We discovered experimentally
the importance of wind variations
in influencing both vapordrift
downwind and the size of the LNG
vapor cloud over the pond. This latter effect was large enough to
significantly influence our calculations on spill 4. We had to estimate
the vapor source size from
Ongoing experiments
We are currently performing
40-m° spill experiments at China
Lake with a much more extensive
acquisition center and the stations,
and the need to movestations during the experimental series, it has
been impractical to link the instru-
sensor array (Fig. 6). These tests
began in June and will end in
September. Because of the large
250 PUTT TTT TTT
photographs, since our otherin-
strumentation was not designed to
7 Pig. D
Fn Anarad
4
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ments to the acquisition center with
| (a) Methane
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measure it.
Our data and calculations
showed that the lower flammable
limit of the vapor cloud (33 g/m*)
extended farther than expected
and that the cloud was warmer
than predicted. However, the code
calculations were in reasonable
- agreement with the concentration
data for the individual samplingstations. We believe that this agreement is due mainly to the code’s
ability to recreate the time and
spatial variations in the wind field.
To improve our predictive ability,
we will need to consider the effects
of the large density difference between the cold gas cloud and the air
and to refine our methods of
modeling the effects of terrain
features such as hills and valleys.
number of stations involved, the
large distances between the data-
—
Concentrations of
hydrocarbons atsta-
tion 4 during the second 5-m’spill,
measured with an Anarad infrared
sensor that distinquished
(a)methane, (b) ethane, and
(c)propane. The ethane and
propane concentration peaks at
about 100s provide the first field
evidenceof differential boiloff of the
various hydrocarbon fractions
released in an LNG spill.
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