1 files changed, 112 insertions, 0 deletions
diff --git a/1328/CH7/EX7.4/7_4.sce b/1328/CH7/EX7.4/7_4.sce
new file mode 100644
index 000000000..046cd5410
--- /dev/null
+++ b/1328/CH7/EX7.4/7_4.sce
@@ -0,0 +1,112 @@
+printf("\t example 7.4 \n");
+printf("\t approximate values are mentioned in the book \n");
+T1=93; // inlet hot fluid,F
+T2=85; // outlet hot fluid,F
+t1=75; // inlet cold fluid,F
+t2=80; // outlet cold fluid,F
+W=175000; // lb/hr
+w=280000; // lb/hr
+printf("\t 1.for heat balance \n");
+printf("\t for distilled water \n");
+c=1; // Btu/(lb)*(F)
+Q=((W)*(c)*(T1-T2)); // Btu/hr
+printf("\t total heat required for distilled water is : %.1e Btu/hr \n",Q);
+printf("\t for raw water \n");
+c=1; // Btu/(lb)*(F)
+Q=((w)*(c)*(t2-t1)); // Btu/hr
+printf("\t total heat required for raw water is : %.1e 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 : %.2f \n",R);
+S=((t2-t1)/(T1-t1));
+printf("\t S is : %.3f \n",S);
+printf("\t FT is 0.945 \n"); // from fig 18
+delt=(0.945*LMTD); // F
+printf("\t delt is : %.2f 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)+(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 : %.1f F \n",tc);
+printf("\t hot fluid:shell side,distilled water \n");
+ID=15.25; // in
+C=0.1875; // clearance
+B=12; // baffle spacing,in
+PT=0.9375;
+as=((ID*C*B)/(144*PT)); // flow area,ft^2,using eq.7.1
+printf("\t flow area is : %.3f ft^2 \n",as);
+Gs=(W/as); // mass velocity,lb/(hr)*(ft^2),using eq.7.2
+printf("\t mass velocity is : %.1e lb/(hr)*(ft^2) \n",Gs);
+mu1=0.81*2.42; // at 89F,lb/(ft)*(hr), from fig.14
+De=0.55/12; // from fig.28,ft
+Res=((De)*(Gs)/mu1); // reynolds number
+printf("\t reynolds number is : %.2e \n",Res);
+jH=73; // from fig.28
+c=1; // Btu/(lb)*(F),at 89F,from fig.table 4
+k=0.36; // Btu/(hr)*(ft^2)*(F/ft), from table 4
+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)); // using eq.6.15,Btu/(hr)*(ft^2)*(F)
+printf("\t individual heat transfer coefficient is : %.2e Btu/(hr)*(ft^2)*(F) \n",ho);
+printf("\t cold fluid:inner tube side,raw water \n");
+Nt=160;
+n=2; // number of passes
+L=16; //ft
+at1=0.334; // 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 : %.3f ft^2 \n",at);
+Gt=(w/(at)); // mass velocity,lb/(hr)*(ft^2)
+printf("\t mass velocity is : %.3e lb/(hr)*(ft^2) \n",Gt);
+V=(Gt/(3600*62.5));
+printf("\t V is %.1f fps \n",V);
+mu2=0.92*2.42; // at 77.5F,lb/(ft)*(hr)
+D=0.65/12; //ft
+Ret=((D)*(Gt)/mu2); // reynolds number
+printf("\t reynolds number is : %.2e \n",Ret);
+hi=1350*0.99; //using fig.25,Btu/(hr)*(ft^2)*(F)
+ID=0.65; // 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 : %.0f Btu/(hr)*(ft^2)*(F) \n",Uc);
+printf("\t ·when both. film coefficients are high the thermal resistance of the tube metal is not necessarily insignificant as assumed in the derivation of Eq. (6.38). For a steel 1.8 BWG tube Rm= 0.00017 and for copper Rm= 0.000017 \n");
+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 : %.0f 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=0.0019; // friction factor for reynolds number 16200, using fig.29
+s=1; // for reynolds number 25300,using fig.6
+Ds=15.25/12; // ft
+phys=1;
+N=(12*L/B); // number of crosses,using eq.7.43
+printf("\t number of crosses are : %.0f \n",N);
+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 delPs is 10 psi \n");
+printf("\t pressure drop  for inner pipe \n");
+f=0.00019; // friction factor for reynolds number 36400, using fig.26
+s=1;
+phyt=1;
+D=0.054; // ft
+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=0.33; // 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