scholarly journals Planar laser-induced fluorescence imaging of flame heat release rate

1998 ◽  
Vol 27 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Phillip H. Paul ◽  
Habib N. Najm
Keyword(s):  
Heat Release ◽  
Fluorescence Imaging ◽  
Heat Release Rate ◽  
Release Rate ◽  
Laser Induced Fluorescence ◽  
Planar Laser Induced Fluorescence ◽  
Planar Laser

scholarly journals Burst-mode OH/CH2O planar laser-induced fluorescence imaging of the heat release zone in an unsteady flame

2018 ◽  
Vol 26 (14) ◽  
pp. 18105 ◽  
Author(s):  
Ulrich Retzer ◽  
Rongchao Pan ◽  
Thomas Werblinski ◽  
Franz J. T. Huber ◽  
Mikhail N. Slipchenko ◽  
...  
Keyword(s):  
Heat Release ◽  
Fluorescence Imaging ◽  
Laser Induced Fluorescence ◽  
Burst Mode ◽  
Planar Laser Induced Fluorescence ◽  
Planar Laser ◽  
Unsteady Flame

scholarly journals Combustion Instability of Swirl Premixed Flame with Dielectric Barrier Discharge Plasma

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1405
Author(s):  
Kai Deng ◽  
Shenglang Zhao ◽  
Chenyang Xue ◽  
Jinlin Hu ◽  
Yi Zhong ◽  
...  
Keyword(s):  
Transfer Function ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Instability ◽  
Premixed Flame ◽  
Oh Radicals ◽  
Acoustic Frequency ◽  
Planar Laser ◽  
Barrier Discharge Plasma

The effects of plasma on the combustion instability of a methane swirling premixed flame under acoustic excitation were investigated. The flame image of OH planar laser-induced fluorescence and the fluctuation of flame transfer function showed the mechanism of plasma in combustion instability. The results show that when the acoustic frequency is less than 100 Hz, the gain in flame transfer function gradually increases with the frequency; when the acoustic frequency is 100~220 Hz, the flame transfer function shows a trend of first decreasing and then increasing with acoustic frequency. When the acoustic frequency is greater than 220 Hz, the flame transfer function gradually decreases with acoustic frequency. When the voltage exceeds the critical discharge value of 5.3 kV, the premixed gas is ionized and the heat release rate increases significantly, thereby reducing the gain in flame transfer function and enhancing flame stability. Plasma causes changes in the internal recirculation zone, compression, and curling degree of the flame, and thereby accelerates the rate of chemical reaction and leads to an increase in flame heat release rate. Eventually, the concentration of OH radicals changes, and the heat release rate changes accordingly, which ultimately changes the combustion instability of the swirling flame.

Planar laser-induced fluorescence imaging of crevice hydrocarbon emissions in a spark-ignited engine

1998 ◽  
Vol 27 (2) ◽  
pp. 2069-2076 ◽  
Author(s):  
David F. Marran ◽  
Marshall B. Long ◽  
William M. Studzinski ◽  
J. Christian Swindal ◽  
William P. Acker
Keyword(s):  
Fluorescence Imaging ◽  
Laser Induced Fluorescence ◽  
Hydrocarbon Emissions ◽  
Planar Laser Induced Fluorescence ◽  
Planar Laser

scholarly journals Measurements in swirling spray flames at blow-off

2018 ◽  
Vol 10 (3) ◽  
pp. 185-210 ◽  
Author(s):  
Ruoyang Yuan ◽  
James Kariuki ◽  
Epaminondas Mastorakos
Keyword(s):  
Heat Release ◽  
Recirculation Zone ◽  
Laser Induced Fluorescence ◽  
Sauter Mean Diameter ◽  
Phase Doppler Anemometry ◽  
Planar Laser Induced Fluorescence ◽  
Spray Flames ◽  
Mean Diameter ◽  
Planar Laser ◽  
Lift Off

Various characteristics of swirling spray flames of ethanol, n-heptane, n-decane, and n-dodecane have been measured at conditions far from and close to blow-off using phase Doppler anemometry and OH* chemiluminescence, OH-planar laser-induced fluorescence, and Mie scattering at 5 kHz. The blow-off transient has also been examined. The OH* showed that the two main heat release regions lie around the spray jet at the inner recirculation zone and along the outer shear layer between the inner recirculation zone and the annular air jet. The heat release region is shortened and more attached as the flame approached blow-off. Mie images and phase Doppler anemometry data showed a wider dispersion of the ethanol spray compared to the other fuels. Similar spatial distributions of the Sauter mean diameter were observed for the four fuels for identical flow conditions, with the Sauter mean diameter value increasing with decreasing fuel volatility, but with the exception of significant presence of droplets in the nominally hollow cone for the ethanol spray. The OH-planar laser-induced fluorescence measurements showed an intermittent lift-off from the corner of the bluff body and the average lift-off height decreased with increasing air velocity, with less extinction along the inner flame branch especially for the heavier fuels. At the blow-off conditions, local extinctions appeared at both flame branches. The blow-off process followed a gradual reduction of the size of the flame, with the less volatile fuels showing a more severe flame area reduction compared to the condition far from blow-off. The average blow-off duration, [Formula: see text], calculated from the evolution of the area-integrated OH* signal, was a few tens of milliseconds and for all conditions investigated the ratio [Formula: see text] /( D/ UB) was around 11, but with large scatter. The measurements provide useful information for validation of combustion models focusing on local and global extinction.

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