Vaporization of JP-8 Jet Fuel in a Simulated Aircraft Fuel Tank ...

Temperature, Deg. F.
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Thermocouple
Error
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Time, seconds
FID Error
Liquid Temp
Measured THC
Calculated THC, 115 FP
Calculated THC, 120 FP
Figure 5.12. Fuel heating at 30,000’ altitude, 4.6 psia; input fuel temperature and comparison of
calculated and measured ullage vapor concentrations, M.L.=31.5kg/m 3 .
5.3 JP-8 Tests with Simulated Flight Conditions
As mentioned earlier, simulated flight conditions consisted of one hour of ground time
with fuel tank heating from the bottom surface, an ascent at 1,000 feet per minute to the
desired cruising altitude (10,000’, figure 5.12, 20,000’, figure 5.14, 30,000’, figure 5.16),
cruise at this altitude for one hour, descent at –1,000 feet per minute to sea level, and
finally several minutes at ground level. Ambient temperature profiles were based on
weather data from Unisys constant height temperature plots of the United States.
Although the conditions used in this part of the experimentation were not identical to the
exact fuel tank conditions in an aircraft, they did provide a good indication of the
conditions occurring during flight in a typical aircraft fuel tank. The results from the
simulated flight profile tests, including the environmental flight conditions and ullage
vapor concentration comparisons are shown in figures 5.12 – 5.17.
Figures 5.13, 5.15, and 5.16 show a comparison between calculated and measured
ullage vapor concentrations for three flight scenarios with cruises at 10,000’, 20,000’, and
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1.5
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% Propane Equivalent
42