Quantitative Measurements of Chemiluminescence in a Laminar Methane–Air Premixed Flame and Comparison to Numerical Methods

Abstract

Quantitative measurements of chemiluminescence emissions as a result of CH*, OH*, C 2 *, and CO 2 * were conducted in CH 4 /air premixed flames at different equivalence ratios (θ = 0.7−1.33), and numerical results based on onedimensional flame simulations were compared to these data. A wavelength-dependent and optical-path-corrected emission calibration method was applied to quantify the emission of each excited species. The numerically simulated emission intensities of OH* and CH* are within the same order of magnitude as the experimental values for the same flame conditions. When selfabsorption and cooling water thermosteresis are taken into account, the simulated OH* values are 1.0−1.4 times greater than the experimental results, while the CH* values are approximately 2.3−4.1 times greater. These findings suggest that more work is required to refine the temperature dependence factors for the CH* formation rate coefficients at high temperatures.

Quantitative Measurement of OH* and CH* Chemiluminescence in Jet Diffusion Flames

“…However, they failed to take into account the effects of nonradiative transitions of OH*. It is noteworthy that Wang et al 35 introduced a Monte Carlo tracing of photons to correct the optical paths of a CH 4 /air plane premixed flame, and the wavelength responsivity of the optical detection system was calibrated using a quartz tungsten halogen lamp. They found that the concentration distributions of CH*, OH*, C 2 *, and CO 2 * are consistent with simulation results, but this method only works for one-dimensional plane flames.…”

Temperature and CH* measurements and simulations of laminar premixed ethylene jet-wall stagnation flames

“…Further work has examined and sought to optimize the prediction of flame location [32]. Full coupling of sub-mechanisms for CH* were previously shown to have negligible effects on the flame characteristics due to its orders of magnitude difference in concentration [33,34]…”