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This content will become publicly available on August 6, 2019

Title: Uncertainty analysis of axial temperature and Seebeck coefficient measurements

Experimental investigations of solid materials at elevated temperatures rely on the optimized thermal design of the measurement system, as radiation becomes a predominant source of heat loss which can lead to large uncertainty in measured temperature and related physical properties of a test sample. Advancements in surface temperature measurements have reduced thermal losses arising from the cold-finger effect using axially inserted thermocouples and from radiation using shields or other thermal guards. The leading technology for temperature sensing at temperatures up to ~900 °C makes use of these design features for measuring thermopower, yet uncertainty analysis estimation of this technique is not known. This study makes use of finite element modeling to determine spatial temperature distributions to obtain the upper limit of confidence expected for the axially inserted thermocouple approach when a heated radiation shield is incorporated into the design. Using an axially inserted thermocouple to measure the sample surface temperature, the temperature variations across the sample hot and cold surfaces at 900 °C for a temperature drop of 0, 5, and 10 °C are calculated to be as low as 0.02, 0.21, and 0.41 °C, respectively, when a heated radiation shield is employed. Uniform temperature distribution on the thermocouple cross-wiremore » geometry indicates that the axial thermocouple measurement design is indeed effective for suppressing the cold-finger effect. Using a heated radiation shield is found to significantly reduce the temperature gradient across the thermocouples.« less
Authors:
 [1] ;  [1] ; ORCiD logo [2]
  1. Univ. of Connecticut, Storrs, CT (United States). Dept. of Mechanical Engineering
  2. Univ. of Connecticut, Storrs, CT (United States). Dept. of Mechanical Engineering; Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)
Publication Date:
Grant/Contract Number:
AC52-06NA25396; CAREER-1553987; PD17-0137
Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 8; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 30 DIRECT ENERGY CONVERSION; materials; transition metals; vacuum apparatus; thermodynamic processes; thermoelectric effects; thermal conductivity
OSTI Identifier:
1466272