TURBULENT MIXING AND BURNING OF COAXIAL STREAMS INSIDE A DUCT OF ARBITRARY SHAPE
ARO INC ARNOLD AFS TN
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A theoretical investigation of the ducted turbulent mixing of coaxial streams is presented. The effects of equilibrium chemical reactions in the mixing layer are included in the analysis. In Part I, the theory is developed for ducted mixing systems in which the inviscid portions of the flow are assumed to be one-dimensional. The integral method is used, and the mixing zone velocity profiles are assumed to be similar. Turbulent Prandtl and Lewis numbers are assumed to be unity, and the turbulent shear stress along one control surface in the mixing layer is computed by use of a semi-empirical model for the eddy viscosity. The theory is formulated to include the downstream regime where the mixing layer extends across the entire duct. The system of integral equations is transformed into a form suitable for numerical solution by standard methods. In Part II, the theory is extended to include the influence of a nonuniform supersonic inviscid core flow. A technique is developed for coupling the numerical solution of the inviscid core flow from the method of characteristics with the solution of the integral equations for the mixing layer. The theory is correlated with low speed experiments, with supersonic air-air ejector experiments and with experiments on ducted rocket-air mixing. The correlations show that the theory gives satisfactory results for the performance of ducted rocket-air mixing systems which are representative of air augmented rockets.
- Fluid Mechanics
- Combustion and Ignition