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Atmospheric Pressure Effects on Cryogenic Storage Tank Boil-OffThe Cryogenics Test Laboratory (CTL) at the Kennedy Space Center (KSC) routinely utilizes cryostat test hardware to evaluate comparative and absolute thermal conductivities of a wide array of insulation systems. The test method is based on measurement of the flow rate of gas evolved due to evaporative boil-off of a cryogenic liquid. The gas flow rate typically stabilizes after a period of a couple of hours to a couple of days, depending upon the test setup. The stable flow rate value is then used to calculate the thermal conductivity for the insulation system being tested. The latest set of identical cryostats, 1,000-L spherical tanks, exhibited different behavior. On a macro level, the flow rate did stabilize after a couple of days; however the stable flow rate was oscillatory with peak to peak amplitude of up to 25 percent of the nominal value. The period of the oscillation was consistently 12 hours. The source of the oscillation has been traced to variations in atmospheric pressure due to atmospheric tides similar to oceanic tides. This paper will present analysis of this phenomenon, including a calculation that explains why other cryostats are not affected by it.
Document ID
20120000557
Acquisition Source
Kennedy Space Center
Document Type
Conference Paper
Authors
Sass, J. P.
(NASA Kennedy Space Center Cocoa Beach, FL, United States)
Frontier, C. R.
(NASA Kennedy Space Center Cocoa Beach, FL, United States)
Date Acquired
August 25, 2013
Publication Date
July 16, 2007
Subject Category
Mechanical Engineering
Report/Patent Number
KSC-2007-116
Meeting Information
Meeting: Cryogenic Engineering Conference
Location: Chattanooga, TN
Country: United States
Start Date: July 16, 2007
End Date: July 20, 2007
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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