A direct-measurement thin-film heat flux sensor array

A new thin-film heat flux array (HFA) was designed and fabricated using a series of nickel/copper differential thermocouples deposited onto a thin Kapton® polyimide film. A special bank of amplifiers was designed and built to measure the signal from the HFA. Calibrations were performed to determine the gage's sensitivity and temporal response. The HFA produced signals of 42 µV (W cm−2)−1 with a measured first-order response time of 32 ms. The apparent thermal conductivity of the Kapton used was larger than what is usually reported. The design methodology, construction techniques, steady-state and transient calibrations, and a test case are all discussed.