This investigation aims at ‘‘thermal product” determination in millisecond time durations, for coaxial surface junction thermocouples through laboratory experiments. For this purpose, two types of CSJTs (E and J) are fabricated in-house and their sensitivities are obtained through oil-bath calibration experiments. The results show that E-type CSJTs have higher sensitivity value (59 lV/C) as compared to J-type CSJTs (44 lV/C) which is an indication of higher magnitude of voltage signal for same temperature rise. Experimentally, the TP values are determined through ‘‘waterdroplet and water-plunging techniques” in which the both types of CSJTs are exposed to impulse heat loads. The corresponding transient temperature histories are captured and subsequently TP values are calculated. While comparing them with theoretical
estimates, the results show encouraging agreements except for a particular case in which the TP value was under-predicted in ‘‘water-plunging” experiment for J-type CSJT. The temperature histories are further used to calculate surface heat flux and a very good comparing is found among all the experimental results. All the experimental results of sensitivity, temperature and surface heat fluxes are found to be accurate within an experimental uncertainty of ±10%. The techniques discussed in this paper has a great significance in determining TP values experimentally for millisecond
durations particularly for CSJTs fabricated from metallic alloys for which there are not any exact theoretical estimates.