Page 185 - Fundamentals of Enhanced Oil and Gas Recovery

173
Thermal Recovery Processes

c. Estimate h nc (cont’d)
C an μ ð0:245Þð0:069Þ
N Pr 5 an 5 5 0:66
k ha 0:0255
r ci 2r to Þ gβρ 2
3
ð ð T to 2 T ci Þ
N Gr 5 an
μ an 2
3 8 24 2
ð
ð 0:35520:146Þ ð4:17 3 10 Þð9:75 3 10 Þð0:0388Þ 600 2 530Þ
5
2
ð0:069Þ
5 8:26 3 10 4
k hc 0:333 0:074
5 0:049 N Gr N Pr Þ N Pr
ð
k ha
4 0:333 0:074
5 0:049 8:26 3 10 3 0:66 ð0:66Þ 5 1:81

k hc 5 k ha 3 1.81 5 0.046 (Btu/h ft F)
d. Estimate h nc (cont’d)

k hc ð0:046Þ
h nc 5 5
r to ln r ci =r to ð0:146Þln 0:355=0:146

5 0:36 Btu=ðhft 2 FÞ
6. Calculate U to
21
ð
U to 5 1 1 r to ln r hd =r coÞ
ð h nc 1h r Þ k hcem
21

ð
5 1 1 ð0:146Þln 0:5=0:4Þ
ð 0:3616:39Þ 0:2
2

5 3:22 Btu=ðhft F Þ
2
7. Checking for U to tolerance, we started with U old 5 4:05 (Btu/h ft F), U new 5 3:22
to to
If this tolerance is not acceptable, go back to Slide No. 10 using
U to 5 U new
to
Estimate Calculated
Trial U to T h ( F) T ci ( F) h r h nc U to

1 4.05 395 530 6.39 0.36 3.22
2 3.22 367 487 6.00 0.42 3.15
3 3.15 364 485 5.97 0.42 3.14