Highly Time Resolved, Combined Temperature, and Heat Flux Measurement Technique Based on ALTP Sensors

Abstract

This study demonstrates a new methodology for the simultaneous direct measurement of temperature and heat flux within the same sensing element of heat flux sensors. The methodology is demonstrated for fastresponse atomic layer thermopile (ALTP) sensors and makes use of a temperature–resistance correlation. The new methodology enables an inherent comparison and validation of the heat flux density signal of ALTPs. Good agreement is found based on experiments in the stagnation point of a subsonic hot air jet. The results of the mainly convective heat flux densities are compared against a standard coaxial thermocouple, indicating good agreement of mean values and signal characteristics. The simultaneous direct measurement of the temperature and heat flux allows the timeresolved calculation of local heat transfer coefficients and Nusselt numbers. The spectral analysis of the Nusselt number exhibits an excellent signaltonoise ratio.