, DTDEG, DTIGN, DTSV, END, EPSR, EPSS, EPST, EQUI, FUEL, GFAC, GMHTC, GVEL, ICEN, ICHT, IPSR, KLIM, LOLR, MAXIT, MCUT, MMASS, NCANG, NEWRUN, NMOM, NNEG, NOCG, NRAW, NREV, NSOL, NTOT, OXID, PNDE, PRDL, PRES, PRNT, PROE, PVFE, QFUN, QLOS, QPRO, QRGEQ, REAC, RELAXC, ROP, RPM, RSTR, RTLS, RTOL, SCOR, SENT, SIZE, SOLUTION_TECHNIQUE, SSTT, STPT, TEMP, TIFP, TIME, TLIM, TRAN, TRES, TRST, TSTR, TTIM, UIGN, UREF, USET, VOLC, VOLD, WENG, XMLI 13

14. 1. Decide on your modeling approach -Network of reactor models or a single, well mixed zone or perfectly stirred reactor -A zero-dimensional or a 1- or 2-dimensional description of geometry. -From simpler models to more complex simulations. 2. Create a diagram of the reactor or reactor network. 3. Prepare or obtain and then pre-process your Chemistry Set, which consists of: GAS-PHASE KINETICS Input (SURFACE KINETICS Input) Species thermodynamic data (Gas-phase species transport data) 4. Set up the reactor and inlet conditions in the appropriate input panels, specifying: (Geometry) Process Conditions (Solution method options) (Parameter Study or Uncertainty Analysis options) 5. Create the project input files and solve the problem, which can mean: Run one case/one batch job/a Parameter Study/an Uncertainty Analysis 6. Analyze the results using one of the following methods: The CHEMKIN-PRO Post-Processor/The Reaction Path Analyzer/Export to Excel or text file Simulation of reactor models 14

15. User input -Parameter inputs: cluster-level, reactor-level, inlet-specific, solver-related parameters, output parameters, continuations management. -Run controls: Run Calculations, Run Parameter Study, Run Uncertainty Analysis, and Monitor panels Gas Flow: Connection from one open reactor to another. (mass flow rate, temperature and species composition) Initialization Recycle Flow 15

16. Test cases Perfectly stirred reactor: psr_gas Ignition delay calculation: closed_homogeneous_ignition_delay Internal combustion engine: ic_engine_hcci_heat_loss-methane Internal combustion engine: New project IC Engine specification nC7H160.018691 O2 0.205596 N2 0.775714 Initial composition (mole fraction) 16

17. 17 How to start CHEMKIN 1.Log into your CAE account. 2.Locate/Start CHEMKIN: -Start > All Programs > Course Software > A-F > CHEMKIN 4.1 > CHEMKIN Interface 4.1 -A few windows should appear then disappear, finally the CHEMKIN interface should appear and look something like this 3.You are now ready to run CHEMKIN. Note: Remote desktop access to CHEMKIN is not available any more. Accessible using CAE computers ONLY.

18. 18 CHEMKIN Demonstration