Two Condenser PHP(OHP) for use as a Passive Thermal Disconnect for Redundant Cryocooler Implementations
Abstract
Abstract:Redundant coolers are often desired for improved reliability of cryogenic systems. Implementations in which the backup cryocooler cools a cryogenic system that continues to operate while the non-operational cryocooler is repaired or replaced are especially desirable. Although systems with redundant coolers are preferred, the parasitic heat leak from a non-operating cooler is very large unless a thermal switch is implemented to disconnect the cooler when it isn???t working. A better solution is a passive device that is thermally conductive when a cooler is operating and thermally insulating when that cooler is not operating. A pulsating heat pipe (PHP) with two condensers, one attached to each of two crycooler cold tips will operate as a passive thermal switch for these applications.The University of Wisconsin proposes to develop and characterize the performance of a passive heat switch based on the PHP technology that we have been developing in the cryogenics lab at UW-Madison. We propose to build and test a cryogenic PHP with two condensers and to characterize its thermal performance as a function of applied heat load, fill ratio and operating temperature. The outcome of this research will be the development of the passive heat switch and the experimental characterization of the on to off conductance ratio. The proposed work will be conducted with for three operating temperatures, 4K, 40 K and 70 K using helium, neon and nitrogen as working fluid respectively.The development of the PHP based heat switch will allow the use of redundantcrycoolers without a large heat leak penalty when one of the coolers becomesinoperable. This technology will enable continuous operation for critical systemseven during cryocooler failure.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 27, 2018
- Source ID
- N000141812705
Entities
People
- Franklin Miller
Organizations
- Office of Naval Research
- United States Navy
- University of Wisconsin System