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A 6-meter prototype cryogenic transfer line with magnetic suspension was tested for its mechanical and thermal performance at the Cryogenics Test Laboratory of NASA Kennedy Space Center (KSC). A test facility with two cryogenic end-boxes was designed and commissioned for the testing. Suspension mechanisms were verified through a series of tests with liquid nitrogen. The thermal performance of the prototype was determined using the new test apparatus. The tested prototype has incorporated temperature and vacuum pressure data acquisition ports, customized interfaces to cryogenic end-boxes, and instrumentation. All tests were conducted under simulated onsite transfer line working conditions. A static (boiloff rate measurement) testing method was employed to demonstrate the gross heat leak in the tested article. The real-time temperature distribution, vacuum level, levitation distance, and mass flow rate were measured. The main purpose of this paper is to summarize the testing facility design and preparation, test procedure, and primary test results. Special arrangements (such as turning on/off mechanical support units, observing levitation gap, and setting up the flowmeter) in testing of such a magnetically levitated transfer line are also discussed. Preliminary results show that the heat leak reduction of approximately one-third to one-half is achievable through such transfer lines with a magnetic suspension system. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Large-scale (1,000,000 liters or more) cryogenic storage tanks are typically perlite-insulated double-walled vessels. Associated problems with perlite, such as mechanical compaction and settling, could be greatly reduced by using newer bulk-fill materials such as glass bubbles or aerogel beads. Using the newer materials should translate to lower life cycle costs and improved system reliability. NASA Kennedy Space Center is leveraging its experience in the areas of materials development, insulation testing, and cryogenic systems design to develop an insulation retrofit option that will meet both industry and NASA requirements. A custom 10-liter dewar test apparatus, developed by the KSC Cryogenics Test Laboratory, was used to determine the vibration and thermal cycling effects on different bulk-fill insulation materials for cryogenic tanks. The testing included liquid-nitrogen boiloff testing and thermal cycling (with vibration) of a number of test dewars. Test results show that glass bubbles have better thermal performance and less mechanical compaction compared to perlite powder. The higher cost of the bulk material should be offset by reduced commodity loss from boiloff and improvements in material handling, evacuation, and vacuum retention. The long-term problem with settling and compaction of perlite should also be eliminated. Aerogel beads are superior for the no-vacuum condition and can now be considered in some applications. Further studies on large-scale systems are presently being pursued. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The use of ice or freeze plugs for isolating piping systems has gained wide acceptance throughout the plumbing, nuclear and petroleum industries. The reliability of the process as well as the significant cost avoidances that freeze plugs provide can benefit the cryogenics industry also. The standard method of repairing a cryogenic or high purity line was to empty the line and make the repair. The cryogenics industry also has to allow the piping to come to ambient temperature before repairs can be made. This paper describes a new process for creating a freeze plug within a pipe utilizing an alternative fluid. This process is ideally suited for application on systems where the fluid is either extremely difficult to freeze, or possibly hazardous to do so. The method can also be used on high purity systems to help maintain quality requirements. The specific application described herein provides a means for isolating components in a liquid oxygen pipeline while in service, allowing the change out of components without draining the system. The cost savings, reduced handling risks and additional thermal cycling of the associated equipment and the dewar are significant. The process has been successfully employed on a large Liquid Oxygen Dewar at the Kennedy Space Center. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]