Reaction Zone Characterization in a Gas Turbine Model Validation Combustor

The Enclosed Sydney Swirl Burner (ESSB), a half-scale version of the Sydney Swirl Burner coupled to an optically accessible combustion chamber, was recently constructed at the National Energy Technology Laboratory for the purpose of generating global emissions and model validation data in a configuration relevant to industrial and gas turbine combustion. The ESSB is capable of diffusion flame combustion of CH₄/H₂/inert fuel mixtures in highly swirling air flow over a bluff body, and can produce a wide variety of flame types and structures for study. Based on stability characteristics and global emissions data, three flames were chosen for reaction zone characterization: a non-swirling 1:1 H₂:CH₄ flame, a high-swirl 1:1 H₂:CH₄ flame, and a lifted, V-shaped flame of CH₄ with a swirling air flow. Reaction zone characterization is performed via planar OH-PLIF measurements taken at multiple locations within the square cross-section of the ESSB. Mean flame surface locations are described, and maps of flame front probabilities are generated for each of the flames. Measurements indicate quenching in the high strain region in the neck above the bluff body for the non-swirling flame, wall-quenching for the swirling flames, and OH production below the lifted flame that helps sustain the reaction zone. The OH-PLIF data, as well as global emissions and thermal boundary condition measurements for these flames, are freely available for model validation purposes.