Postdoc in Advanced optical diagnostics for spray characterization- Measurement of the temperature

Laboratory: Laboratoire Energies Mécanique Théorique et Appliquée (LEMTA), UMR 7563 CNRS, Université de Lorraine, Vandœuvre-lès-Nancy, France.

Duration:12 months

LEMTA has been conducting a research activity around droplet heating, evaporation and liquid combustion for many years, with a strong experimental involvement. The project will explore luminescence-based diagnostics to characterize heat and mass transfers in sprays.

Techniques based on laser-induced fluorescence consist in seeding the liquid fuel with some organic dyes, which emit fluorescence when illuminated by a laser. The characteristics of the fluorescence signal (intensity, wavelength) vary with the temperature which can be exploited to measure the temperature of droplets [1]. However, in the case of complex liquid mixtures, difficulties remain because the fluorescence usually also depends on the chemical composition. It becomes very difficult (if not impossible) to dissociate the respective influence of temperature and composition on the fluorescence makes the measurements of the temperature impracticable.

The objective of this project will to test alternative solutions: thermographic phosphors which are photoluminescent solid microparticles sensitive to temperature [2], microcapsules filled with a fluorescent dye solution [http://iopscience.iop.org/article/10.1088/0957-0233/23/10/105306/meta], and the use of specifically tuned quantum dots. The focus will be placed more specifically on biofuels, which are of interest for reducing the carbon footprint of combustion. The final step of the project will be to study different types of aerosols under non-reactive and reactive conditions in collaboration with the team ”SAFE” of LRGP (Laboratoire Réactions et Génie des Procédés - UMR 7274 CNRS, Université de Lorraine, Nancy, France).

 

References

[1] L. Perrin, G. Castanet, F. Lemoine, "Characterization of the evaporation of interacting droplets using combined optical techniques", Experiments in Fluids, 56(2): 29, 2015

[2]C. Abram, B. Fond, F. Beyrau, "High-precision flow temperature imaging using ZnO thermographic phosphor tracer particles", Opt. Express, 23(15): 19 453-19 468, 2015