An improved study of the uniformity of laminar premixed flames using laser absorption spectroscopy and CFD simulation.

• Uniformity of laminar premixed flames is comprehensively studied. • Thermochemical structures are obtained by LAS measurements and CFD simulations. • Almost identical radial distribution of temperature and major products are observed. • Central H 2 O/CO 2 concentrations remain constant with varied Q coflow and Re reactant. • Flame uniformity is insensitive to Φ, but more sensitive to Q coflow and Re reactant. We performed a combined experimental and numerical study of the flame uniformity for a standard McKenna burner by investigating the spatially-resolved temperature and species concentrations in laminar CH 4 /air premixed flames. In the experiment, multi-wavelength laser absorption spectroscopy (LAS) was employed for in situ , non-intrusive, and quantitative measurements of temperature, H 2 O and CO 2. In the simulation, computational fluid dynamics (CFD) simulations were performed to model the thermochemical structures of the flames. The LAS measurements and CFD simulations were compared by varying the co-flow rate, equivalence ratio (Φ = 0.8–1.2), and the Reynolds number of the reactant flow. In general, all the simulations were in relatively good agreement with the experimental data. We observed that the flame temperature and H 2 O/CO 2 concentrations have almost the identical radial distributions with a certain non-uniformity, which should be carefully considered when using the standard flame for combustion research. In particular, the flame uniformity could be improved by increasing the Reynolds number of reactant flow or reducing the co-flow rate. [ABSTRACT FROM AUTHOR]