Local heat transfer coefficients in spray cooling systems measured with temperature oscillation IR thermography

This paper describes the application of the temperature oscillation IR thermography method to a spray cooling system in order to measure the spatial distribution of the heat transfer coefficients with a resolution of 0.4 mm. This technique allows for the rapid and fluid-independent evaluation of the heat transfer coefficient at the back side of a heat-transferring wall, relying on radiant heating, infrared temperature measurements, and a finite difference model of the wall. The results reveal the distribution of the local heat transfer coefficients over a surface cooled by a single- and a four-nozzle array of a multi-chip spray cooling module. The area averaged results from this method were compared to previous data measured using a conventional approach with a thermal test die and were found to be in good agreement.