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May 25, 2009, 09:39 |
HELP----Surface Reaction UDF
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#1 |
New Member
Ashi
Join Date: May 2009
Posts: 1
Rep Power: 0 |
Hi to all,,
I am finding difficulty to define the "Surface Reaction" UDF for "Ethanol steam reforming reaction'. I have tried to define it on face but it doesn't work. Its is giving error. I request you to kindly help me regarding the same, so that I can proceed with my work further. Hope for your kind reply. #include "udf.h" #include "math.h" /* This function defines the volumetric rate of reaction mechanism*/ DEFINE_SR_RATE( rate,f,t,r,my,yi,rr) { /*Pre-exponential factors and Activation energies. The pre-exponential factors are multiplied by the density of the catalyst multiplied by the effectiveness factor final for Ethanol*/ #define A1 33*1400*.001 #define A2 297*1400*.001 #define A3 7.31e12*1400*.001 #define A4 2.10e10*1400*.001 #define E1 10.1e3 #define E2 21e3 #define E3 2e3 #define E4 13.9e3 /* Species numbers. Must match order in Fluent panel*/ #define CO 0 #define H2 1 #define C2H6O 2 #define H2O 3 #define CO2 4 #define N2 5 #define NUM_SPECS 6 /* Mol. Wt of Species */ #define MW_CO 28 #define MW_H2 2 #define MW_C2H6O 46 #define MW_H2O 18 #define MW_CO2 44 #define MW_N2 28 /*Heats of adsorption (J/kmol) #define HCO -70.65e3 #define HH2 -82.9e3 #define HC2H6O -38.28e3/*(same)*/ #define HH2O 88.68e3 /*Universal Gas Constant (J/mol*K) */ #define UGC 8.314 /*Adsorption pre-exponential constants */ #define ACO 8.23e-5 #define AH2 6.12e-9 #define AC2H6O 6.65e-4 #define AH2O 1.57e4 /*Adsorption coefficient final for ethanol*/ real KCO=ACO*exp(-HCO/(UGC*F_T(f,t))); real KH2=AH2*exp(-HH2/(UGC*F_T(f,t))); real KC2H6O=AC2H6O*exp(-HC2H6O/(UGC*F_T(f,t))); real KH2O=AH2O*exp(-HH2O/(UGC*F_T(f,t))); real KCO2=ACO2*exp(-HCO2/(UGC*F_T(f,t))); /*Mass fractions final for ethanol*/ real mC2H6O=F_YI(f,t,0); real mH2O=F_YI(f,t,1); real mCO2=F_YI(f,t,2); real mN2=F_YI(f,t,3); real mCO=F_YI(f,t,4); real mH2=F_YI(f,t,5); /*Partial pressures final for ethanol*/ real pOp=1.01; /*operating pressure (bar)*/ real sum=(mC2H6O/46+mH2O/18+mCO2/44+mN2/28+mCO/28+mH2/2); real pC2H6O=mC2H6O/46/sum*pOp; real pH2O=mH2O/18/sum*pOp; real pCO2=mCO2/44/sum*pOp; real pN2=mN2/28/sum*pOp; real pCO=mCO/28/sum*pOp; pH2=mH2/2/sum*pOp; /* Initialize equilibrium constants final for ethanol*/ real K1=2.33e+09; real K2=1.49e+4; real K3=3e+09; real K4=K3; if (!strcmp(r->name, "reaction-2")) {K2=1.49e+4; *rate=A2*exp(-E2/(8.314*(F_T(f,t))))*((pC2H60)-((pCO2*pCO2*pH2*pH2*pH2*pH2*pH2*pH2)/(K1*pH2O*pH2O*pH2O)))/(1+5*pC2H6O);} else if (!strcmp(r->name, "reaction-1")) {*rate=A1*exp(-E1/(8.314*(F_T(f,t))))*((pC2H6O)-((pCO2*pCO2*pH2*pH2*pH2*pH2*pH2*pH2)/(K1*pH2O*pH2O*pH2O)));} else if (!strcmp(r->name, "reaction-3")) {K3=3e+09; *rate=A3*exp(-E3/(8.314*(F_T(f,t))))*(((pC2H6O*pH2O*pH2O*pH2O)/(pCO2*pH2*pH2*pH2))-((pCO2*pH2*pH2*pH2)/K3))/((1+2e+16*pC2H6O+((3.3e+07*pC2H6O*pH2O*pH2O)/(pCO2*pH2*pH2*pH2)));} else if (!strcmp(r->name, "reaction-4")) {K4=3e+09; *rate=(A4*exp(-E4/(8.314*(F_T(f,t))))*(((pC2H6O*pH2O*pH2O*pH2O)/(pCO2*pH2*pH2*pH2))-((pCO2*pH2*pH2*pH2)/K4))/((1+2.73e+12*pC2H6O+((100000*pCO2*pH2*PH2*pH2)/pH2O))));} if (*rate>10) /* stops reaction rate from becoming unreasonable high; facilitates convergence */ {*rate=10;} else if (*rate<-10) {*rate=-10;} *rr=*rate; |
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May 19, 2020, 21:13 |
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#2 |
New Member
zaixing
Join Date: Apr 2020
Posts: 9
Rep Power: 6 |
Hello,friend.My doctoral project is aslo about Steam Reforming of ethanol by using CFD.
I also face the same problem. How did you solve it? |
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