$$$$ FLAM NOTICE CHAT 11/09/12 21:16:15 7124 DATE 11/09/12 Operateur FLAM Voir aussi : -------------- 1a) ZH2 ZO2 ZN2 ZH2O Q = FLAM | 'EBU' | RHO CV MOT1 R YH2 YO2 YN2 | 'LAMINAIR' | YH2O T Dt | K E YH2u C_EBU (C0) | ; | | 1b) RCHPO1 RCHPO2 RCHPO3 RCHPO4 = 'FLAM' 'HEAVYSID' CHPO1 FLOT1 FLOT2 FLOT3 CHPO2 CHPO3 CHPO4 CHPO5 ; 1c) RCHPO1 RCHPO2 RCHPO3 RCHPO4 = 'FLAM' 'ARRHENIU' CHPO1 FLOT1 FLOT2 FLOT3 FLOT4 FLOT5 FLOT6 FLOT7 FLOT8 CHPO2 CHPO3 CHPO4 CHPO5 ; 2a) RCHPO1 = 'FLAM' 'CREBCOM' MOD1 FLOT1 FLOT2 CHPO1 ; 2b) RCHPO1 RCHPO2 = 'FLAM' 'CREBCOM2' MOD1 TAB2 LMOT1 LREE1 CHPO1 CHPO2 CHPO3 CHPO4 CHPO5 FLOT1 FLOT2 FLOT3 ; DESCRIPTION: ____________ 1) This operator integrates from time tn to time tn+1=tn+Dt a system of ordinary differential equations which model the time evolution of mass fractions of hydrogen, oxygen, nitrogen and water vapor following the global reaction, 2 H_2 + O_2 ---> 2 H_2O Thus, one solves from tn et tn+1, dYH2/dt = C_H2 omega(...) dYO2/dt = C_O2 omega(...) dYH2O/dt = C_H2O omega(...) where C_H2, C_O2, C_H2O are constants which depend on the stoichiometric coefficients of the reaction and the molar masses of the constituents, and omega the reaction rate. Note that nitrogen is a neutral species. Depending on the option, the reaction rate is given by a kinetic rate adapted to combustion in the laminar regime, or for turbulent regime by an Eddy Break-Up modele (EBU), or by a general Arrhenius rate adapted to the detonation regime (user defined coefficients), or by a infinitely fast combustion if temperature is greater than a threshold temperature (HEAVYSID). 2) "CREBCOM" criterion to follow the flame front Comments: _________ 1a) 'LAMINAR', 'EBU' ZH2 : mass fraction of H2 at time tn+1 (CHPOINT) ZO2 : mass fraction of O2 at time tn+1 (CHPOINT) ZN2 : mass fraction of N2 at time tn+1 (CHPOINT) ZH2O : mass fraction of H2O at time tn+1 (CHPOINT) Q : reaction heat release (CHPOINT) RHO : mixture density (CHPOINT) CV : specific heat at constant vol. (CHPOINT) MOT1 : temperature dependence of CV ('LINEAIRE' OR 'QUADRATI') R : mixture gas constant (CHPOINT) YH2 : mass fraction of H2 at time tn (CHPOINT) YO2 : mass fraction of O2 at time tn (CHPOINT) YN2 : mass fraction of N2 at time tn (CHPOINT) YH2O : mass fraction of H2O at time tn (CHPOINT) T : mixture temperature (CHPOINT) Dt : time step (REEL) K : turbulent kinetic energy (CHPOINT) E : dissipation rate of K (CHPOINT) YH2u : initial mass fraction of H2 (CHPOINT) C_EBU : Eddy Break-up constant (REEL) C0 : thresold (default 1.d-4) (REEL) : Yh2/Yh2u > 1-C0 -> Q=0 ; Yh2/Yh2u < C0 -> Yh2=0 1b) 'HEAVYSID' CHPO1 : CHPOINT containing the threshold temperature (in K; one component, 'SCAL'). FLOT1 : FLOTTANT containing the enthalpy of H2 at 0K (in J/kg) FLOT2 : FLOTTANT containing the enthalpy of O2 at 0K (in J/kg) FLOT3 : FLOTTANT containing the enthalpy of H2O at 0K (in J/kg) CHPO2 : CHPOINT containing the mass density of H2 (kg/m^3; one component, 'H2 ') CHPO3 : CHPOINT containing the mass density of O2 (kg/m^3; one component, 'O2 ') CHPO4 : CHPOINT containing the mass density of H2O (kg/m^3; one component, 'H2O ') CHPO5 : CHPOINT containing the temperature (K; one component, 'SCAL'). RCHPO1 : CHPOINT containing the mass density of H2 after the combustion (kg/m^3, one component, 'H2 ') RCHPO2 : CHPOINT containing the mass density of O2 after the combustion (kg/m^3; one component, 'O2 ') RCHPO3 : CHPOINT containing the mass density of H2O after the combustion (kg/m^3; one component, 'H2O ') RCHPO4 : CHPOINT containing the heat of reaction (in J/m^3; one component, 'SCAL'). 