@article{,
    author = {Kögl, Matthias; Vogler, Jonas; Zigan, Lars },
    title = {Spectral Investigations of Fluorescence Tracers in Automotive and Aviation Fuels under Cryogenic Conditions},
    editor = {},
    booktitle = {},
    series = {},
    journal = {Sensors},
    address = {},
    publisher = {},
    edition = {},
    year = {2024},
    isbn = {},
    volume = {24},
    number =  {3},
    pages = {724},
    url = {https://doi.org/10.3390/s24030724},
    doi = {10.3390/s24030724},
    keywords = {Fluorescence ; Aviation ; Automotive ; Cryogenic ; Thermometry ; Fuel},
    abstract = {This study investigated spectral laser-induced fluorescence signals of dyes in fuels for
automotive and aerospace applications under low temperatures and cryogenic conditions down
to 183 K. For this purpose, a fluorescence chamber was developed based on cooling with liquid
nitrogen. The design enabled a minimal inner chamber temperature of 153 K. Furthermore, the
applicability of two-color LIF for liquid thermometry was evaluated under these conditions. The
temperature determination was based on the temperature-sensitive fluorescence intensity ratio of the
special dyes doped into the fuels determined in suitable spectral regions, which represented common
bandpass filters. For this purpose, the fluorescence signals of the dye doped into the gasoline and
jet fuel surrogate isooctane were tested as well as blends of isooctane and the ethanol biofuels E20
(comprising 80 vol.% isooctane and 20 vol.% ethanol), E40, and E100. Additionally, a realistic multicomponent
fuel Jet A-1 mixed with a suitable fluorescence dye was investigated. E100 was doped
with Eosin-Y, and the remaining fuels were doped with Nile red. Temperature-dependent spectral
LIF intensities were recorded in the range of 183 K–293 K, which simulate extreme environments for
aerospace and automotive applications. Frozen fuel–dye mixtures cause significant extinction effects
and prevent sufficient signal detection at low and cryogenic temperatures, defining the detection
limit. A temperature decrease led to a spectral shift in the emission peaks of E100 doped with Eosin-Y
toward shorter wavelengths, while the spectra of mixtures doped with Nile red were shifted toward
longer wavelengths. The suggested bandpass filters produced the temperature-sensitive intensity
ratio (the average over the temperature interval) of the dyes with the largest sensitivity for Jet A-1
(5.2%/K), followed by E100 (4.95%/K), E40 (4.07%/K), E20 (3.23%/K), and isooctane (3.07%/K),
even at cryogenic temperatures.},
    note = {},
    institution = {Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik, LRT 10 - Institut für Thermodynamik, Professur: Zigan, Lars},
    
    
}