Transient combustion phenomena in high-speed flows in ducts

The problem of combustion stabilization in a duct with supersonic flow at the entrance is studied by means of numerical simulation, with the use of experimental data if available. The influence of the transient process of combustion development on the final flow structure is demonstrated. Four examples are considered and analyzed: oscillations of a pseudoshock with combustion in an asymmetric duct under asymmetric heat exchange conditions, hysteresis of flow in a model combustor of a high-speed civil aircraft engine, various ways of flame stabilization in a model high-speed combustor with a step, and formation of asymmetric flow structures in a symmetric high-speed combustor. These examples include cases with a stationary final state, with periodic oscillations, and with flameout. Influence of the kinetic mechanism, of the wall heat exchange, and of the flow symmetry is shown. Physical mechanisms of combustion stabilization in high-speed flow are analyzed. The possibility of multiple solutions with stabilized heat release is demonstrated for the considered class of flows.