我做了个比较大的程序 但是在其中一直有一个重复性的错误 是这样写的 undefined symbol ' ' in function main 请各位指导一下 这到底是什么意思 谢谢 是没有定义吗 还是没有用 程序如下 可以不怎么看 太多了 #define pai 3.14159265 #include <math.h>
double max(double x,double y) {double z; if(x>=y) z=x; else z=y; return z; }
double min(double x,double y) {double z; if(x>=y) z=y; else z=x; return z; }
double midu(double x,double y)/*求相对密度*//*x=1+Tm/100,y是相对密度 成功*/ {double z; z=0.942+0.248*x+0.174*y*y+0.0841/(x*x)-0.312*x/y-0.56*exp(-x);/*计算物质的相对密度*/ return z;}
double bire(double x,double y,double z)/*相对密度 温度 油品特性 成功*/ {double m; m=(0.7072+(0.00147-0.000551*x)*y-0.318*x)*(0.055*z+0.35); return m; } /*成功了*/
double redao(double x,double y)/*相对密度 温度 已经成功*/ {double z; z=0.1008*(1-0.00054*y)/x; return z; }
double niandu1(double t)/*温度*//*求渣油的粘度*/ { double a,b,z; double c=1500,d=120;/*运动粘度*/ int t1=50,t2=100; b=log((log(c+1.22))/(log(d+1.22)))/(log((t1+273)/(t2+273))); a=log(log(c+1.22))-b*log(t1+273);
z=exp(exp(a+b*log(t+273)))-1.22; return z; }
double niandu2(double t)/*温度*//*求原油的粘度*/ { double a,b,z; double c=90,d=13;/*运动粘度*/ int t1=50,t2=100; b=log((log(c+1.22))/(log(d+1.22)))/(log((t1+273)/(t2+273))); a=log(log(c+1.22))-b*log(t1+273);
z=exp(exp(a+b*log(t+273)))-1.22; return z; }
main() {double midu(double x,double y); double bire(double x,double y,double z); double redao(double x,double y); double niandu1(double t); double niandu2(double t);/*函数声明*/
double wh=68250, /* 渣油的质量流量 千克每立方米*/ th1=382, /*渣油的入口温度*/ wc=175000, /*原油的质量流量*/ tc1=275; A=130, /*传热面积*/ D=0.7, /*壳体直径*/ do=0.025, /*管外径*/ di=0.02, /*内径*/ L=6, /*管长*/ At=0.0438, /*管程通道截面积*/ As=0.0525, /*壳程通道截面积*/ Ri=0.0005, /*渣油侧的污垢热阻*/ Ro=0.0001, /*原油侧的污垢热阻*/ Dh20=0.919, Dc20=0.850, /*D20 20度时的油品相对密度*/ K1=12.5, /*渣油的油品特性*/ K2=12.5; /*原油的油品特性*/
double tc20,th20,C,cpc1,cph1,Tmc,Tmh,Xc,Xh, dT1,dT2,dTm,pcm,phm,cpcm,cphm,N1,N2, rd1,rd2,Q,N,Np,Si,u1,Qi,Ai,Rei,Pri,Nui, hi0,twi,Nwi,hi,twi1,Twi,Hi, u2,Qo,Ao,de,Reo,Pro,,Nuo,ho0,two,Nwo, ho,two1,Two,Ho,k,H,Cmin,Cmax,NUT,R,TT,e, tc2,th2,eh,fi,dph,fo,dpc;
int m,n; xuhuan: cpc1=bire(Dc20,tc1,K1); /*定压比热容的计算*/ cph1=bire(Dh20,th1,K2); C=(wc*cpc1)/(wh*cph1); tc20=300;/*先假定一个温度*/ th20=th1-C*(tc20-tc1);
Tmc=(tc1+tc20)/2;/*定性温度*/ Tmh=(th1+th20)/2;
printf("Tmc=f%,Tmh=f%,tc20=f%,th20=f%",Tmc,Tmh,tc20,th20);
