1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
printf("\t example 7.6 \n");
printf("\t approximate values are mentioned in the book \n");
T1=150; // inlet hot fluid,F
T2=90; // outlet hot fluid,F
t1=68; // inlet cold fluid,F
t2=90; // outlet cold fluid,F
W=20160; // lb/hr
w=41600; // lb/hr
printf("\t 1.for heat balance \n");
printf("\t for solution \n");
c=(0.3*0.19)+(0.7*1); // Btu/(lb)*(F), bcoz of 30 percent of solution
Q1=((W)*(c)*(T1-T2)); // Btu/hr
printf("\t total heat required for solution is : %.2e Btu/hr \n",Q1);
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 :%.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 0.81 \n"); // from fig 18
delt=(0.81*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 : %.1f F \n",tc);
printf("\t hot fluid:shell side,phosphate solution \n");
ID=10.02; // in
C=0.25; // clearance
B=2; // baffle spacing,in
PT=1;
as=((ID*C*B)/(144*PT)); // flow area,ft^2,using eq.7.1
printf("\t flow area is : %.4f ft^2 \n",as);
Gs=(W/as); // mass velocity,lb/(hr)*(ft^2),using eq.7.2
printf("\t mass velocity is : %.2e lb/(hr)*(ft^2) \n",Gs);
mu1=1.20*2.42; // at 120F,lb/(ft)*(hr), from fig.14
De=0.95/12; // from fig.28,ft
Res=((De)*(Gs)/mu1); // reynolds number
printf("\t reynolds number is : %.3e \n",Res);
jH=71; // from fig.28
c=1; // Btu/(lb)*(F),at 120F,from fig.table 4
k=0.33; // Btu/(hr)*(ft^2)*(F/ft), from table 4
Pr=((0.757)*(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 : %.0f Btu/(hr)*(ft^2)*(F) \n",ho);
printf("\t cold fluid:inner tube side,raw water \n");
Nt=52;
n=2; // number of passes
L=16; //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));
printf("\t V is %.1f fps \n",V);
mu2=0.91*2.42; // at 79F,lb/(ft)*(hr),from table 14
D=(0.62/12); // from table 10
Ret=((D)*(Gt)/mu2); // reynolds number
printf("\t reynolds number is : %.2e \n",Ret);
hi=800*1; //using fig.25,Btu/(hr)*(ft^2)*(F)
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 : %.0f 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 : %.0f 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=0.0019; // friction factor for reynolds number 15750, using fig.29
s=1.3; // for reynolds number 25300,using fig.6
Ds=10.02/12; // 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=0.00023; // friction factor for reynolds number 17900, using fig.26
s=1;
phyt=1;
D=0.0517; // 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=0.08; // 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
|
