Effervescent Atomizér - Výzkum struktury spreje pomocí PIV - PLIF Techniky

Effervescent Atomizer - Study of Spray Structure Using PIV - PLIF Technique

conference paper

en

Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are employed to study an effervescent atomizer generated spray. Double pulsed laser provides two pulses of 265 nm radiation. The pulses are converted to a light sheet illuminating the spray in a cross section perpendicular to the spray axis. Natural fluorescence of the light heating oil is used for measurement of instant liquid phase concentration. Simultaneous 3D velocity field is calculated using the image pairs of liquid conc. Combination of the velocity and the conc. image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid conc. and mass flux. Space-resolved RMS fluctuations of both the values from average local value normalized by the local time-average value characterize space-resolved spray unsteadiness. The spatial distribution of both the liquid conc. and mass flux is similar; the spray is axially symmetrical with maximum of time-average mass flux (conc.) in spray axis. Radial profiles of the norm. RMS fluctuations of the mass flux (conc.) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Radial profiles of the mean values and mainly of the fluctuations of the mass flux (conc.) vary with change of atomizer operation conditions.

Planar Laser-Induced-Fluorescence a stereo- Particle Image Velocimetry jsou použity pro výzkum spreje u trysky typu effervescent. Pomocí přirozené fluorescence LTO je měřena koncentrace kapaliny, dále je měřeno 3D rychlostní pole kapek spreje a kombinací obou veličin je vypočten okamžitý hmotnostní tok kapaliny ve spreji. Jsou vyhodnoceny časově průměrné a RMS hodnoty těchto veličin a na jejich základě je pak analyzována struktura spreje při různých provozních podmínkách.

Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are employed to study an effervescent atomizer generated spray. Double pulsed laser provides two pulses of 265 nm radiation. The pulses are converted to a light sheet illuminating the spray in a cross section perpendicular to the spray axis. Natural fluorescence of the light heating oil is used for measurement of instant liquid phase concentration. Simultaneous 3D velocity field is calculated using the image pairs of liquid conc. Combination of the velocity and the conc. image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid conc. and mass flux. Space-resolved RMS fluctuations of both the values from average local value normalized by the local time-average value characterize space-resolved spray unsteadiness. The spatial distribution of both the liquid conc. and mass flux is similar; the spray is axially symmetrical with maximum of time-average mass flux (conc.) in spray axis. Radial profiles of the norm. RMS fluctuations of the mass flux (conc.) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Radial profiles of the mean values and mainly of the fluctuations of the mass flux (conc.) vary with change of atomizer operation conditions.

Planar Laser-Induced-Fluorescence, Particle Image Velocimetry, effervescent atomizér, koncentrace kapaliny, rychlostní pole, hmotnostní tok kapaliny, nestability spreje.

Planar Laser-Induced-Fluorescence, stereoscopic Particle Image Velocimetry, effervescent atomizer, liquid phase concentration, velocity field, liquid mass flux, spray unsteadiness.

2007

11.09.2007

Faculty of Engineering, University "La Sapienza", Rome, Italy

Rome, Italy

The seventh International Symposium PIV 2007

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