Turbulence/Premixed-Flame Interactions in Isotropic Turbulence

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The influence of preferential diffusion of reactant species on the propagation of a flame through a turbulent gaseous fuel/oxidizer mixture is to be studied by a series of experiments in a constant volume, fan-stirred combustion chamber. The velocity field and turbulence quantities will be measured using two-point laser velocimetry and particle-image velocimetry, and laser flame tomography will be used to determine the instantaneous flame surface. Hydrogen/oxygen/nitrogen mixtures producing preferential diffusion with a stabilizing influence on the flame structure will be chosen to cover a wide range of laminar flame speeds, and the turbulence intensity and integral scale of the reactants will be controlled independently. The test range will involve the thin laminar flamelet regime for turbulent Reynolds numbers up to 10,000. The flame propagation process will be simulated theoretically using statistical time-series techniques as a way to interpret the measurements, and as a way to initiate the development of a computationally tractable predictive tool which includes a rational treatment of the flow physics. Understanding the interaction between turbulence and the speed with which a flame propagates into a combustible mixture is a fundamental issue in combustion science. The results of this research will provide insight into one aspect of this complex phenomena, with applications possible to internal combustion engines and turbulent premixed combustion processes in general.