FDS Source: Experimental CFT

Author: mcgratta

Manuals/FDS_User_Guide/FDS_User_Guide.tex

@@ -11794,7 +11794,7 @@ \chapter{Alphabetical List of Input Parameters}
 
 % ignore namelist/keyword combinations
 % ignorenamelistkw: /BNDF/DEBUG
-% ignorenamelistkw: /COMB/FUEL_ID_FOR_AFT, /COMB/USE_MIXED_ZN_AFT_TMP
+% ignorenamelistkw: /COMB/FUEL_ID_FOR_AFT, /COMB/USE_MIXED_ZN_AFT_TMP, /COMB/VARIABLE_CFT
 % ignorenamelistkw: /DEVC/ELEM_ID, /DEVC/STATISTICS
 % ignorenamelistkw: /DUMP/MMS_TIMER, /DUMP/TURB_INIT_CLOCK, /DUMP/GET_CUTCELLS_VERBOSE, /DUMP/WRITE_CVODE_SUBSTEPS
 % ignorenamelistkw: /HVAC/DEBUG

Source/cons.f90

@@ -448,6 +448,7 @@ MODULE GLOBAL_CONSTANTS
 LOGICAL :: OUTPUT_CHEM_IT=.FALSE.
 LOGICAL :: REAC_SOURCE_CHECK=.FALSE.
 LOGICAL :: COMPUTE_ADIABATIC_FLAME_TEMPERATURE=.FALSE.              !< Report adiabatic flame temperature per REAC in LU_OUTPUT
+LOGICAL :: VARIABLE_CFT=.FALSE.                                     !< Experimental critical flame temp concept
 
 REAL(EB) :: RSUM0                                     !< Initial specific gas constant, \f$ R \sum_i Z_{i,0}/W_i \f$
 

Source/fire.f90

@@ -996,7 +996,7 @@ SUBROUTINE COMBUSTION_MODEL(T,DT,ZZ_GET,Q_OUT,MIX_TIME_OUT,CHI_R_OUT,CHEM_SUBIT_
 IF (SUPPRESSION .AND. .NOT.EXTINCT) THEN
    SELECT CASE(EXTINCT_MOD)
       CASE(EXTINCTION_1); CALL EXTINCT_1(EXTINCT,ZZ_0,TMP_IN)
-      CASE(EXTINCTION_2); CALL EXTINCT_2(EXTINCT,ZZ_0,ZZ_MIXED,TMP_IN)
+      CASE(EXTINCTION_2); CALL EXTINCT_2(EXTINCT,ZZ_0,ZZ_MIXED,TMP_IN,TAU_MIX)
    END SELECT
 ENDIF
 
@@ -1417,10 +1417,10 @@ END SUBROUTINE EXTINCT_1
 !> \param ZZ_IN Array of lumped species mass fractions in the mixed part of the grid cell at the end of the time step
 !> \param TMP_IN Initial temperature of the grid cell
 
-SUBROUTINE EXTINCT_2(EXTINCT,ZZ_0,ZZ_IN,TMP_IN)
+SUBROUTINE EXTINCT_2(EXTINCT,ZZ_0,ZZ_IN,TMP_IN,TAU_MIX)
 
 USE PHYSICAL_FUNCTIONS, ONLY: GET_ENTHALPY
-REAL(EB),INTENT(IN) :: TMP_IN,ZZ_IN(1:N_TRACKED_SPECIES),ZZ_0(1:N_TRACKED_SPECIES)
+REAL(EB),INTENT(IN) :: TMP_IN,ZZ_IN(1:N_TRACKED_SPECIES),ZZ_0(1:N_TRACKED_SPECIES),TAU_MIX
 LOGICAL, INTENT(INOUT) :: EXTINCT
 REAL(EB) :: ZZ_HAT_0(1:N_TRACKED_SPECIES),ZZ_HAT(1:N_TRACKED_SPECIES),H_0,H_CRIT,PHI_TILDE,CFT
 INTEGER :: NS,NR
@@ -1443,7 +1443,11 @@ SUBROUTINE EXTINCT_2(EXTINCT,ZZ_0,ZZ_IN,TMP_IN)
    RETURN
 ENDIF
 
-CFT = SUM_CFT/SUM_ZZ
+IF (VARIABLE_CFT) THEN
+   CFT = 1522.1_EB*(1000._EB*TAU_MIX)**(-0.038_EB)  ! Experimental mechanism, U of Ghent
+ELSE
+   CFT = SUM_CFT/SUM_ZZ
+ENDIF
 
 ! Compute the modified cell equivalence ratio
 

Source/read.f90

@@ -4522,7 +4522,7 @@ SUBROUTINE READ_COMB
                 EXTINCTION_MODEL,FINITE_RATE_MIN_TEMP, FIXED_MIX_TIME,FREE_BURN_TEMPERATURE, &
                 FUEL_ID_FOR_AFT,INITIAL_UNMIXED_FRACTION, MAX_CHEMISTRY_SUBSTEPS, MAX_EQUIV_RATIO, MIN_EQUIV_RATIO, &
                 N_FIXED_CHEMISTRY_SUBSTEPS, ODE_MIN_ATOL,ODE_REL_ERROR,ODE_SOLVER,SUPPRESSION,TAU_CHEM, &
-                TAU_FLAME,TURBULENT_FLAME_SPEED,RAMP_ZETA_0,USE_MIXED_ZN_AFT_TMP,ZZ_MIN_GLOBAL
+                TAU_FLAME,TURBULENT_FLAME_SPEED,RAMP_ZETA_0,USE_MIXED_ZN_AFT_TMP,VARIABLE_CFT,ZZ_MIN_GLOBAL
 
 ODE_SOLVER    = 'null'
 ODE_REL_ERROR = -1._EB