Experimental Thermal Performance Testing of Cryogenic Tank Systems and Materials

Myers, Wesley C ; Fesmire, J E

关键词: THERMAL CONDUCTIVITY;    CRYOGENIC TANKS;    CRYOGENICS;    LOW TEMPERATURE TESTS;    CALIBRATING;    LIQUID NITROGEN;    PERFORMANCE TESTS;    TEMPERATURE EFFECTS;    HEAT TRANSFER;    CRYOSTATS;    CALORIMETERS;    HEAT MEASUREMENT;    THERMAL VACUUM TESTS;    TEST CHAMBERS;    INSULATION;    LOW DENSITY MATERIALS;   

RP-ID  :  KSC-E-DAA-TN53905

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

A comparative study was conducted to collect and analyze thermal conductivity data on a wide variety of low density materials, as well as thermal performance data on a number of vacuum-jacketed cryogenic tank systems. Although a vast number of these types of materials and cryogenic tank systems exist, the thermal conductivity of insulation materials and the thermal performance of cryogenic tank systems is often difficult to compare because many industrial methods and experimental conditions are available and utilized. The availability of a new thermal conductivity measurement device, the Macroflash Cup Cryostat, which is applicable for assessing a variety of materials, is accessible at NASA's Cryogenic Test Laboratory (CTL) at the Kennedy Space Center (KSC). The convenience of this device has resulted in the ability to rapidly measure the thermal conductivity properties of these materials by using a flat-plate liquid nitrogen (LN2) boiloff technique that employs a guarded heat flow test methodology in order to determine the effective thermal conductivity (ke) of a test specimen. As the thermal conductivities are measured at cryogenic temperatures, materials suitable for both future space missions and cryogenic tank systems can be identified and experimentally analyzed. Also recognizable are materials which may help increase energy efficiency by limiting the thermal losses encountered under various environmental conditions. The overall focus of this work consisted of two parts. One part, was to produce and analyze thermal conductivity data on a wide variety of materials with suitable properties conducive to those needed to aid in the production of a calibration curve for the "low end" of the Macroflash instrument. (Low end meaning materials with a thermal conductivity rating below 100 milliwatts per meter-Kelvin). The second part was to collect and analyze heat transfer data for a variety of small vacuum-jacketed vessels (cryogenic tank systems) in order to compare the thermal performance between them.