Estudo conceitual de um demonstrador scramjet de admissão interna com três rampas

Abstract

In this work, a conceptual study of an airbreathing propulsion system based on supersonic combustion (scramjet technology) of an aerospace vehicle flying at hypersonic speed of 2050 m/s at an altitude of 30 km was developed. The objective was to study a symmetrical internal configuration with three ramps in the compression section and compare it with the mixed external and internal configuration with three ramps and same turning angles. An analytical theoretical methodology (engineering approach) was applied using the oblique shock wave theory in the compression section, the Rayleigh theory of heat addition in one-dimensional flow, with constant area cross section, not considering fuel mass, in the combustion chamber, and the area ratio theory coupled with the PrandtlMeyer expansion theory in the expansion section. The flow properties without fuel injection at the combustion chamber (power-off) and with hydrogen fuel injection and burning at supersonic speed (power-on) were analyzed. The atmospheric air captured by the inlet of the scramjet vehicle is compressed and decelerated to a condition of supersonic speed and a temperature higher than the spontaneous ignition temperature of the fuel. Considering power-off condition, the flow at the expansion section obtained a velocity lower than the flight speed, due to the increase in entropy. However, in the power-on condition, the combustion products of the atmospheric air-hydrogen fuel mixture provide an increase in the scramjet's flight speed, producing uninstalled thrust of 402.64N and specific impulse of 4164.02s. Finally, a performance analysis of the scramjet developed was carried out considering parameters such as propulsive efficiency, thermal efficiency and global efficiency.