printf("\t example 8.1 \n"); printf("\t approximate values are mentioned in the book \n"); T1=358; // inlet hot fluid,F T2=100; // outlet hot fluid,F t1=90; // inlet cold fluid,F t2=120; // outlet cold fluid,F W=49600; // lb/hr w=233000; // lb/hr printf("\t 1.for heat balance \n"); printf("\t for oil \n"); c=0.545; // Btu/(lb)*(F) Q=((W)*(c)*(T1-T2)); // Btu/hr printf("\t total heat required for oil is : %.2e Btu/hr \n",Q); printf("\t for water \n"); c=1; // Btu/(lb)*(F) Q=((w)*(c)*(t2-t1)); // Btu/hr printf("\t total heat required for water is : %.2e Btu/hr \n",Q); 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 :%.0f F \n",LMTD); R=((T1-T2)/(t2-t1)); printf("\t R is : %.1f \n",R); S=((t2-t1)/(T1-t1)); printf("\t S is : %.3f \n",S); printf("\t FT is 0.93 \n"); // from fig 19 for 2-4 exchanger delt=(0.93*LMTD); // F printf("\t delt is : %.1f F \n",delt); X=((delt1)/(delt2)); printf("\t ratio of two local temperature difference is : %.3f \n",X); Fc=0.25; // from fig.17 Kc=0.47; // 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,oil \n"); ID=35; // in C=0.25; // clearance B=7; // baffle spacing,in PT=1.25; as=((ID*C*B)/(144*PT))/2; // flow area,ft^2,from eq 7.1 printf("\t flow area is : %.2f ft^2 \n",as); Gs=(W/as); // mass velocity,lb/(hr)*(ft^2),from eq 7.2 printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gs); mu1=1.12*2.42; // at 165F,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 : %.1e \n",Res); jH=52.5; // from fig.28 Z=0.2; // Z=(k)*(Pr*(1/3)) prandelt number Ho=((jH)*(1/De)*(Z)); // H0=(h0/phys),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,water \n"); Nt=454; n=6; // number of passes L=12; //ft at1=0.455; // 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); V=(Gt/(3600*62.5)); // fps printf("\t V is : %.2f fps \n",V); mu2=0.73*2.42; // at 98F,lb/(ft)*(hr),from fig 14 D=(0.76/12); // ft,from table 10 Ret=((D)*(Gt)/mu2); // reynolds number printf("\t reynolds number is : %.2e \n",Ret); hi=1010*0.96; // using fig 25,Btu/(hr)*(ft^2)*(F) printf("\t hi is : %.0f Btu/(hr)*(ft^2)*(F) \n",hi); ID=0.76; // ft OD=1; //ft hio=((hi)*(ID/OD)); // using eq.6.5 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=1.95*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 : %.0f 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); Q=6980000; // taking rounded value,Btu/hr 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 : %.4f (hr)*(ft^2)*(F)/Btu \n",Rd); printf("\t pressure drop for annulus \n"); f=0.00215; // friction factor for reynolds number 8900, using fig.29 s=0.82; // for reynolds number 25300,using fig.6 Ds=35/12; // 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)*(2*N))/(5.22*(10^10)*(De)*(s)*(phys))); // using eq.7.44,psi printf("\t delPs is : %.0f psi \n",delPs); printf("\t allowable delPs is 10 psi \n"); printf("\t pressure drop for inner pipe \n"); f=0.000195; // friction factor for reynolds number 34900, using fig.26 s=1; D=0.0633; //ft phyt=1; 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=0.13; // 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 delPT is 10 psi \n"); //end