Transport processes in oscillating droplets and wavy films - development of an adaptive measurement method and characteristic number-based description

Liquid films are found in many technical applications, such as falling film evaporators and packing columns. Depending on the film thickness δ and the degree of turbulence T_U, they significantly determine the heat and mass transfer of process engineering processes. As a result of instabilities in the film and depending on the surface tension of the liquid, waves form on the fluid surface.

When measuring with optical measuring methods, light refraction effects occur at the waves, which have a negative effect on the measuring accuracy. In cooperation with the Technical University of Dresden, a novel measurement methodology of Particle Image Velocimetry is developed. The measurement methodology features an adaptive optical aberration correction, which should allow reliable measurements through curved, temporally fluctuating phase interfaces for the first time. For the subsequent validation of the novel measurement method, characteristic film properties will be determined using µPIV and a confocal chromatic sensor.

This research project was funded by the Federal Ministry of Economic Affairs and Climate Action (BMWK) within the Industrial Cooperative Research (IGF) under the IGF-project number 21190 BG on the basis of a decision by the German Bundestag.