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ABSTRACT
Properly describing turbulence-complex reaction interactions is crucial for predicting turbulent combustion and pollutant emission. A presumed probability density function model for temperature fluctuation is adopted in the present paper. It incorporates a 25-step skeletal mechanism for methane combustion. The gas turbulent transport is simulated with the algebraic Reynolds stress model for turbulence-swirl interactions. These models are applied to the simulation of swirl-stabilized turbulent partially premixed jet flame. The calculated gas velocities, fluctuating velocities, Reynolds shear stresses, temperature, and species mass fractions are in agreement with the measured test data.
Nomenclature
| Bi | = | pre-exponential factor |
| Cg1, Cg2 | = | turbulence model constants |
| = | mean specific heat capacity (J/kg K) | |
| D | = | diameter of bluff body (m) |
| Ei | = | activation energy (J/mol) |
| h | = | enthalpy (J/kg) |
| h0 | = | enthalpy of formation (J/kg) |
| hs | = | sensible enthalpy (J/kg) |
| k | = | turbulent kinetic energy (m2/s2) |
| kfall | = | fall-off rate |
| mi, ni | = | density and temperature exponents |
| M | = | molecular weight (kg/mol) |
| n | = | species number |
| p | = | static pressure (Pa or atm) |
| r | = | radial distance from axis (m) |
| R | = | universal gas constant (J/mol K) |
| SΦ | = | generalized source term |
| T | = | temperature (K) |
| Tm | = | adiabatic combustion temperature at stoichiometric condition for the fuel (K) |
| T0 | = | minimum temperature of combustion system (K) |
| T0 | = | reference temperature (298.15 K) |
| u, v, w | = | axial, radial, and tangential velocities (m/s) |
| W | = | reaction rate for each step (kg/m3 s) |
| x | = | axial distance from burner exit (m) |
| Y | = | species mass fraction |
| α, γ, η+, η− | = | parameters in presumed PDF |
| αΦ | = | generalized coefficient |
| βi | = | coefficient in the ith step reaction rate |
| ΓΦ | = | generalized effective transport coefficient |
| ε | = | dissipation rate of turbulent kinetic energy (m2/s3) |
| η | = | nondimensional temperature |
| ηl | = | third body efficiency of species l |
| μ | = | dynamic viscosity (kg/m s) |
| ρ | = | density (kg/m3) |
| σg | = | turbulent Schmidt number |
| Φ | = | generalized variable |
| Subscripts | = | |
| e | = | effective |
| k | = | species |
| M | = | third body |
| r | = | radial coordinate, reactant |
| t | = | turbulent |
| x | = | axial coordinate |
| Superscripts | = | |
| i | = | ith step reaction |
| ′ | = | fluctuation quantity |
| — | = | time-averaged quantity |
Nomenclature
| Bi | = | pre-exponential factor |
| Cg1, Cg2 | = | turbulence model constants |
| = | mean specific heat capacity (J/kg K) | |
| D | = | diameter of bluff body (m) |
| Ei | = | activation energy (J/mol) |
| h | = | enthalpy (J/kg) |
| h0 | = | enthalpy of formation (J/kg) |
| hs | = | sensible enthalpy (J/kg) |
| k | = | turbulent kinetic energy (m2/s2) |
| kfall | = | fall-off rate |
| mi, ni | = | density and temperature exponents |
| M | = | molecular weight (kg/mol) |
| n | = | species number |
| p | = | static pressure (Pa or atm) |
| r | = | radial distance from axis (m) |
| R | = | universal gas constant (J/mol K) |
| SΦ | = | generalized source term |
| T | = | temperature (K) |
| Tm | = | adiabatic combustion temperature at stoichiometric condition for the fuel (K) |
| T0 | = | minimum temperature of combustion system (K) |
| T0 | = | reference temperature (298.15 K) |
| u, v, w | = | axial, radial, and tangential velocities (m/s) |
| W | = | reaction rate for each step (kg/m3 s) |
| x | = | axial distance from burner exit (m) |
| Y | = | species mass fraction |
| α, γ, η+, η− | = | parameters in presumed PDF |
| αΦ | = | generalized coefficient |
| βi | = | coefficient in the ith step reaction rate |
| ΓΦ | = | generalized effective transport coefficient |
| ε | = | dissipation rate of turbulent kinetic energy (m2/s3) |
| η | = | nondimensional temperature |
| ηl | = | third body efficiency of species l |
| μ | = | dynamic viscosity (kg/m s) |
| ρ | = | density (kg/m3) |
| σg | = | turbulent Schmidt number |
| Φ | = | generalized variable |
| Subscripts | = | |
| e | = | effective |
| k | = | species |
| M | = | third body |
| r | = | radial coordinate, reactant |
| t | = | turbulent |
| x | = | axial coordinate |
| Superscripts | = | |
| i | = | ith step reaction |
| ′ | = | fluctuation quantity |
| — | = | time-averaged quantity |