关于matlab

这使我编得一个程序，运行后，第12行出错，提示为"divide by zero";我找不到错误，麻烦高手看一下，我愿贡献所有分。程序如下；function Th2=abc(Dh,Dc,Cph,Cpc,Yh,Yc,Vh,Vc,Tm)Wh=68520,Wc=175000,Th1=382.0,Tc1=275.0,A=130;Th2o=input('number:')Th2=Th2o+1;while Th2-Th2o>0.1Th2o=Th2;Tc2=((Th1-Th2o)+Tc1);Tmc=(Tc1+Tc2)/2;Tmh=(Th1+Th2o)/2;T1=Th2o-Tc1;T2=Th1-Tc2;Tm=(T1-T2)/log(T1/T2);Xc=1+Tmc/100;Xh=1+Tmh/100;D20h=0.919;D20c=0.850;K=12.5;Dh=0.942+0.248*Xh+0.174*(D20h^2)+0.0841/(Xh*D20h)-(0.32*Xh)/D20h-0.556*exp(-Xh);Dc=0.942+0.248*Xc+0.174*(D20c^2)+0.0841/(Xc*D20c)-(0.32*Xc)/D20c-0.556*exp(-Xc);Cph=(0.7072+(0.001417-0.000551*D20h)*Tmh-0.318*D20h)*(0.055*K+0.35);Cpc=(0.7072+(0.001417-0.000551*D20c)*Tmc-0.318*D20c)*(0.055*K+0.35);Yh=(0.1008*(1-0.00054*Tmh))/D20h;Yc=(0.1008*(1-0.00054*Tmc))/D20c;t1=50;t2=100;V1h=1500;V1c=90;V2h=120;V2c=13;bh=log(log(V1h+1.22)/log(V2h+1.22))/log((t1+273)/(t2+273));ah=log(log(V1h+1.22))-bh*log(t1+273);bc=log(log(V1c+1.22)/log(V2c+1.22))/log((t1+273)/(t2+273));ac=log(log(V1c+1.22))-bc*log(t1+273);Vh=exp(exp(ah+bh*log(Tmh+273)))-1.22;Vc=exp(exp(ac+bc*log(Tmc+273)))-1.22;uh=(10*Dh*Vh)/102;uc=(10*Dc*Vc)/102;Q=Wc*Cpc*(Tc2-Tc1);K1=Q/(A*Tm);N=89;Np=2;di=0.02;Ai=33.55;S=(pi*di*di*N)/(4*Np);u=Wh/(Dh*S);Re=(di*u*Dh)/uh;Pr=(Cph*uh)/Yh;Hi0=(0.023*Re^0.8*Pr^0.33*Yh)/di;Tw0=Tmh+Q/(Hi0*Ai);Tw=Tw0+1;while Tw-Tw0>0.5Tw0=Tw;b=log(log(V1h+1.22)/log(V2h+1.22))/log((t1+273)/(t2+273));a=log(log(V1h+1.22))-b*log(t1+273);Vw=exp(exp(a+b*log(Tw0+273)))-1.22;Xw=1+Tw0/100;D20=0.919;Dw=0.942+0.248*Xw+0.174*(D20^2)+0.0841/(Xw*D20)-(0.32*Xw)/D20-0.556*exp(-Xw);uw=(10*Vw*Dw)/102;Hi=Hi0*(uh/uw)^0.14;Hi0=Hi;Tw=Tmh+Q/(Hi0*Ai);endARo=41.94;ARi=33.55;Ro=0.0005;Ri=0.0001;Ho=(1/K1-Ro)-((1/Hi+Ri)*ARo)/ARi;if Wh*Cph<Wc*Cpc Cmin=Wc*Cpc; Cmax=Wh*Cph;else Cmin=Wh*Cph; Cmax=Wc*Cpc;endC=(Wc*Cpc)/(Wh*Cph);NTU=(K1*A)/Cmin;L=NTU*(1+(Cmin/Cmax)^2)^0.5;E=2/((1+(Cmin/Cmax))+((1+(Cmin/Cmax)^0.5)*(1+exp(-L))));Th2=Th1-E*(Th1-Tc1);Tc2=Tc1+(Tc2-Tc1)/C;enddisp(Th2)disp(Tc2)