| Popis: |
Spectroscopic measurements of OH-radical and O-atom concentrations are analyzed for high-intensity turbulent combustion of methane/air in a modified Longwell jet-stirred reactor at conditions P=0.92 atm, ΦFA=0.57 to 1,33, andm0307/V=1.89×10−2 to 4.03 ×10−2 g/cm3-s. Absolute OH concentrations were determined from the measured integrated absorption of resolved spectral lines in the OH2π-2+ (0,0) band. Atomic oxygen was inferred from chemiluminescence measured at 3500due to the radiative recombination CO+O→CO2+hv. Thermocouple temperatures varied from 1440 to 1910°K, with the OH rotational temperature being greater by ca. 7%. Hydroxyl radical concentrations versus equivalence ratio exhibited an apparent maximum near ΦFA≅0.85, and increased with increasingm0307/V. Partial equilibrium between OJ and O-atom was also observed in the vicinity of ΦFA≅0.85. The peak O-atom concentration occurred at FA≅0.8. Form0307/V=1.89×10−2 g/cm3-s, the peak values for OH and O-atom were 2700 and 720 ppm (molar), respectively. Calculations of NOx formation, using the PSR model with the measurements of OH and O-atom concentrations and rotational temperature as input, fell below measurements of NOx determined by gas sampling. |
