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

1.3 Objectives of the Thesis
The ultimate goal for fuel tank protection research is to determine methods, or
procedures, that can eliminate the possibility of fuel tank fires and explosions. Fuel
vaporization modeling can be used to estimate the fuel vapor concentration in the ullage
of a fuel tank as a function of the tank pressure and temperature. Such a model can be
valuable to the fuel tank protection cause, as computer modeling reduces the cost and
time of full-scale experimentation. The model calculations can also be used for fuel tank
inerting requirements or to verify the intrinsic safety of an inert fuel tank. The objective
of this study is to generate experimental data on fuel vaporization for tank conditions
appropriate to those encountered in an aircraft fuel tank. The data obtained can then be
available for validating the estimations from vaporization models.
To that effect, an experiment was designed to simulate an in-flight environment
around a fuel tank and measure tank conditions. The experimental setup consisted of a
simulated fuel tank with a uniformly heated floor surface and unheated sidewalls and top
surface. The tank was instrumented with thermocouples and a total hydrocarbon detector
for measuring the vapor concentration in the ullage gas. The fuel tank was situated in an
environmental chamber that could vary the ambient pressure and temperature to simulate
flight conditions. Data was collected for different pressure and temperature conditions
using JP-8 as the evaporating liquid. A limited number of tests were also performed
using isooctane (2-2-4 trimethylpentane) as the test liquid. The data was compared with
predictions from an available fuel vaporization model [11] that was also used to assess
the flammability of the vapor generated and for discussion of the overall transport
processes occurring within the fuel tank.
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