TEXT(Premixed CH4 Combustion
TITLE
DISPLAY
The problem considered is turbulent reacting flow in a
cylindrical combustion chamber with central and annular
coaxial feed injectors supplying premixed methane and
air. The geometry is axisymmetric with an outer radius
of 0.21m and an axial length of 2.75m. The reactants are
supplied at a temperature of 300K, and the composition of
each inlet stream is identical. The default fuel/air
equivalence ratio is 1.15, and the operating pressure
is 1 bar.
ENDDIS
GROUP 1. Run title and other preliminaries
REAL(WINF,WINO,KEL,EPL,KEINIT,TWAL,TEMFU,TEMOX)
REAL(YFUIN,YOXIN,YN2IN,RTUBE);CHAR(CTUR,CMOD)
INTEGER(ICOMB,ICASE);BOOLEAN(HSOLV,THRAD);HSOLV=T;THRAD=F
WINF=27.18;WINO=6.418; RTUBE=0.21
TWAL=100.+273.;TEMFU=27.+273.;TEMOX=TEMFU
MESG( Enter required inlet stoichometry: default O2 excess
MESG( The options are:
MESG( O2 - Excess oxygen supply
MESG( ST - Stoichometric supply
MESG( FU - Excess fuel supply
READVDU(CTUR,CHAR,O2)
CASE :CTUR: OF
WHEN O2,2
+ MESG(Excess Oxygen supply : Equivalence Ratio = 1.15
+ YFUIN=0.04846;YOXIN=0.22165
+ ICASE=1
WHEN ST,2
+ MESG(Stoichometric supply : Equivalence Ratio = 1.0
+ YFUIN=0.0552;YOXIN=0.21986
+ ICASE=2
WHEN FU,2
+ MESG(Excess Fuel supply : Equivalence Ratio = 0.8
+ YFUIN=0.0679;YOXIN=0.21625
+ ICASE=3
ENDCASE
YN2IN=1.-YFUIN-YOXIN
GROUP 2. Transience; time-step specification
STEADY=T
GROUP 3. X-direction grid specification
CARTES=F;XULAST=0.1
GROUP 4. Y-direction grid specification
NREGY=4;NY=8
IREGY=1;GRDPWR(Y,2,0.0191,1.0);IREGY=2;GRDPWR(Y,2,0.0286,1.0)
IREGY=3;GRDPWR(Y,2,0.0548,1.0);IREGY=4;GRDPWR(Y,2,0.1048,1.0)
GROUP 5. Z-direction grid specification
NREGZ=2;NZ=10
IREGZ=1;GRDPWR(Z,4,0.381,1.0);IREGZ=2;GRDPWR(Z,6,2.362,1.3)
GROUP 7. Variables stored, solved & named
SOLVE(P1,V1,W1);STORE(VIST,DEN1,TMP1,SPH1,YSUM)
SOLUTN(P1,P,P,Y,P,P,P);SOLUTN(V1,P,P,P,P,P,N)
SOLUTN(W1,P,P,P,P,P,N);TURMOD(KEMODL)
IF(HSOLV) THEN
+ SOLVE(H1);TERMS(H1,N,P,P,P,P,P)
+ SOLUTN(H1,P,P,Y,P,P,P)
ELSE
+ STORE(H1)
ENDIF
IF(THRAD) THEN
+ REAL(ABSORB,SCAT,SIGMA,EMPW,EMISW,EMISG,EMPG)
+ ABSORB=1.45;SCAT=0.; EMISG=0.07
+ SIGMA=5.6697E-8; EMISW=1.0
+ EMPW=SIGMA*TWAL**4; EMPG=SIGMA*EMISG
+ RADIAT(RADI,ABSORB,SCAT,H1)
+ SOLUTN(SRAD,P,P,Y,P,P,P);SOLUTN(H1,P,P,Y,P,P,P)
ENDIF
GROUP 8. Terms (in differential equations) & devices
GROUP 9. Properties of the medium (or media).
