Uncertainty Analysis of Coaxial Thermocouple Calorimeters Used in Arc Jets

Driver, Dave ; Philippidis, Daniel ; Terrazas-Salinas, Imelda

关键词: ARC JET ENGINES;    CALORIMETERS;    ERROR ANALYSIS;    HEAT TRANSFER;    THERMOCOUPLES;    UNCERTAIN SYSTEMS;    HIGH TEMPERATURE TESTS;    NOSES (FOREBODIES);    SPHERICAL COORDINATES;    TWO DIMENSIONAL FLOW;   

RP-ID  :  ARC-E-DAA-TN58319

学科分类：航空航天科学

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

Recent introduction of Coaxial Thermocouple type calorimeters into the NASA Ames arc jet facilities has inspired an analysis of 2D conduction effects internal to this type of calorimeter. The 1D finite slab inverse analysis (which is typically used to deduce the heat transfer to the calorimeter) relies on the assumption that lateral conduction (i.e., 2D effects) is negligible. Most calorimeter bodies have a spherical nose, which in itself is a violation of the 1D finite slab analysis assumption. Secondly most calorimeters experience a variation in heating across the face of the body which is also a violation of the 1D finite slab analysis assumption. It turns out that these two effects tend to cancel each other to some extent. This paper shows the extent to which error exists in the analysis of the Coaxial Thermocouple type calorimeters, and also offers analysis strategies for reducing the errors.