Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y
Laser-induced fluorescence (LIF) spectroscopy using dyes is frequently applied for characterization of liquids and two-phase flows. The technique is utilized e.g., for mixing studies, thermometry, or droplet sizing. One major application of the LIF technique combined with Mie-scattering is the plana...
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MDPI AG
2020-10-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/20/21/5985 |
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| author | Matthias Koegl Christoph Weiß Lars Zigan |
| author_facet | Matthias Koegl Christoph Weiß Lars Zigan |
| author_sort | Matthias Koegl |
| collection | DOAJ |
| description | Laser-induced fluorescence (LIF) spectroscopy using dyes is frequently applied for characterization of liquids and two-phase flows. The technique is utilized e.g., for mixing studies, thermometry, or droplet sizing. One major application of the LIF technique combined with Mie-scattering is the planar measurement of droplet sizes in spray systems. However, its uncertainty is determined, among others, by varying dye concentration and temperature changes occurring during mixing and droplet evaporation. Systematic experimental investigations are necessary to determine the influence of dye enrichment effects on the LIF-signal of single droplets. For these investigations, the fluorescence dye Eosin-Y is dissolved in water and ethanol, which are typical solvents and working fluids in bio-medical applications and power engineering. A photo-physical characterization of the mixtures under various conditions was conducted using a spectrometric LIF setup and a micro cell. For ethanol, a small temperature dependency of the Eosin-Y LIF signal is observed up to 373 K. Photo-dissociation of Eosin-Y is negligible for solution in ethanol while it is distinct in water. The LIF signals of the single droplets are studied with an acoustic levitator. Effects of droplet evaporation, droplet deformation and varying dye concentration on the LIF-signal are studied. The single droplet measurements revealed a complex change of the fluorescence signal with reduced droplet size. This is due to droplet deformations leading to variations in the internal illumination field as well as dye enrichment during evaporation. |
| first_indexed | 2024-03-10T15:24:18Z |
| format | Article |
| id | doaj.art-1510fad346e347329309ab28da2f1844 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T15:24:18Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
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| series | Sensors |
| spelling | doaj.art-1510fad346e347329309ab28da2f18442023-11-20T18:08:37ZengMDPI AGSensors1424-82202020-10-012021598510.3390/s20215985Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-YMatthias Koegl0Christoph Weiß1Lars Zigan2Lehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, GermanyLehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, GermanyLehrstuhl für Technische Thermodynamik (LTT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, GermanyLaser-induced fluorescence (LIF) spectroscopy using dyes is frequently applied for characterization of liquids and two-phase flows. The technique is utilized e.g., for mixing studies, thermometry, or droplet sizing. One major application of the LIF technique combined with Mie-scattering is the planar measurement of droplet sizes in spray systems. However, its uncertainty is determined, among others, by varying dye concentration and temperature changes occurring during mixing and droplet evaporation. Systematic experimental investigations are necessary to determine the influence of dye enrichment effects on the LIF-signal of single droplets. For these investigations, the fluorescence dye Eosin-Y is dissolved in water and ethanol, which are typical solvents and working fluids in bio-medical applications and power engineering. A photo-physical characterization of the mixtures under various conditions was conducted using a spectrometric LIF setup and a micro cell. For ethanol, a small temperature dependency of the Eosin-Y LIF signal is observed up to 373 K. Photo-dissociation of Eosin-Y is negligible for solution in ethanol while it is distinct in water. The LIF signals of the single droplets are studied with an acoustic levitator. Effects of droplet evaporation, droplet deformation and varying dye concentration on the LIF-signal are studied. The single droplet measurements revealed a complex change of the fluorescence signal with reduced droplet size. This is due to droplet deformations leading to variations in the internal illumination field as well as dye enrichment during evaporation.https://www.mdpi.com/1424-8220/20/21/5985absorptionLIFethanolwaterdyeacoustic levitator |
| spellingShingle | Matthias Koegl Christoph Weiß Lars Zigan Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y Sensors absorption LIF ethanol water dye acoustic levitator |
| title | Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y |
| title_full | Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y |
| title_fullStr | Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y |
| title_full_unstemmed | Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y |
| title_short | Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y |
| title_sort | fluorescence spectroscopy for studying evaporating droplets using the dye eosin y |
| topic | absorption LIF ethanol water dye acoustic levitator |
| url | https://www.mdpi.com/1424-8220/20/21/5985 |
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