Investigation of Flow Structure, Mixing and Chemical Reaction in Combusting Turbulent Flows.

摘要

An experimental investigation of the relationship between flow structure and flame structure in a low-speed, co-flowing, non-premixed, methane-air jet diffusion flame has been completed. The purpose of the research was to examine the spatial structure of the unsteady reaction process as it relates to the unsteady velocity field and to use topological methods in the interpretation of flame dynamics. A small, acoustically produced, perturbation in the fuel jet velocity was used to phaselock the basic flickering instability of the flame thus creating a very periodic and controllable flow, suitable for conditional sampling. Various diagnostic techniques were used in the research including single-component laser anemometry, direct and schlieren photography, Mie scattering from seed particles introduced into the flow, planar, laser-induced fluorescence the OH radical and particle tracking for measuring instantaneous planar velocity field data. Velocity fields have been measured as a function of the phase of the flickering cycle over the first 20 diameters of the flame. (KR)