H-2 CARS THERMOMETRY IN A FUEL-RICH, PREMIXED, LAMINAR CH4/AIR FLAME IN THE PRESSURE RANGE BETWEEN 5 AND 40 BAR

To establish H-2 CARS thermometry at high pressure, accumulated H(2)Q-branch CARS spectra were recorded in the exhaust of a fuel-rich CH4/air flame at pressures between 5 and 40 bar. Temperatures were deduced by fitting theoretical spectra to experimental data points. The Energy-Corrected Sudden (ECS) scaling law was employed to set up an empirical model for the calculation of H-2 linewidths in high-pressure hydrocarbon flames with H-2 as a minority species. Experimental H-2 CARS spectra could be simulated very accurately with this model. The evaluated temperatures agreed well with reference temperatures obtained by spontaneous rotational Raman scattering of N-2.