Xc=1+Tmc/100; Xh=1+Tmh/100;
dT1=th1-th20; dT2=tc20-tc1; dTm=(dT1-dT2)/log(dT1/dT2);
/*计算在定性温度下的个物性参数*/
pcm=midu(Xc,Dc20);/*密度是计算*/ phm=midu(Xh,Dh20);/*密度是计算*/ cpcm=bire(Dc20,Tmc,K1);/*定压比热容的计算*/ cphm=bire(Dh20,Tmh,K2); N1=niandu1(Tmh); N2=niandu2(Tmc); rd1=redao(Dh20,Tmh); rd2=redao(Dc20,Tmc); printf("pcm=%f,phm=f%,cpcm=f%,cphm=f%\n,N1=f%,N2=f%,rd1=f%,rd2=f%\n",pcm,phm,cpcm,cphm,N1,N2,rd1,rd2);/*所有的物性参数*/
/*管内表面传热系数的计算*/
int n; N=(int)(A/(pai*do*L))+1;/*管子的数量 ？？？？用不用/2*/ Np=2;/*管程的数量*/
Si=pai*di*di*N/(Np*4); u1=wh/(phm*Si); Qi=wh*cphm*(th1-th20); Ai=pai*di*L*N;/*面积的计算应该怎么样？？？？？*/
Rei=(di*u1*phm)/N1; Pri=(cphm*N1)/rd1; Nui=0.023*pow(Rei,0.8)*pow(Pri,0.33); hi0=Nui*rd1/di;
twi=Tmh-Qi/(hi0*Ai);/*壁温的设计*/ Nwi=niandu1(twi); hi=hi0*pow((N1/Nwi),0.14); twi1=Tmh-Qi/(hi*Ai);
for(n=0;fabs(twi-twi1)>=0.5;n++) {twi=twi1; Nwi=niandu1(twi); hi=hi0*pow((N1/Nwi),0.14); twi1=Tmh-Q/(hi*Ai); }; Twi=twi; Hi=hi; printf("Twi=f%,Hi=f%\n",Twi,Hi); printf("n=%d",n);
/*管外表面传热系数的计算*/
u2=wc/(As*pcm); Qo=wc*cpcm*(tc20-tc1); Ao=pai*do*L*N; de=4*As/(N*pai*do);/*用面积当量法求当量直径*/ Reo=(de*u2*pcm)/N2; Pro=(cpcm*N2)/rd2; Nuo=0.36*pow(Reo,0.55)*pow(Pro,0.333); ho0=Nuo*rd2/de;
two=Tmc-Qo/(ho*Ao); Nwo=niandu(two); ho=ho0*pow((N2/Nwo),0.14); two1=Tmc-Qo/(ho*Ao);
for(m=0;fabs(two-two1)>=0.5;m++) {two=two1; Nwo=niandu2(two); ho=ho0*pow((N2/Nwo),0.14); two1=Tmc-Qo/(ho*Ao); }; Two=two; Ho=hio; printf("Two=f%,Ho=f%\n",Two,Ho); printf("m=%d",m);
/*求综合传热系数*/ k=(1/Hi+Ri)*Ao/Ai+1/Ho+Ro; H=1/k; printf("H=f%\n",H);
/**/ Cmin=min((wh*cphm),(wc*cpcm)); Cmax=max((wh*cphm),(wc*cpcm)); NTU=H*A/Cmin; R=Cmin/Cmax;
TT=NTU*sqrt(1+R*R); e=2/((1+R)+sqrt(1+R)*(1+exp(-TT))/(1-exp(TT)); tc2=tc1+e*(th1-tc1); th2=th1-(wc*cpcm)*(tc2-tc1)/(wh*cphm);
if(fabs(tc2-tc20)>=0.1) {tc20=(tc2+tc20)/2; goto xuhuan; }; else {printf("The answer is:\n"); printf("tc2=f%,th2=f%,H=f%",tc2,th2,H); };
/*换热效率和热阻的计算*/ eh=(th1-th2)/(th1-tc1);/*换热是效率*/ if(Rei<100000) fi=0.4513*pow(Rei,-0.2663); else fi=0.2864*pow(Rei,-0.2258); dph=(fi*L/di+8)*wh*2*1.5/(2*1000*phm);
if(Reo<150) fo=120*pow(Reo,-0.993); else{ if(Reo>1500) fo=0.7664*pow(Reo,-0.0854); else fo=10*(15.312/(pow(log(Reo),4.735))-0.44); } dpc=(D*(19+1)*fi*0.15/de+10)*wc/(2*1000*pcm);
printf("eh=f%,dph=f%,dpc=f%\n",eh,dph,dpc);
}
