printf("\t example 7.3 \n"); printf("\t approximate values are mentioned in the book \n"); T1=390; // inlet hot fluid,F T2=200; // outlet hot fluid,F t1=100; // inlet cold fluid,F t2=170; // outlet cold fluid,F W=43800; // lb/hr w=149000; // lb/hr printf("\t 1.for heat balance \n"); printf("\t for kerosene \n"); c=0.605; // Btu/(lb)*(F) Q1=((W)*(c)*(T1-T2)); // Btu/hr printf("\t total heat required for kerosene is : %.1e Btu/hr \n",Q1); // calculation mistake in problem printf("\t for crude oil \n"); c=0.49; // Btu/(lb)*(F) Q=((w)*(c)*(t2-t1)); // Btu/hr printf("\t total heat required for mid continent crude is : %.1e Btu/hr \n",Q); // calculation mistake in problem delt1=T2-t1; //F delt2=T1-t2; // F printf("\t delt1 is : %.0f F \n",delt1); printf("\t delt2 is : %.0f F \n",delt2); LMTD=((delt2-delt1)/((2.3)*(log10(delt2/delt1)))); printf("\t LMTD is :%.1f F \n",LMTD); R=((T1-T2)/(t2-t1)); printf("\t R is : %.2f \n",R); S=((t2-t1)/(T1-t1)); printf("\t S is : %.3f \n",S); printf("\t FT is 0.905 \n"); // from fig 18 delt=(0.905*LMTD); // F printf("\t delt is : %.0f F \n",delt); X=((delt1)/(delt2)); printf("\t ratio of two local temperature difference is : %.3f \n",X); Fc=0.42; // from fig.17 Kc=0.20; // crude oil controlling Tc=((T2)+((Fc)*(T1-T2))); // caloric temperature of hot fluid,F printf("\t caloric temperature of hot fluid is : %.0f F \n",Tc); tc=((t1)+((Fc)*(t2-t1))); // caloric temperature of cold fluid,F printf("\t caloric temperature of cold fluid is : %.0f F \n",tc); printf("\t hot fluid:shell side,kerosene \n"); ID=21.25; // in C=0.25; // clearance B=5; // baffle spacing,in PT=1.25; as=((ID*C*B)/(144*PT)); // flow area,ft^2 printf("\t flow area is : %.4f ft^2 \n",as); Gs=(W/as); // mass velocity,lb/(hr)*(ft^2) printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gs); mu1=0.40*2.42; // at 280F,lb/(ft)*(hr), from fig.14 De=0.99/12; // from fig.28,ft Res=((De)*(Gs)/mu1); // reynolds number printf("\t reynolds number is : %.2e \n",Res); jH=93; // from fig.28 c=0.59; // Btu/(lb)*(F),at 280F,from fig.4 k=0.0765; // Btu/(hr)*(ft^2)*(F/ft), from fig.1 Pr=((c)*(mu1)/k)^(1/3); // prandelt number raised to power 1/3 printf("\t Pr is : %.3f \n",Pr); Ho=((jH)*(k/De)*(Pr)); // H0=(h0/phya),using eq.6.15,Btu/(hr)*(ft^2)*(F) printf("\t individual heat transfer coefficient is : %.0f Btu/(hr)*(ft^2)*(F) \n",Ho); printf("\t cold fluid:inner tube side,crude oil \n"); D=0.0675; // ft Nt=158; n=4; // number of passes L=16; //ft at1=0.515; // flow area, in^2 at=((Nt*at1)/(144*n)); // total area,ft^2,from eq.7.48 printf("\t flow area is : %.3f ft^2 \n",at); Gt=(w/(at)); // mass velocity,lb/(hr)*(ft^2) printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gt); mu2=3.6*2.42; // at 