ENUL=4.2E-5
*** START OF EXTENDED SCRS MODEL SETTINGS
PRESS0=1.0000E+05
INTEGER(NSPEC,NELEM);NSPEC=7;NELEM=4
INTEGER(NCSTEP,NCREAC)
MESG( Enter required combustion model
MESG( Default: 1 step finite rate EBU
MESG( The options are:
MESG( EBU1 - 1 step finite-rate EBU
MESG( EBU2 - 2 step 2 reactions finite-rate EBU
MESG( EBU3 - 2 step 3 reactions finite-rate EBU
READVDU(CMOD,CHAR,EBU1)
CASE :CMOD: OF
WHEN EBU1,4
+ MESG(1 step finite-rate EBU model
+ MESG(2CH4 + 4O2 > 2CO2 + 4H2O
+ NCSTEP=1;NCREAC=1
+ SCRS(SYSTEM,NCSTEP,NCREAC,NELEM,FRATE*)
+ SCRS(SPECIES,CH4,O2,H2,CO,H2O,CO2,N2)
+ SCRS(PROP,CHEMKIN,SCH4)
+ STORE(P1RS);ICOMB=0
WHEN EBU2,4
+ MESG(2 step 2 reactions finite-rate EBU model
+ MESG( 2CH4 + 3O2 > 2CO + 4H2O
+ MESG( 2CO + O2 > 2CO2
+ NCSTEP=2;NCREAC=2
+ SCRS(SYSTEM,NCSTEP,NCREAC,NELEM,FRATE*)
+ SCRS(SPECIES,CH4,O2,H2,CO,H2O,CO2,N2)
+ SCRS(PROP,CHEMKIN,STWO)
+ STORE(P1RS,S1RS);ICOMB=1
WHEN EBU3,4
+ MESG(2 step 3 reactions finite-rate EBU model
+ MESG(2CH4 + O2 > 2CO + 4H2
+ MESG(2CO + O2 > 2CO2
+ MESG(2H2 + O2 > 2H2O
+ NCSTEP=2;NCREAC=3
+ SCRS(SYSTEM,NCSTEP,NCREAC,NELEM,FRATE*)
+ SCRS(SPECIES,CH4,O2,H2,CO,H2O,CO2,N2)
+ SCRS(PROP,CHEMKIN,SCRS)
+ STORE(P1RS,S1RS,S2RS);ICOMB=2
ENDCASE
STORE(MMWT)
** Define fuel & oxidiser composition & temperature
SCRS(FUIN,YFUIN,YOXIN,0.0,0.0,0.0,0.0,YN2IN,TEMFU)
SCRS(OXIN,YFUIN,YOXIN,0.0,0.0,0.0,0.0,YN2IN,TEMOX)
*** END OF EXTENDED SCRS MODEL SETTINGS
GROUP 11. Initialization of variable or porosity fields
INIADD=F; FIINIT(W1)=WINO
KEINIT=(0.011*WINO)**2; FIINIT(EP)=0.1643*KEINIT**1.5/(0.01*RTUBE)
IF(THRAD) THEN
+ REAL(TGUESS);TGUESS=300.; FIINIT(SRAD)=0.07*SIGMA*TGUESS**4
ENDIF
IF(HSOLV) THEN
+ FIINIT(H1)=1.267E3
ENDIF
FIINIT(KE)=KEINIT; FIINIT(CH4)=0.85*YFUIN
GROUP 13. Boundary conditions and special sources
* INLET boundary condition for centre burner
KEL=0.5*(0.2*WINF)**2; EPL=1.643*((KEL)**1.5)/0.0095
INLET(SCRSF,LOW,1,NX,#2,#2,1,1,#1,#NREGT)
VALUE(SCRSF,P1,GRND1); VALUE(SCRSF,W1,WINF)
VALUE(SCRSF,EP,EPL); VALUE(SCRSF,KE,KEL)
VALUE(SCRSF,F,1.); VALUE(SCRSF,CH4,YFUIN)
IF(HSOLV) THEN
+ VALUE(SCRSF,H1,GRND3)
ENDIF
* INLET boundary condition for outer burner
KEL=0.5*(0.2*WINO)**2; EPL=1.643*((KEL)**1.5)/0.05
INLET(SCRSO,LOW,1,NX,#4,#4,1,1,#1,#NREGT)
VALUE(SCRSO,P1,GRND1); VALUE(SCRSO,W1,WINO)
VALUE(SCRSO,EP,EPL); VALUE(SCRSO,KE,KEL)
VALUE(SCRSO,F,0.); VALUE(SCRSO,CH4,YFUIN)
IF(HSOLV) THEN
+ VALUE(SCRSO,H1,GRND3)
ENDIF
PATCH(OUT,HIGH,1,NX,1,NY,#NREGZ,#NREGZ,#1,#NREGT)
COVAL(OUT,P1,1.E2,0.);COVAL(OUT,F,ONLYMS,SAME)
IF(HSOLV) THEN
+ COVAL(OUT,H1,ONLYMS,SAME)
ENDIF
* WALL boundary condition, name WALL3
PATCH(NWALL3,NWALL,1,NX,#NREGY,#NREGY,#2,NZ,#1,#NREGT)
COVAL(NWALL3,W1,GRND2,0.0);COVAL(NWALL3,KE,GRND2,GRND2)
COVAL(NWALL3,EP,GRND2,GRND2)
IF(THRAD) THEN
+ PATCH(NWALL3R,NORTH,1,NX,#NREGY,#NREGY,1,NZ,#1,#NREGT)
+ COVAL(NWALL3R,SRAD,EMISW/(2.0-EMISW),EMPW)
ENDIF
GROUP 15. Termination of sweeps
LSWEEP=200
GROUP 16. Termination of iterations
GROUP 17. Under-relaxation devices
RELAX(P1,LINRLX,1.0); RELAX(V1,FALSDT,5.E-3)
RELAX(W1,FALSDT,5.E-3); RELAX(KE,FALSDT,5.E-3)
RELAX(EP,FALSDT,5.E-3); RELAX(DEN1,LINRLX,0.5)
RELAX(F,LINRLX,0.8); RELAX(CH4,FALSDT,1.E-3)
IF(ICOMB.GT.0) THEN
+ RELAX(CO,FALSDT,1.E-3)
ENDIF
IF(ICOMB.EQ.2) THEN
+ RELAX(H2,FALSDT,1.E-3)
ENDIF
IF(HSOLV) THEN
+ RELAX(H1,FALSDT,1.0)
ENDIF
IF(THRAD) THEN
+ RELAX(SRAD,FALSDT,1.0)
ENDIF
GROUP 18. Limits on variables or increments to them
VARMIN(TMP1)=1.E-10; VARMIN(DEN1)=1.E-10
OUTPUT(TMP1,P,P,P,P,Y,Y); OUTPUT(DEN1,P,P,P,P,Y,Y)
GROUP 20. Preliminary print-out
ECHO=T
GROUP 21. Print-out of variables
GROUP 22. Spot-value print-out
IXMON=1;IYMON=NY/2;IZMON=6
GROUP 23. Field print-out and plot control
TSTSWP=-1;ITABL=3;NPLT=1
GROUP 24. Dumps for restarts