Distribution of OH and CH Radicals in the Boundary Layer with Ethanol Combustion

Abstract

The influence of free-stream turbulence on the distributions of CH and OH radicals is studied with the use of optical methods of measurements in focused beams. The data on CH concentration are obtained for the minimum level of turbulence, and the OH concentration profiles are obtained for three levels of velocity fluctuations: 1, 8, and 18%. It is shown that the regions where the OH and CH radicals are observed in the laminar boundary layer are shifted from the temperature maximum toward the oxidizer zone and toward the fuel zone, respectively. The highest level of the OH concentration is close to values typical of hydrogen combustion. The root-meansquare fluctuations of velocity and the mean values of the OH concentration vary nonmonotonically along the flame.

Effect of heat transfer on the distributions of OH and CH radicals in the boundary layer with ethanol combustion

“…Data on the absolute hydroxyl concentrations were obtained by the method of laser-induced fluorescence (LIF). Similar measurements were performed in boundary layers during ethanol combustion [11,12]. It was demonstrated that the coordinates of the OH and temperature maximums do not coincide, and the CH radical distribution has two maximums.…”

“…The present activities continue the research described in [11,12]. The goal is to find the boundaries of the heat-release region and heat-release intensity on the basis of experiments performed and to study the dependence of these factors on different transport mechanisms.…”

The effect of lambda-doublet levels in ethanol flame temperature estimation

“…These measurements are important, for example, for analyzing the combustion kinetics and determining the combustion efficiency. 3 Laser induced fluorescence (LIF) has been used to measure temperature and concentration of OH and CH radicals in ethanol flames. 3,4 This method is based on laser-induced excitation of a specific species and subsequent measurement of their fluorescence.…”

“…3 Laser induced fluorescence (LIF) has been used to measure temperature and concentration of OH and CH radicals in ethanol flames. 3,4 This method is based on laser-induced excitation of a specific species and subsequent measurement of their fluorescence. On the other hand, natural emission, or chemiluminecence, of the species also can be used for temperature measurement of flame.…”

Temperature measurements by oh lif and chemiluminescence kinetic modeling for ethanol flames

“…[5][6][7] The increase of ethanol use, as the examples above, has stimulated several studies on ethanol oxidation through different techniques, wherein the main aims are the combustion evaluation and the pollutant formation. [8][9][10][11][12][13][14][15][16][17][18][19][20][21] From these works, detailed reaction mechanisms have been proposed for ethanol combustion.…”