Análise conceitual de um demonstrador scramjet de admissão interna

Abstract

The objective of this work was to apply analytical and numerical modeling to develop a conceptual design of an aerospace vehicle that uses an airbreathing propulsion system based on supersonic combustion (scramjet technology), for flight at hypersonic speeds, in the Earth's dense atmosphere. An internal intake configuration was used, with a single ramp, mirrored by the line of symmetry, which establish oblique shock waves incident on the leading edge at the intersection of the incident shock waves, and three oblique reflected shock waves that converge on the entrance to the combustion chamber. Upon contact with the ramp, the hypersonic flow establishes an incident oblique shock wave and three reflected shock waves, which alter the properties of the flow. In the analytical study are applied: the oblique shock wave theory in the compression section; the theory (Rayleigh) of heat addition in one-dimensional flow, considering constant cross-sectional area and without considering the addition of fuel mass, in the combustion chamber section; and the area ratio theory coupled with the Prandtl-Meyer expansion theory, in the expansion section. Numerical simulation was carried out using the Fluent module of the ANSYS software under the same conditions as the analytical study, considering air as a perfect gas and without the boundary layer. There was excellent agreement between the analytical and numerical results. The choice of the compression ramp angle used provided the on-lip and on corner shock conditions in the compression section. Also, the angle of the compression ramp generated the conditions of velocity (Mach number) and temperature of the flow, of atmospheric air at the entrance of the combustion chamber, sufficient for mixing and spontaneous burning of hydrogen at supersonic speed. Finally, the conceptual design of the scramjet with internal intake configuration, with a compression ramp resulted in the velocity of the gases from the combustion products superior to the flight velocity, evidencing the generation of non-installed thrust.