Operating Characteristics of a Propylene Charged Loop Heat Pipe with Potential Spacecraft Applications.
Abstract
Heat pipes have been in use for spacecraft thermal control since the early 197Os. They offer the advantages of high thermal conductance with relatively low mass, but suffer the liabilities of a rigid configuration and sensitivity to adverse acceleration (exemplified by the evaporator raised over the condenser in earth's gravity field). The Loop Heat Pipe was developed in Russia specifically to address these concerns. Using a metal matrix wick with relatively high capillary pumping capacity and careful fluid inventory management, the Loop Heat Pipe is claimed to be fully self priming and capable of withstanding high adverse acceleration. The above factors also allow the vapor and liquid to travel through very small lines (3 mm OD), providing a highly flexible installation. The Loop Heat Pipe appears to be a valuable technology for future spacecraft development, but little performance data is available. Martin Marietta has purchased two Loop Heat Pipes (one charged with propylene and one with ammonia) from the Lavoclikin Association in Russia. The ammonia pipe was tested by Martin Marietta Astronautics Group in Denver, and the propylene pipe by the author at Philips Laboratory under a Memorandum of Agreement between Martin Marietta and the Air Force Materiel Command. The results presented show that while the propylene charged pipe is not capable of transferring the heat carried by the ammonia pipe, it has otherwise similar characteristics. Failure modes and recovery procedures are documented, and recommendations for further study are included.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1995
- Accession Number
- ADA304826
Entities
People
- Joseph A. Gherlone Jr
Organizations
- Naval Postgraduate School