Unsteady surface heat flux and temperature measurements

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Virginia Tech


A fast response thin-film heat flux sensor was used to measure the time-resolved surface heat flux and temperature from a turbulent combustion flame impinging on a surface. Using the analytical semi-infinite conduction model, the unsteady surface heat flux was calculated from the transient temperature measurements and the surface temperature was calculated from the unsteady surface heat flux measurements.

Methods of comparing time-resolved heat flux and temperature data were presented and discussed. The standard analytical method for converting surface temperature to heat flux was used. Two new analytical methods were developed for converting heat flux to surface temperature.

The study is the first demonstration of time-resolved temperature signals generated from time-resolved heat flux measurements. The results graphically illustrate the effects of data processing on electrical noise present in the actual signal. The effect of flame unsteadiness is also shown, especially in the time-resolved heat flux measurements, which gives insight into the behavior of a propane torch. One application is for development of feed-forward control systems in industrial processes with fast transients.