Nonintrusive optical measurement technique for wavy liquid films: Determination of film thickness and wave structure

A noninstrusive optical measurement technique has been developed for the investigation of two-phase gas I liquid-film flow. The film analyser is capable to measure the thickness of shear or gravity driven wavy liquid films moving along a wall. On the basis of a statistical analysis of the recorded time-resolved film thickness, characteristic parameters of the film structure are calculated. Furthermore, the frequency spectrum and the dominant wave frequencies can be obtained by Fourier transformation. At present the liquid-film analyser is applied to liquid-film flows in atomizers for gas turbine combustors.