Carbon monoxide (CO) results from the incomplete oxidation of hydrocarbon fuels. While CO can be desirable in some syngas processes, it is a dangerous emission from fires, gas heaters, gas stoves, or furnaces where insufficient oxygen in the core reaction prevents complete oxidation of fuel to carbon dioxide and water, particularly when the reaction is interrupted by interaction with relatively cool solid boundaries. This research examines the physico-thermo-chemical processes responsible for carbon monoxide release from a small laminar non-premixed methane/air flame impinging on a nearby surface. We measure the changes in CO emission as correlated with variations in flame structure observed using planar laser induced fluorescence (PLIF of OH and 2-photon CO), and two-line OH PLIF thermometry, as a function of burner-to-plate distance. In particular, this work combines the use of OH and CO PLIF, and PLIF thermometry to describe the relative locations of the CO rich region, the peak heat release zone as indicated by chemiluminescence and OH gradients, and the extended oxidative zone in the impinging flames. The results show that CO release correlates strongly with stagnating flow-driven changes in the location and extent of high concentration regions of OH in surface-impinging diffusion flames.

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The influence of probe laser chirp on hybrid femtosecond/picosecond pure‐rotational coherent anti‐Stokes Raman scattering is studied theoretically and experimentally. Experiments of N2(hybrid fs/ps pure‐rotational coherent anti‐Stokes Raman scattering) are carried out using an in‐house built second harmonic bandwidth compressor, results with different probe chirps of are reported. The experimental spectra are fitted with and without considering probe chirp. Including the chirp improves the fit to experimental spectra at all probe delays. The effect of probe pulse chirp is evaluated through a quantitative analysis of matching residuals.