printf("\t example 9.1 \n"); printf("\t approximate values are mentioned in the book \n"); T1=245; // inlet hot fluid,F T2=95; // outlet hot fluid,F t1=85; // inlet cold fluid,F t2=95; // outlet cold fluid,F W=9872; // lb/hr w=78500; // lb/hr printf("\t 1.for heat balance \n"); printf("\t for ammonia gas \n"); c=0.53; // Btu/(lb)*(F) Q=((W)*(c)*(T1-T2)); // Btu/hr printf("\t total heat required for ammonia gas 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 : %.2f 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 :%.1f F \n",LMTD); R=((T1-T2)/(t2-t1)); printf("\t R is : %.0f \n",R); S=((t2-t1)/(T1-t1)); printf("\t S is : %.4f \n",S); printf("\t FT is 0.837 \n"); // from fig 18 delt=(0.837*LMTD); // F printf("\t delt is : %.1f F \n",delt); Tc=((T2)+(T1))/2; // caloric temperature of hot fluid,F printf("\t caloric temperature of hot fluid is : %.0f F \n",Tc); tc=((t1)+(t2))/2; // caloric temperature of cold fluid,F printf("\t caloric temperature of cold fluid is : %.0f F \n",tc); printf("\t hot fluid:shell side,ammonia at 83psia \n"); ID=23.25; // in C=0.1875; // clearance B=12; // baffle spacing,in PT=0.937; as=((ID*C*B)/(144*PT)); // flow area,ft^2,from eq 7.1 printf("\t flow area is : %.3f 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=0.012*2.42; // at 170F,lb/(ft)*(hr), from fig.15 De=0.55/12; // from fig.28,ft Res=((De)*(Gs)/mu1); // reynolds number printf("\t reynolds number is : %.2e \n",Res); jH=118; // from fig.28 k=0.017; // Btu/(hr)*(ft^2)*(F/ft),from table 5 Z=0.97; // Z=(Pr*(1/3)) prandelt number ho=((jH)*(k/De)*(Z)*1); // using eq.6.15,Btu/(hr)*(ft^2)*(F) printf("\t individual heat transfer coefficient is : %.1f Btu/(hr)*(ft^2)*(F) \n",ho); printf("\t cold fluid:inner tube side,water \n"); Nt=364; n=8; // number of passes L=8; //ft at1=0.302; // flow area, in^2,from table 10 at=((Nt*at1)/(144*n)); // total area,ft^2,from eq.7.48 printf("\t flow area is : %.4f 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=0.82*2.42; // at 90F,lb/(ft)*(hr),from fig 14 D=(0.62/12); // ft,from table 10 Ret=((D)*(Gt)/mu2); // reynolds number printf("\t reynolds number is : %.2e \n",Ret); hi=900; // using fig 25,Btu/(hr)*(ft^2)*(F) printf("\t hi is : %.0f Btu/(hr)*(ft^2)*(F) \n",hi); ID=0.62; // ft OD=0.75; //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); 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=0.1963; // 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 : %.3f (hr)*(ft^2)*(F)/Btu \n",Rd); printf("\t pressure drop for annulus \n"); f=0.00162; // friction factor for reynolds number 40200, using fig.29 Ds=23.25/12; // ft phys=1; N=(12*L/B); // number of crosses,using eq.7.43 printf("\t number of crosses are : %.0f \n",N); rowgas=0.209; printf("\t rowgas is %.3f lb/ft^3 \n",rowgas); s=rowgas/62.5; printf("\t s is %.5f \n",s); delPs=((f*(Gs^2)*(Ds)*(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 2 psi \n"); printf("\t pressure drop for inner pipe \n"); f=0.000225; // friction factor for reynolds number 21400, using fig.26 s=1; D=0.0517; //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=0.090; // 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