Cylindrical boiloff calorimeters for testing of thermal insulation systems

Cryogenic Engineering Conference 2015

材料科学;物理学

Fesmire, J.E.^1 ; Johnson, W.L.^2 ; Meneghelli, B.J.^3 ; Coffman, B.E.^1

NASA Kennedy Space Center, Cryogenics Test Laboratory, UB-R1, KSC, FL

32899, United States^1

NASA Glenn Research Center, Cryogenics and Fluids 301-3, Cleveland

OH

44135, United States^2

Vencore ESC, Cryogenics Test Laboratory, ESC-830, KSC, FL

32899, United States^3

关键词: Boil-off calorimetries;    Boundary temperature;    Cylindrical configurations;    Effective thermal conductivity;    Environmental conditions;    Residual gas composition;    Thermal insulation materials;    Thermal insulation systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/101/1/012056/pdf
DOI  :  10.1088/1757-899X/101/1/012056

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Cryostats have been developed and standardized for laboratory testing of thermal insulation systems in a cylindrical configuration. Boiloff calorimetry is the measurement principle for determining the effective thermal conductivity (ke) and heat flux (q) of a test specimen at a fixed environmental condition (boundary temperatures, cold vacuum pressure, and residual gas composition). Through its heat of vaporization, liquid nitrogen serves as the energy meter, but the design is adaptable for various cryogens. The main instrument, Cryostat-100, is thermally guarded and directly measures absolute thermal performance. A cold mass assembly and all fluid and instrumentation feedthroughs are suspended from a lid of the vacuum canister; and a custom lifting mechanism allows the assembly and specimen to be manipulated easily. Each of three chambers is filled and vented through a single feedthrough for minimum overall heat leakage. The cold mass design precludes direct, solid-conduction heat transfer (other than through the vessel's outer wall itself) from one liquid volume to another, which is critical for achieving very low heat measurements. The cryostat system design details and test methods are discussed, as well as results for select thermal insulation materials. Additional cylindrical boiloff calorimeters and progress toward a liquid hydrogen apparatus are also discussed.