Experimental investigation of OH*/CH* ratio variations in turbulent, disk stabilized, lean propane-air flames with inlet mixture preheat and stratification

Flame Emission Spectroscopy Analysis of Distributed Liquid Fuel Combustion

“…The heat release correlates well with OH* and CH* [13], and their ratio is widely used to determine ϕ; therefore, the effect of thermal power can be canceled [14,15]. Generally, OH*/CH* properly correlates with ϕ in the case of gaseous fuel combustion [16,17], while liquid fuels behave differently due to droplet combustion and the less homogeneous fuel-air mixture [18]. Consequently, checking the OH*/CH* of distributed combustion is critical since such flames feature much more homogeneous mixtures for liquid fuels.…”

Four-Line C2*/CH* Optical Sensor for Chemiluminescence Based Imaging of Flame Stoichiometry

“…The developed calibration curves of C 2 */CH* vs. Φ can then be used to track local or transient flame dynamics, such as heat release-rate fluctuations or lean blowout [ 28 , 29 ]. OH* and CH* are also commonly used pairs of radical species for chemiluminescence imaging [ 16 , 25 , 30 , 31 , 32 , 33 ]. Chemiluminescence intensity ratios have been used to examine local variations in the species’ intensities and how they relate to the flame structure [ 15 , 16 , 31 , 32 ].…”

“…OH* and CH* are also commonly used pairs of radical species for chemiluminescence imaging [ 16 , 25 , 30 , 31 , 32 , 33 ]. Chemiluminescence intensity ratios have been used to examine local variations in the species’ intensities and how they relate to the flame structure [ 15 , 16 , 31 , 32 ].…”