Jahrestreffen der DECHEMA/VDI-Fachgruppe Lebensmittelverfahrenstechnik 25. – 27. Feb. 2026, Karlsruhe
Abtract:
This work presents the theoretical foundations of an optical measurement method for the characterization of individual dynamic double-emulsion droplets. In previous studies [1], the characterization of complex droplets containing highly absorbing particles was investigated theoretically and confirmed experimentally. The aim of this work is to demonstrate that a light-scattering signal recorded by a TSTOF [2] measurement instrument contains physical information suitable for the characterization of double emulsions. To this end, simulations using a 3D ray-tracing method [3] are performed to identify correlations between the scattering signals and the characteristic properties of double-emulsion droplets. Both water droplets containing an inner oil droplet and the inverse configuration are considered, with the size ratios systematically varied.
For experimental validation, clear-coat–coated glass beads are used in a drop tower to simulate the dynamics of individual droplets. In further investigations, double-emulsion sprays are generated and their light-scattering signals are clustered using artificial intelligence to identify possible droplet families. The presented method is novel and demonstrates high potential for applications in the analytical investigation and monitoring of mixing processes.
References
[1] Schaefer, W., Fleck, S., Haas, M., & Jakobs, T. (2025). Optical Measurement Method for Monitoring High-Mass-Concentration Slurry Sprays: An Experimental Study. Photonics, 12(7), 673. https://doi.org/10.3390/photonics12070673
[2] Schaefer, W.; Li, L.; Stegmann, P.; Terada, M. Technical Report on the TSTOF Measurement Method: Technical Basics, Historical Development, and Comparison with Other Laser-Based Measurement Methods. Photonics 2026, 13, 56. https://doi.org/10.3390/photonics12070673
[3] Li, Lingxi, et al. “Simulation of Light Scattering from a Colloidal Droplet Using a Polarized Monte Carlo Method: Application to the Time-Shift Technique.” Optics Express, vol. 27, no. 25, Dec. 2019, p. 36388, https://doi.org/10.1364/oe.27.036388