1c) 'ARRHENIU' CHPO1 : CHPOINT containing the threshold temperature (in K; one component, 'SCAL'). FLOT1 : FLOTTANT containing A (in I.S. units) FLOT2 : FLOTTANT containing b FLOT3 : FLOTTANT containing c FLOT4 : FLOTTANT containing the activation temperature Ta (in K) FLOT5 : FLOTTANT containing the enthalpy of H2 at 0K (in J/kg) FLOT6 : FLOTTANT containing the enthalpy of O2 at 0K (in J/kg) FLOT7 : FLOTTANT containing the enthalpy of H2O at 0K (in J/kg) FLOT8 : FLOTTANT containing the time step (in s) CHPO2 : CHPOINT containing the mass density of H2 (kg/m^3; one component, 'H2 ') CHPO3 : CHPOINT containing the mass density of O2 (kg/m^3; one component, 'O2 ') CHPO4 : CHPOINT containing the mass density of H2O (kg/m^3; one component, 'H2O ') CHPO5 : CHPOINT containing the temperature (K; one component, 'SCAL'). RCHPO1 : CHPOINT containing the mass density of H2 after the combustion (kg/m^3, one component, 'H2 ') RCHPO2 : CHPOINT containing the mass density of O2 after the combustion (kg/m^3; one component, 'O2 ') RCHPO3 : CHPOINT containing the mass density of H2O after the combustion (kg/m^3; one component, 'H2O ') RCHPO4 : CHPOINT containing the heat of reaction (in J/m^3; one component, 'SCAL'). 2a) 'CREBCOM' MOD1 : MODELE object. FLOT1 : the "epsilon" parameter in the CREBCOM criterion FLOT2 : maximum value of the reaction progress variable CHPO1 : reaction progress variable (CHAMPOINT object) RCHPO1 : CHAMPOINT object; it is 1 in the flame region, 0 elsewhere (one component, 'SCAL') 2b) 'CREBCOM2' MOD1 : MODELE object TAB2 : gas properties table (see 'PRIM' operator) LMOT1 : LISTMOTS containing the names of the gas components acting in the considered chemical reaction LREE1 : LISTREEL containing the stoichiometric coefficients of the considered chemical reaction (they are positive if referred to reactants, negative if referred to products; in the same order as LMOT1) CHPO1 : CHPOINT containing the mass density (one component, 'SCAL', geometric support SPG = 'DOMA' MOD1 'CENTRE') CHPO2 : CHPOINT containing the mass fraction of the species in LMOT1 (SPG = 'DOMA' MOD1 'CENTRE') CHPO3 : CHPOINT containing the initial mass fractions of the first species in LMOT1 (the same name as the first species in LMOT1, SPG = 'DOMA' MOD1 'CENTRE') CHPO4 : CHPOINT containing the final mass fractions of the first species in LMOT1 (the same name as the first species in LMOT1, SPG = 'DOMA' MOD1 'CENTRE') CHPO5 : CHPOINT containing the flame characteristic speed (one component, 'SCAL, SPG = 'DOMA' MOD1 'CENTRE') CHPO6 : CHPOINT containing the mesh dimension (one component, 'SCAL, SPG = 'DOMA' MOD1 'CENTRE') FLOT1 : FLOTTANT, "epsilon" parameter of CREBCOM criterion FLOT2 : FLOTTANT, time step FLOT3 : FLOTTANT, parameter to check the progress variable. If the progress variables is smaller than (-FLOT3) or larger than (1+FLOT3), an error message is given. RCHPO1 : CHPOINT, total energy per unit volume increment after the chemical reaction (one component, 'SCAL', SPG = 'DOMA' MOD1 'CENTRE') RCHPO2 : CHPOINT, mass densities increment of the species because of the chemical reaction (same name as LMOT1, SPG = 'DOMA' MOD1 'CENTRE') Remarks: ________ 'LAMINAIR' Combustion of hydrogen in the laminar regime, with reaction rate given by the global kinetic rate, omega = C1 RHO^2 YH2 YO2 exp(-C2/T) where C1 and C2 are predefined constants. 'EBU' Combustion of hydrogen in the turbulent regime, with reaction rate given by the Eddy Break-Up model (EBU), omega = C_EBU (E/K) YH2 ( 1 - YH2/YH2u )/(2MH2) where MH2 is the molar mass of hydrogen. 'HEAVYSID' Combustion of hydrogen with the reaction rate given by a omega = +oo si (T>Ts) omega = 0 sinon i.e. if T>Ts the combustion is infinitely fast. 'ARRHENIU' Combustion of hydrogen with the reaction rate given by a general Arrhenius reaction rate of the form: omega = A T^-b RHO_H2^c RHO_O2 exp (-Ta/T) if (T>Ts) omega = 0 else 'CREBCOM', 'CREBCOM2' CREBCOM combustion model (developed by Kurchatov Institute). In the case 'CREBCOM2' we check the positivity of the density, the mass fractions and of the characteristic velocity. Moreover we check that the progress variable varies between 0 and 1.
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