Interaction Effects in Premixed Turbulent Combustion.
Final rept. 1 Mar 82-30 Sep 85,
CALIFORNIA UNIV SAN DIEGO LA JOLLA
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The research has been concerned with two topics in premixed turbulent combustion. One relates to a continuation of the research on the discovery of new mechanisms for turbulent transport and turbulence generation arising from the interaction of mean force fields due to gradients of either pressure or shear stresses and density variations. These earlier studies consider infinite planar flames and since the mechanisms in question are confined to the flames themselves, the question arises as to their applied significance and importance in determining global features of turbulent flows consisting of two regions of uniform density on each side of a flame. To examine this question we have extended the analysis to provide a unified theory for the description of all three regions. The second topics relates to the consideration of the length and time scales of the temperature field in a premixed turbulent flame. The time history of the temperature at a point within such a flame involves alternately high and low values corresponsing respectively to the passage of products and reactants. By appropriate normalization such a history can be made into a telegraph signal whose statistical characteristics provide information on the time scales of the temperature field. We have shown that an analysis of these characteristics leads to a model for an important quantity in the phenomenology of premixed turbulent combustion, namely the mean rate of chemical reaction.
- Combustion and Ignition