Self-Ignition of Hydrogen-Hydrocarbons Mixtures in a Hot Supersonic Confined Coflow of Air

The ignition delays of hydrocarbons/hydrogen mixtures in supersonic heated vitiated air flow have been experimentally and numerically studied. A Mach 2 cylindrical jet of cold fuel, is injected in a same Mach number supersonic confined coflow of vitiated air. In order to avoid shock at the exit of the injector, the two flows are adapted in pressure. PLIF images of the flow have been used to understand the structure of the supersonic mixing layer between the oxidizer and the combustible in order to create a physical model of the mixing between the fuel and the air, which is able to predict ignition delays in good agreement with the experiment. For the dierent cases studied, experimental pressure distributions on the walls of the combustion chamber have been used to find, through the way of a one-dimensional analysis of the flow, characteristic parameters, as for example, the Mach number distribution, the temperature distribution in the combustion chamber, or the heat release drop which is useful for the choice of materials for the industrial applications.