Flame-Vortex Interaction in Laminar Gaseous and Spray Diffusion Flames

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ABSTRACTALESSANDRO GOMEZCTS-9904296This is an experimental and computational investigation of the interaction of laminar counterflow gaseous and spray diffusion flames with laminar vortices. Several laser diagnostic techniques are applied, including two-component phase Doppler interferometriy to measure gas and droplet velocities and the droplet size distribution; Stokes/antiStokes Raman scattering to obtain gas-phase temperature; line Raman scattering to measure the concentrations of major species and to determine the mixture fractions; and planar laser-induced fluorescence of formaldehyde (CH2O), hydroxyl (OH), and methyne (CH) to monitor flame response to the vortex-induced perturbation. When feasible, these techniques are phase-locked to the arrival of the vortex. Computationally, the gas phase is modeled using an Eulerian formulation and the droplet phase is modeled using a Lagrangian formulation; the model includes detailed transport and chemical kinetics and size distribution effects. The emphasis is on methanol and heptane flames with the fuel supplied either as a spray or in vapor form. The approach is intended to provide an understanding of the flame-vortex interaction, including the effects of time dependence and curvature on flame structure , extinction and re-ignition behavior, and pollutant formation.