Heat pipe life tests described in the literature have seldom been conducted on a systematic basis. Typically one or more heat pipes are built and tested for an extended period at a single temperature with simple condenser loading. The objective of this work was to establish an approach to generate carefully controlled data that can conclusively establish heat pipe operating life with material‐fluid combinations capable of extended operation. Approximately 10 years of operational life might be compressed into 3 years of laboratory testing through a combination of increased temperature and mass fluence. To accomplish this goal test series have been identified, based on American Society for Testing and Materials (ASTM) specifications, to investigate long term corrosion rates. The heat pipes selected for demonstration purposes are fabricated from a Molybdenum‐44.5%Rhenium refractory metal alloy and include an internal crescent annular wick design formed by hot isostatic pressing. A processing methodology has been devised that incorporates vacuum distillation filling with an integrated purity sampling technique for the sodium working fluid. Energy is supplied by radio frequency induction coils coupled to the heat pipe evaporator with an input range of 1 to 5 kW per unit while a static gas gap coupled water calorimeter provides condenser cooling for heat pipe temperatures ranging from 1123 to 1323 K. The test chamber’s atmosphere would require active purification to maintain low oxygen concentrations at an operating pressure of approximately 75 torr. The test is designed to operate round‐the‐clock with 6‐month non‐destructive inspection intervals to identify the onset and level of corrosion. At longer intervals specific heat pipes are destructively evaluated to verify the non‐destructive observations. Accomplishments prior to project cancellation included successful demonstration of the heat pipe wick fabrication technique, establishment of all engineering designs, baselined operational test requirements and procurement/assembly of supporting test hardware systems.


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    Title :

    Life Test Approach for Refractory Metal/Sodium Heat Pipes


    Contributors:

    Conference:

    SPACE TECH.& APPLIC.INT.FORUM-STAIF 2006: 10th Conf Thermophys Applic Microgravity; 23rd Symp Space Nucl Pwr & Propulsion; 4th Conf Human/Robotic Tech & Nat'l Vision for Space Explor.; 4th Symp Space Coloniz.; 3rd Symp on New Frontiers & Future Concepts ; 2006 ; Albuquerque, New Mexico (USA)


    Published in:

    AIP Conference Proceedings ; 813 , 1 ; 108-116


    Publication date :

    2006-01-20


    Size :

    9 pages





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English



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