Liquid butane filled load for a liner driven Pegasus experiment. Page: 2 of 5
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LIQUID BUTANE FILLED LOAD
FOR A LINER DRIVEN PEGASUS EXPERIMENT
M. A. Salazar, E. Armijo, W. Anderson, W. Atchison,
J. Bartos, F. Garcia, B. Randolph, M. G. Sheppard, J. Stokes
Los Alamos National Laboratory, MS E-549, Los Alamos, New Mexico, 87545, U.S.A.
A hydrogen rich, low density liquid, contained within
the internal volume of a cylindrical liner, was requested
of the Polymers and Coatings Group (MST-7) of the Los
Alamos Materials Science Division for one of the last
liner driven experiments conducted on the Los Alamos
Pegasus facility. The experiment (Fig.1) was a
continuation of the Raleigh-Taylor hydrodynamics series
of experiments and associated liners that have been
described previously [1,2].
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to allow monitoring the liquid level and to prevent loss of
the entire experiment as a result of possible butane loss
during the few days required to set up a Pegasus
experiment. This paper describes the load fabrication
processes and development of novel procedures that were
required. We expect to apply the technologies to future
Los Alamos experiments that will be conducted at the
new Atlas facility.
Pegasus experiment RTMIX-5 was designed to
investigate seeded instability growth at an interface
between a soft metal alloy (Sn/In) and a hydrogen rich
volatile liquid (condensed butane, C4H10) .
Approximately 10 cm3 of liquid butane (-5 g at -0.5
g/cm3) was vaporized inside the Pegasus vacuum chamber
in conducting this experiment. This release was expected
to occur about 50 ps after current start. A primary goal in
designing the experiment was to make sure that
personnel, equipment and data were protected in the
unlikely event of butane combustion.
Figure 1. Experiment Diagram.
These experiments required massive tungsten glide
planes for inertial confinement of the liner fill media
during implosion. Shallow sinusoidal perturbations were
machined on the inside surface of the liner to seed
instabilities, also true of the previous experiments. Butane
was selected for a relatively low equilibrium vapor
pressure, a practical attribute for use in the Pegasus
vacuum power flow channel. Butane safety topics at
Pegasus are addressed. Glide planes were sealed to the
liner by use of butane compatible o-rings. A sintered form
of tungsten was used for the glide planes to facilitate
machining the relatively complex shapes that were
required. Porosity of the tungsten was sealed by an epoxy
vacuum/pressure impregnation procedure. Following
some development experiments, we chose to pre-fill the
load with butane and seal the liner assembly as opposed
to filling the load after being installed in the target
chamber at Pegasus. A butane reservoir was developed
and mounted above the load as a part of the load assembly
II. TEST FILL APPARATUS
The test fill apparatus is shown in Fig.2. An acrylic
chamber duplicates the dimensions of the experimental
volume. It uses the tungsten glide planes of the
experiment and an acrylic reservoir for containing a
visible head of liquid butane above the liner experiment.
This device revealed the tungsten glide planes leaked
through the porosity of the sintered metal. Oil seeped
from the pores after exposure to liquid butane. Pore
sealing techniques were developed as described below.
Techniques for butane filling and for keeping bubbles out
of the test volume were developed with this apparatus in a
fume hood. Vacuum was applied to the test volume to
mimic the Pegasus vacuum power flow channel. Butane
was introduced at the bottom of the liner volume. Venting
at the top valve of the reservoir was required to fill the
two volumes. The target volume was cooled with sprayed
canned air to condense butane without trapping bubbles.
To prevent bubble formation within the test volume after
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Salazar, M. A. (Mike A.); Armijo, E. V. (Elfino V.); Anderson, W. E. (Wallace E.); Atchison, W. L. (Walter L.); Bartos, J. J. (Jacob J.); Garcia, F. (Fermin) et al. Liquid butane filled load for a liner driven Pegasus experiment., article, January 1, 2001; United States. (https://digital.library.unt.edu/ark:/67531/metadc929163/m1/2/: accessed April 26, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.