Holographic temperature measurement on axisymmetric propane-air, fuel-lean flame

Abstract

Instead of using conventional interferometry, the whole field temperature distribution of a laminar, axisymmetric, propane-air, fuel-lean flame is measured by using an advanced digital interferometric technique, namely digital phase-shifting holographic interferometry. The measurement technique effectively improves the accuracy of conventional interferometric measurement as it circumvents the limitation of fringe counting interpolation. The results obtained by this technique are compared with those measured by conventional holographic interferometry (using interpolation) in order to evaluate the effect of interpolation on measurement accuracy. A modified dual reference beam holographic recording system is set up for this experiment and fast Fourier transformation is used for Abel inversion. The structure of the test flame is analysed by holographic visualization and measured temperature distribution. In addition, the interferometric temperature distributions are compared with thermocouple measurements. Errors introduced in the measurement are analysed and discussed.