Evaluation of Alternative Thermocouple Designs for Transient Heat Transfer Measurements in Metal and Ceramic Engines

890571

02/01/1989

Event
SAE International Congress and Exposition
Authors Abstract
Content
Finite element models of various fast-response thermocouple designs have been developed. Due to the small differences in thermal properties between thermoelements and metal engine components, standard co-axial thermocouples can measure transient temperatures of metal components within an accuracy of 98%. However, these relatively small errors in total temperature measurement translate into as high as 30% errors in indicated peak-to-peak-temperature swings for iron surfaces. The transient swing errors result in up to 30% errors in peak heat flux rates to iron surfaces. These peak heat flux errors can be substantially larger if coaxial thermocouples are used for heat flux measurements in aluminum or ceramic surfaces. Increasing the thin film thickness is a compromise solution to reduce the discrepancy in peak heat flux measured with coaxial designs in metal engines. An alternative overlapping thin film thermocouple design has also been evaluated. Due to the placement of its junction away from the thermoelements, the latter design is capable of very accurate heat transfer measurements in ceramic components.
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DOI
https://doi.org/10.4271/890571
Pages
19
Citation
Assanis, D., and Badillo, E., "Evaluation of Alternative Thermocouple Designs for Transient Heat Transfer Measurements in Metal and Ceramic Engines," SAE Technical Paper 890571, 1989, https://doi.org/10.4271/890571.
Additional Details
Publisher
Published
Feb 1, 1989
Product Code
890571
Content Type
Technical Paper
Language
English