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

layer of spatially uniform but temporally varying temperature and thickness, with the
condensate layer temperature equal to the tank wall temperature.
The species mass balance for the control volume defined by the bulk gas within
the ullage, including the rate of species vaporization, condensation, and outflow:
( m
− m
)( 1− ) ± m
, i = → N
mi ei ci iN oi
67
= δ 1
( 8 )
Gases were assumed to follow ideal gas behavior so that mi was written as:
m
i
xi
M i pV
= , i = 1 → N
( 9 )
RT
g
Substituting and solving for the variation of species mole fraction within the gas control
volume:
RTg
⎡
m dp m dTg
⎤
i
i
x
i = ⎢(
m
ci − m
ei )( 1− δ iN ) ± m
oi − + ⎥,
i = 1 → N ( 10 )
M iVp
⎢⎣
p dt Tg
dt ⎥⎦
Summation of the terms in equation 10 over all species resulted in the following
relationship for the total rate of mass inflow or outflow:
N
mo i 1 M i
inflow: − ∑
=
m o
outflow: =
M
1
N
=
1
M
N
N m dp m dT i g
, i = 1 → N ( 11 )
M p dt M T dt
( m − m
)( 1−
δ )
i
∑ ci ei i − ∑ + ∑
i=
1 i
i=
1 i
i=
1
The ullage control volume energy balance was given by the following relationship, which
was used to compute the ullage temperature:
i
g