Fully quantitative two-dimensional measurements of liquid- and vapor-phase fuel distributions (mass per unit volume) from high-pressure direct-injection gasoline injectors are reported for conditions of both slow and rapid vaporization in a heated, high-pressure spray chamber. The measurements employ the coevaporative gasoline-like fluorobenzene (FB)/ diethylmethylamine (DEMA)/hexane exciplex tracer/fuel System. In contrast to most previous laser-induced exciplex-fluorescence (LIEF) experiments, the quantitative results here include regions in which liquid and vapor fuel coexist (e.g. near the injector exit). A unique aspect is evaluation of both vapor- and liquid-phase distributions at varying temperature and pressure using only in situ vapor-phase fluorescence calibration measurements at room temperature and atmospheric pressure. This approach draws on recent extensive measurements of the temperature-dependent spectroscopic properties of the FB-DEMA exciplex system, in particular on knowledge of the quantum efficiencies of the vapor-phase and liquid-phase (exciplex) fluorescence. In addition to procedures necessary for quantitative measurements, we discuss corrections for liquid-vapor crosstalk (liquid fluorescence that overlaps the vapor-fluorescence bandpass), the unknown local temperature due to vaporization-induced cooling, and laser-sheet attenuation by scattering and absorption.
Quantitative liquid and vapor distribution measurements in evaporating fuel sprays using laser-induced exciplex fluorescence
Quantitative Messungen der Flüssigkeits- und Dampfverteilung im evaporierten Kraftstoffnebel mittels laserinduzierter Exciplex-Fluoreszenz
Measurement Science and Technology ; 20 , 12 ; 125401/1-125401/13
2009
13 Seiten, 12 Bilder, 1 Tabelle, 38 Quellen
Article (Journal)
English
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