The impact of single droplets on hot surfaces is part of the spray-wall interaction of many industrial processes such as internal combustion in engines and gas turbines as well as spray cooling. The interaction of sprays, or single drops, with the surface has a significant influence on process parameters such as the transferred heat, homogeneity of heat transfer and secondary droplet sizes.
In order to generate a detailed physical understanding of processes involving droplets under extreme environmental conditions, the Collaborative Research Center Transregio 75 ‘Droplet Dynamics under Extreme Ambient Conditions’ was established by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) in January 2010. The Collaborative Research Center is divided into the three project areas "A Methodological Foundations", "B Free Drops" and "C Drops with Wall Interactions", which are being investigated collaboratively at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, Lampoldshausen), TU Darmstadt, University of Stuttgart and University of Paderborn.
The single drop impact on a heated surface is investigated in subproject C4 at the Institute for Fluid Mechanics and Aerodynamics in Darmstadt. An experimental setup was developed to study and characterize the drop impact depending on the impact parameters, liquid properties, surface temperature, surface material, surface properties and ambient pressure. For this purpose, different measurement techniques, such as high-speed cameras with telecentric lenses, far-field microscopes, high-speed infrared cameras and inverse thermal conduction solvers are used. Based on the experiments, various physical models have been developed, validated and published.
