Investigation of high-speed ramjet engines

This paper gives a brief overview of investigations and developments of combustion chambers of high-speed ramjet engines performed at Moscow Aviation Institute (MAI). Shadow photographs are given which show changes in the structure of regular shocks versus heat input to the flow during hydrogen combustion. The impact of oblique shock waves on combustion is studied by visualizing OH radical luminescence. Because of the significant dependence of the combustion effectiveness on the flow parameters and structure, it is relevant to study ramjet engine designs with a variable air flow duct of the combustion chamber, which allows adjustment of the working section to obtain the required parameters and characteristics over a wide range of flight conditions. A large series of tests of such combustion chambers have been performed under a joint French–Russian program. Measurement results corresponding to flight Mach numbers 2–7 are given. Mixtures of chemically pure methane and hydrogen was used as fuel. Characteristics of a three-stage heater of model flow developed at MAI for testing wide-range combustion chambers are presented.