Comparative simulation study on the dynamic thermometric performance of various thin-film thermocouples and the K-type

Transient temperature measurement in confined spaces remains a critical engineering challenge. We report the development of different types of thin-film thermocouples (TFTCs) and conducted some simulation comparisons. The static calibration shows an excellent linearity of 0.998 and a small measurement deviation of 1.13% within the temperature range of 25–200 °C. To elucidate the micro/nanoscale heat transfer mechanisms of different TFTCs, we constructed temperature-field calculations and found that the K-type TFTC has relatively limited axial heat leakage and cold-junction temperature rise under the conditions considered, with a hot-to-cold junction temperature difference of approximately 50 °C. Besides, we quantify the size effect of film thickness (from 600 to 2000 nm), demonstrating that system heat capacity and thermal leakage amplify synergistically with increasing thickness. The effects of heat-source offset and convective conditions on the sensed temperature were also investigated. This work establishes a multi-dimensional simulation framework of various types of TFTCs, which guides the material selection and engineering deployment of in-situ temperature measurement under different operational conditions.