129F,lb/(ft)*(hr) Ret=((D)*(Gt)/mu2); // reynolds number printf("\t reynolds number is : %.2e \n",Ret); jH=31; // from fig.24 c=0.49; // Btu/(lb)*(F),at 304F,from fig.4 k=0.077; // Btu/(hr)*(ft^2)*(F/ft), from fig.1 Pr=((c)*(mu2)/k)^(1/3); // prandelt number raised to power 1/3 printf("\t Pr is : %.3f \n",Pr); Hi=((jH)*(k/D)*(Pr)*(1^0.14)); //Hi=(hi/phyp),using eq.6.15a,Btu/(hr)*(ft^2)*(F) printf("\t Hi is : %.0f Btu/(hr)*(ft^2)*(F) \n",Hi); ID=0.81; // ft OD=1; //ft Hio=((Hi)*(ID/OD)); //Hio=(hio/phyp), using eq.6.5 printf("\t Correct Hi0 to the surface at the OD is : %.0f Btu/(hr)*(ft^2)*(F) \n",Hio); muw=1.5*2.42; // lb/(ft)*(hr), from fig.14 phyt=(mu2/muw)^0.14; printf("\t phyt is : %.2f \n",phyt); // from fig.24 hio=(Hio)*(phyt); // from eq.6.37 printf("\t Correct hi0 to the surface at the OD is : %.0f Btu/(hr)*(ft^2)*(F) \n",hio); tw=(tc)+(((Ho)/(Hio+Ho))*(Tc-tc)); // from eq.5.31 printf("\t tw is : %.0f F \n",tw); muw=0.56*2.42; // lb/(ft)*(hr), from fig.14 phys=(mu1/muw)^0.14; printf("\t phys is : %.2f \n",phys); // from fig.24 ho=(Ho)*(phys); // from eq.6.36 printf("\t Correct h0 to the surface at the OD is : %.0f Btu/(hr)*(ft^2)*(F) \n",ho); Uc=((hio)*(ho)/(hio+ho)); // clean overall coefficient,Btu/(hr)*(ft^2)*(F) printf("\t clean overall coefficient is : %.1f Btu/(hr)*(ft^2)*(F) \n",Uc); A2=0.2618; // actual surface supplied for each tube,ft^2,from table 10 A=(Nt*L*A2); // ft^2 printf("\t total surface area is : %.0f ft^2 \n",A); UD=((Q)/((A)*(delt))); printf("\t actual design overall coefficient is : %.1f Btu/(hr)*(ft^2)*(F) \n",UD); Rd=((Uc-UD)/((UD)*(Uc))); // (hr)*(ft^2)*(F)/Btu printf("\t actual Rd is : %.5f (hr)*(ft^2)*(F)/Btu \n",Rd); printf("\t pressure drop for annulus \n"); f=0.00175; // friction factor for reynolds number 25300, using fig.29 s=0.73; // for reynolds number 25300,using fig.6 Ds=21.25/12; // ft N=(12*L/B); // number of crosses,using eq.7.43 printf("\t number of crosses are : %.0f \n",N); delPs=((f*(Gs^2)*(Ds)*(N))/(5.22*(10^10)*(De)*(s)*(phys))); // using eq.7.44,psi printf("\t delPs is : %.1f psi \n",delPs); printf("\t allowable delPa is 10 psi \n"); printf("\t pressure drop for inner pipe \n"); f=0.000285; // friction factor for reynolds number 8220, using fig.26 s=0.83; delPt=((f*(Gt^2)*(L)*(n))/(5.22*(10^10)*(D)*(s)*(phyt))); // using eq.7.45,psi printf("\t delPt is : %.1f psi \n",delPt); X1=0.15; // X1=((V^2)/(2*g)), for Gt 1060000,using fig.27 delPr=((4*n*X1)/(s)); // using eq.7.46,psi printf("\t delPr is : %.1f psi \n",delPr); delPT=delPt+delPr; // using eq.7.47,psi printf("\t delPT is : %.1f psi \n",delPT); printf("\t allowable delPs is 10 psi \n"); //end