From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 3516/CH15/EX15.5/Ex15_5.sce | 116 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 3516/CH15/EX15.5/Ex15_5.sce (limited to '3516/CH15/EX15.5/Ex15_5.sce') diff --git a/3516/CH15/EX15.5/Ex15_5.sce b/3516/CH15/EX15.5/Ex15_5.sce new file mode 100644 index 000000000..9607778b2 --- /dev/null +++ b/3516/CH15/EX15.5/Ex15_5.sce @@ -0,0 +1,116 @@ +printf("\t example 15.5\n"); +printf("\t approximate values are mentioned in the book \n"); +W=40800; // lb/hr +w=4570; // lb/hr +printf("\t 1.for heat balance \n"); +Ht1=241; // enthalpy of liquid at 228F, Btu/lb, fig 9 +Ht2=338; // enthalpy of vapourat 228F, Btu/lb, fig 9 +Q=(W*(Ht2-Ht1)); +printf("\t total heat required for butane is : %.2e Btu/hr \n",Q); +l=868; // Btu/(lb), table 7 +Q=((w)*(l)); // Btu/hr +printf("\t total heat required for steam is : %.2e Btu/hr \n",Q); +delt=125; // delt=LMTD, isothermal boiling, eq 5.14 +// Tc and tc: Both streams are isuthermal +printf("\t trail 1 \n"); +A1=((Q)/((12000))); // Q/A1 =12000, first trial should always be taken for the maximum allowable flux +printf("\t A1 is : %.1e ft^2 \n",A1); +a1=0.1963; // ft^2/lin ft +L=16; +N1=(A1/(L*a1)); // table 10 +printf("\t number of tubes are : %.0f \n",N1); +N2=109; // assuming one tube passes, 13.25-in ID, from table 9 +A2=(N2*L*a1); // ft^2 +printf("\t total surface area is : %.0f ft^2 \n",A2); +UD=((Q)/((A2)*(delt))); +printf("\t correct design overall coefficient is : %.1f Btu/(hr)*(ft^2)*(F) \n",UD); +// Assume 4: 1 recirculation ratio +rowv=(58/(359*(688/492)*(14.7/290))); // eq 15.18 +printf("\t vapour density : %.2f lb/ft^3 \n",rowv); +Vv=0.44; +Vl=0.0372; // fig 6 +W1=4*W; +printf("\t weight flow of recirculated liquid : %.3e lb/hr \n",W1); +VL=W1*Vl; +VV=W*Vv; +printf("\t volume of liquid : %.2e ft^3 \n",VL); +printf("\t volume of vapour : %.3e ft^3 \n",VV); +V=VL+VV; +printf("\t total volume out of reboiler : %.3e ft^3 \n",V); +vo=(V/(W1+W)); +printf("\t vo is : %.4f ft^3/lb \n",vo); +Pl=((2.3*16)/(144*(vo-Vl)))*(log10(vo/Vl)); +printf("\t pressure leg : %.1f psi \n",Pl); +printf("\t frictional resistance \n"); +Nt=109; +n=1; // number of passes +at1=0.302; // flow area,table 10, 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=((W1+W)/(at)); // mass velocity,lb/(hr)*(ft^2) +printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gt); +mu1=0.242; // at 228F, fig 14,lb/(ft)*(hr) +D=0.0517; // ft +Ret=((D)*(Gt)/mu1); // reynolds number +printf("\t reynolds number is : %.1e \n",Ret); +f=0.000127; // using fig.26 +s=0.285; +phyt=1; +delPt=((f*(Gt^2)*(L)*(n))/(5.22*(10^10)*(D)*(s)*(phyt))); // using eq.7.45,psi +printf("\t delPt is : %.2f psi \n",delPt); +P=Pl+delPt; +printf("\t total resisitance : %.2f psi \n",P); +F=(16*0.43*62.5/144); +printf("\t driving force : %.2f psi \n",F); +// The resistances are greater than the hydrostatic head can provide; hence the recirculation ratio will be less than 4: 1 +printf("\t trial 2 \n"); // Assume 12'0" tubes and 4:1 recirculation ratio +A1=((Q)/((12000))); // Q/A1 =12000, first trial should always be taken for the maximum allowable flux +printf("\t A1 is : %.1e ft^2 \n",A1); +a1=0.1963; // ft^2/lin ft +L=12; +N1=(A1/(L*a1)); // table 10 +printf("\t number of tubes are : %.0f \n",N1); +N2=151; // assuming one tube passes, 15.25-in ID, from table 9 +A2=(N2*L*a1); // ft^2 +printf("\t total surface area is : %.0f ft^2 \n",A2); +UD=((Q)/((A2)*(delt))); +printf("\t correct design overall coefficient is : %.0f Btu/(hr)*(ft^2)*(F) \n",UD); +Pl=((2.3*12)/(144*(vo-Vl)))*(log10(vo/Vl)); +printf("\t pressure leg : %.1f psi \n",Pl); +printf("\t frictional resistance \n"); +Nt=151; +n=1; // number of passes +at1=0.302; // flow area,table 10, 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=((W1+W)/(at)); // mass velocity,lb/(hr)*(ft^2) +printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gt); +mu1=0.242; // at 228F, fig 14,lb/(ft)*(hr) +D=0.0517; // ft +Ret=((D)*(Gt)/mu1); // reynolds number +printf("\t reynolds number is : %.2e \n",Ret); +f=0.000135; // using fig.26 +s=0.285; +phyt=1; +delPt=((f*(Gt^2)*(12)*(n))/(5.22*(10^10)*(D)*(s)*(phyt))); // using eq.7.45,psi +printf("\t delPt is : %.2f psi \n",delPt); +P=Pl+delPt; +printf("\t total resisitance : %.2f psi \n",P); +F=(12*0.43*62.5/144); +printf("\t driving force : %.2f psi \n",F); +// Since the driving force is slightly greater than the resistances, a recirculation ratio better than 4:1 is assured. +printf("\t hot fluid : shell side,steam \n"); +ho=1500; // condensing steam +printf("\t cold fluid:inner tube side, butane \n"); +jH=330; // from fig.24 +Z=0.115; // Z=k*((c)*(mu1)/k)^(1/3), fig 16 +Hi=((jH)*(1/D)*(Z)); //, Hi=(hi/phyt)using eq.6.15d,Btu/(hr)*(ft^2)*(F) +printf("\t individual heat transfer coefficient is : %.0f Btu/(hr)*(ft^2)*(F) \n",Hi); +Hio=((300)*(0.62/0.75)); //Hio=(hio/phyp), using eq.6.9 +printf("\t Correct Hio 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 : %.0f Btu/(hr)*(ft^2)*(F) \n",Uc); +UD=89; +Rd=((Uc-UD)/((UD)*(Uc))); // (hr)*(ft^2)*(F)/Btu +printf("\t actual Rd is : %.4f (hr)*(ft^2)*(F)/Btu \n",Rd); +// end -- cgit