Detail publikace

Nestability v Effervescent Sprejích - Měření a vyhodnocení pomocí kombinovaného PIV-PLIF Techniky

JEDELSKÝ, J. JÍCHA, M.

Originální název

Unsteadiness in Effervescent Sprays - Measurement and Evaluation using Combined PIV-PLIF Technique

Český název

Nestability v Effervescent Sprejích - Měření a vyhodnocení pomocí kombinovaného PIV-PLIF Techniky

Anglický název

Unsteadiness in Effervescent Sprays - Measurement and Evaluation using Combined PIV-PLIF Technique

Typ

článek ve sborníku

Jazyk

en

Originální abstrakt

Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are simultaneously employed to study an effervescent atomizer generated spray. Light heating oil is continuously atomized using air as an atomizing medium. 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 instant liquid phase concentration distribution measurement. Simultaneous 3D velocity field is calculated using image pairs of the liquid concentration. Combination of the velocity component vertical to the laser light sheet and the concentration image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid concentration and mass flux. Space-resolved fluctuations of both the values from average local value are evaluated. Root-mean-square of the liquid concentration fluctuations and mass flux fluctuations normalized by the local time-average value is used to characterise space-resolved spray unsteadiness. Results show similar spatial distribution of both the liquid concentration and mass flux. The spray is axially symmetrical with maximum of time-average mass flux (concentration) in spray axis. Radial profiles of the normalized RMS fluctuations of the mass flux (concentration) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Influence of atomizer operation conditions on the spray structure is also investigated. The atomizer is operated in the range of air gauge pressure 0.1 - 0.5 MPa and Gas-to-Liquid-Ratio by mass (GLR) of 2 - 50%. Results document that radial profiles of the mean values and mainly of the fluctuations of the mass flux (concentration) vary with change of operation conditions. The spray unsteadiness is relatively low in case of high GLR with increasing tendency for decreasing GLR. Influence of pressure is not so significant.

Český abstrakt

Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are simultaneously employed to study an effervescent atomizer generated spray. Light heating oil is continuously atomized using air as an atomizing medium. 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 instant liquid phase concentration distribution measurement. Simultaneous 3D velocity field is calculated using image pairs of the liquid concentration. Combination of the velocity component vertical to the laser light sheet and the concentration image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid concentration and mass flux. Space-resolved fluctuations of both the values from average local value are evaluated. Root-mean-square of the liquid concentration fluctuations and mass flux fluctuations normalized by the local time-average value is used to characterise space-resolved spray unsteadiness. Results show similar spatial distribution of both the liquid concentration and mass flux. The spray is axially symmetrical with maximum of time-average mass flux (concentration) in spray axis. Radial profiles of the normalized RMS fluctuations of the mass flux (concentration) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Influence of atomizer operation conditions on the spray structure is also investigated. The atomizer is operated in the range of air gauge pressure 0.1 - 0.5 MPa and Gas-to-Liquid-Ratio by mass (GLR) of 2 - 50%. Results document that radial profiles of the mean values and mainly of the fluctuations of the mass flux (concentration) vary with change of operation conditions. The spray unsteadiness is relatively low in case of high GLR with increasing tendency for decreasing GLR. Influence of pressure is not so significant.

Anglický abstrakt

Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are simultaneously employed to study an effervescent atomizer generated spray. Light heating oil is continuously atomized using air as an atomizing medium. 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 instant liquid phase concentration distribution measurement. Simultaneous 3D velocity field is calculated using image pairs of the liquid concentration. Combination of the velocity component vertical to the laser light sheet and the concentration image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid concentration and mass flux. Space-resolved fluctuations of both the values from average local value are evaluated. Root-mean-square of the liquid concentration fluctuations and mass flux fluctuations normalized by the local time-average value is used to characterise space-resolved spray unsteadiness. Results show similar spatial distribution of both the liquid concentration and mass flux. The spray is axially symmetrical with maximum of time-average mass flux (concentration) in spray axis. Radial profiles of the normalized RMS fluctuations of the mass flux (concentration) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Influence of atomizer operation conditions on the spray structure is also investigated. The atomizer is operated in the range of air gauge pressure 0.1 - 0.5 MPa and Gas-to-Liquid-Ratio by mass (GLR) of 2 - 50%. Results document that radial profiles of the mean values and mainly of the fluctuations of the mass flux (concentration) vary with change of operation conditions. The spray unsteadiness is relatively low in case of high GLR with increasing tendency for decreasing GLR. Influence of pressure is not so significant.

Klíčová slova

effervescent atomizace, PLIF, PIV, nestability spreje

Rok RIV

2006

Vydáno

01.06.2006

Nakladatel

Calouste Gubelkian foundation, Lisbon, Portugal

Místo

Lisbon, Portugal

Strany od

1

Strany do

10

Strany počet

10

BibTex


@inproceedings{BUT20095,
  author="Jan {Jedelský} and Miroslav {Jícha}",
  title="Unsteadiness in Effervescent Sprays - Measurement and Evaluation using Combined PIV-PLIF Technique",
  annote="Planar Laser-Induced-Fluorescence and stereoscopic Particle Image Velocimetry are simultaneously employed to study an effervescent atomizer generated spray. Light heating oil is continuously atomized using air as an atomizing medium. 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 instant liquid phase concentration distribution measurement. Simultaneous 3D velocity field is calculated using image pairs of the liquid concentration. Combination of the velocity component vertical to the laser light sheet and the concentration image leads to instant planar liquid mass flux. Set of 256 image pairs is used to calculate time averaged image of the liquid concentration and mass flux. Space-resolved fluctuations of both the values from average local value are evaluated. Root-mean-square of the liquid concentration fluctuations and mass flux fluctuations normalized by the local time-average value is used to characterise space-resolved spray unsteadiness. Results show similar spatial distribution of both the liquid concentration and mass flux. The spray is axially symmetrical with maximum of time-average mass flux (concentration) in spray axis. Radial profiles of the normalized RMS fluctuations of the mass flux (concentration) distribution show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Influence of atomizer operation conditions on the spray structure is also investigated. The atomizer is operated in the range of air gauge pressure 0.1 - 0.5 MPa and Gas-to-Liquid-Ratio by mass (GLR) of 2 - 50%. Results document that radial profiles of the mean values and mainly of the fluctuations of the mass flux (concentration) vary with change of operation conditions. The spray unsteadiness is relatively low in case of high GLR with increasing tendency for decreasing GLR. Influence of pressure is not so significant.",
  address="Calouste Gubelkian foundation, Lisbon, Portugal",
  booktitle="Proceedings of 13th International Symposium on Applications of Laser Techniques to Fluid Mechanics",
  chapter="20095",
  edition="1",
  institution="Calouste Gubelkian foundation, Lisbon, Portugal",
  year="2006",
  month="june",
  pages="1--10",
  publisher="Calouste Gubelkian foundation, Lisbon, Portugal",
  type="conference paper"
}