Correcting thermocouple measurements for radiation loss: A critical review
Thermocouples are one of the simplest and most ubiquitous experimental diagnostics in combustion research and high-temperature process flows. However, quantitative interpretation of thermocouple measurements in high-temperature environments is hampered by the need to account for important heat transfer mechanisms associated with the thermocouple wire and junction, especially thermal radiation. A number of assumptions and simplifications are of necessity incorporated in applying a radiation-correction to a thermocouple measurement, but the assumptions made in different investigations have often been poorly-documented or are inconsistent with the relevant literature guidance. This paper reviews the considerations in performing an energy balance on practical thermocouple junctions and assesses the best available information regarding the appropriate choices to make in performing radiation corrections. In particular, the effects of Nusselt number correlation, thermocouple wire and junction size, the local gas mixture transport properties, and the thermocouple emissivity are explored. The magnitude of the calculated radiation correction for different assumed values of the relevant variables is illustrated.
- Research Organization:
- Sandia National Labs., Livermore, CA (US)
- OSTI ID:
- 20002672
- Report Number(s):
- CONF-990805-; TRN: IM200002%%672
- Resource Relation:
- Conference: 33rd National Heat Transfer Conference NHTC'99, Albuquerque, NM (US), 08/15/1999--08/17/1999; Other Information: PBD: 1999; Related Information: In: Proceedings of the 33rd national heat transfer conference NHTC'99, by Jensen, M.K.; Di Marzo, M. [eds.], [1150] pages.
- Country of Publication:
- United States
- Language:
- English
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