Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures

Abstract

Chemiluminescence emissions measurements of OH* and CH* are used to characterize the combustion of blends of methane and hydrogen in air in a constant volume combustion bomb, with two sets of initial conditions. The combined results of combustion development cover from 0.1 to 2.5 MPa. Burning velocity, heat release and unburned/burned gas temperatures are obtained from the pressure by using a two-zone thermodynamic combustion diagnostic model. Intensity of OH* and CH* increases with the initial temperature and the percentage of hydrogen, in parallel with the usual increase in burning velocity. The timings of the peaks of OH* and CH* chemiluminescence emissions are found to correlate respectively with the maximum rate of heat release and flame temperature. These results show that both chemiluminescence signals can be used to monitorize the burning process in combustion devices operating in the pressure range studied.

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

“…Excited hydroxyl radicals (OH*) are good tracers of high temperature combustion regions in a flame [28]; therefore, visualization of OH* chemiluminescence at the base of the flame allows to quantifying the lift-off length (LOL). Moreover, if an intensified high-speed camera is used, the ID can be measured too.…”

Effects of hydrogen and primary air in a commercial partially-premixed atmospheric gas burner by means of optical and supervised machine learning techniques

“…The image range intensity was not the same for G222 and G20, most probably due to the slight differences in thermal input rates (see Table 3). In addition, since the G222 fuel has relevant hydrogen content, the mean intensity difference between the OH * and CH * or C 2 * radicals is higher in the case of G222 than in G20 for all PAP [54].…”

Experimental study of influence of Liquefied Petroleum Gas addition in Hydrotreated Vegetable Oil fuel on ignition delay, flame lift off length and soot emission under diesel-like conditions

“…OH* radicals are known to be a good tracer of high temperature combustion regions in a flame [29], so that visualization of OH * -chemiluminescence at the base of the flame makes it possible to quantify the Lift-Off Length (LOL). Additionally, if an intensified high speed camera is used, ignition delay can be measured, too.…”