FIG. 3 STRESS AMPLITUDE HISTORY
Te
mp
er
atu
re,
˚C
50
45
40
35
30
25
20
15
10
5
0
Time, hr
0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000
FIG. 4 TEMPERATURE GRADIENT, NORMAL CONDITIONS
Temperature, °C.
48.00
44. 23
42. 46
40. 69
38. 92
37. 15
35. 38
33. 61
31. 84
30.07
28. 30
26. 53
24. 76
22.99
21. 22
FIG. 5 GASOLINE TEMPERATURE, ERRODED CONDITIONS
Te
m
pe
rat
ur
e,˚
C
60
50
40
30
20
10
0
Time, hr
0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000
parent solid or fluid or another radiation absorptive solid, or the refraction
index. The radiation spectrum consists
of many bands and users specify their
edges. We considered the characteristics of radiation materials, sources, and
surfaces within every band, taking into
account the appropriate heat fluxes in
partial cells for solid cells inside the
semi-transparent solid bodies or immersed fluid-solid boundaries.
Heat transfer
Heat transfer in solids and fluids with
energy exchanged between them (
conjugate heat transfer) is important in
using any CFD software. Equation 2
(Navier-Stokes) describes heat transfer in fluids and Equation 3 heat flux.
Equation 4 describes heat conduction
in solid media.
Procedure
Three-dimensional modeling the
floating-roof tank via CFD analysis
uses multiple inputs from the field
tank:
• External analysis.
• Solid heat conduction.
• Solar radiation.
• Location: Cairo, July 31, 12 pm.
• Solid absorption.
• Time duration, 1 hr ( 3,600 sec).
• Media; gasoline, air.
• Wall material, condition.
Creating a fluid and solid mesh for
CFD analysis follows input of these
data (Table 2).
CFD analysis
A decrease in deck plate thickness to
5 mm from 8 mm due to surface corrosion increased surface temperature
of the stored gasoline to 54 °C. (129
°F.) from 45. 6 °C. (Figs. 3-6). Gasoline
vaporization totaled 7% in normal
conditions ( 45. 6 °C.) and 10% in corrosion conditions ( 54 °C.), an environmentally and economically problematic level for the operator. An internal
floating roof would reduce evaporation and increase safety.
