Using the Rayleigh-Raman scattering technique, simultaneous space- and time-resolved measurements of temperature and the concentration of CO, CO2, H2, H2O, O2 and N2 have been made in pilot stabilised turbulent nonpremixed flames of CO/H2/N2 near extinction. Five photomultiplier tubes are dedicated to monitor the background chemiluminecence which is broadband and interferes in varying degrees with all the Raman lines. This interference is corrected for using correction factors which relate the charges collected on each of these monitors to the chemiluminescence interference with each of the Raman lines. It is found that as the turbulent mixing rates increase, all reactive scalars which otherwise lie close to the equilibrium limits drift gradually away from those limits due to the chemical kinetic effects becoming significant. Unlike methane flames near blowoff, localised extinction does not occurs in CO/H2/N2 flames and the mechanism of extinction for these flames is therefore different. Inferences are made regarding the spatial structure of the reaction zones in turbulent nonpremixed CO/H2/N2 flames with finite rate chemical kinetics.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
- Mechanical Engineering
- Physical and Theoretical Chemistry
- Fluid Flow and Transfer Processes