Project Details
Projekt
Optical characterisation of droplet micro-explosion in the SpraySyn burner
Applicant
Professor Dr. Sebastian Kaiser
Subject Area
Chemical and Thermal Process Engineering
Energy Process Engineering
Energy Process Engineering
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 447500013
We propose to investigate the droplet micro-explosion (DMX) in the spray-flame synthesis (SFS) on the standardized SpraySyn burner of the Priority Programme 1980 via optical imaging. In this context, DMX – the sudden disintegration of evaporating droplets due to inhomogeneous processes in their interior – has been observed directly only in single-droplet experiments. Analysis of the nanoparticles produced in these experiments and in corresponding spray flames showed that this droplet disintegration decisively influences the quality of the product made by SFS. In our own preliminary work, ultra-slow-motion imaging of the flame in the SpraySyn burner shows striking optical phenomena that strongly suggest that DMX is occurring. Therefore, we propose to first definitely detect DMX in the SpraySyn burner by direct visualization. Then its properties are to be investigated qualitatively and statistically, and to be correlated with those of the surrounding gas phase. Thus, the detailed single-droplet experiments of the project Mädler can be linked better with the overall process of SFS, supporting the modeling of that process. Statistical analysis can be used to validate those simulations that implement a physical submodel of DMX, and those that do not can be augmented with a statistical model.The primary method for the investigations will be optical imaging with high spatio-temporal resolution. A selection of methods for illumination and detection of the probably 10 – 30 micrometer diameter droplets and their explosion dynamics is to be investigated and optimized: Light scattering, fluorescence, and shadowgraphy, the latter in two variants. Finally, this high-resolution imaging of the droplets will be combined with laser-induced fluorescence imaging of the surrounding gas phase with a wider field of view but lower resolution, targeting temperature and the OH-radical as a flame marker.In addition to our own equipment, the measurements will leverage the extensive instrumentation and infrastructure of the ready-to-use Central Laboratory established as part of the Priority Programme. The laser-based measurements will be performed jointly with the project Dreier, which is developing these methods. There will also be close collaboration with the project Mädler, including extended mutual laboratory visits by the PhD students.
DFG Programme
Priority Programmes
