An Aero-Propulsive Model of the Technological Demonstrator Scramjet 14-X S: Preliminary Results
Sebastião de Carvalho Netto1; Paulo Gilberto de Paula Toro2; Marco Antônio Sala Minnuci2; Israel da Silveira Rego2
1 ITA; 2 IEAv
doi:10.20906/CPS/CON-2016-0759
Resumo
Scramjets represents the last frontier in aeronautical high-speed engines. The Aerothermodynamics and Hypersonics laboratory Prof. Henry T. Nagamatsu at the Institute for Advanced Studies (IEAv), is carrying out research and development of technological demonstrators of hypersonic airbreathing propulsion based on supersonic combustion. One of them is the scramjet 14-X S that will be tested in flight at 30 km altitude and speed equivalent to Mach 7, as an airbreathing third-stage rocket engine for access to space. The 14-X S scramjet is an engine with planar symmetry, where each half has two compression ramps (inlet), a combustion chamber (combustor) and two expansion surfaces (nozzle) for thrust generation. This article presents ananalytical model for the determination of the aerodynamics forces (drag & lift) and the propulsive force (thrust) that act on the 14-X S in atmospheric hypersonic flight. The aero-propulsive model proposed herein considers air as a calorically perfect gas, standard atmosphere for freestream, shock wave theory to determine the angle of the shocks generated by the inlet of the 14-X S and the properties through them, theory of Rayleigh to estimate the heat addition from combustion reaction between supersonic stream of air and hydrogen in the combustor, isentropic expansion theory (area ratio) to calculate the properties of the exhaustion through confined regions, Prandtl-Meyer theory to obtain the airflow properties through centered expansion waves, and finally thrust calculation. The effect of viscosity was considered by changing the geometry of the inlet and the nozzle of 14-X S, and thereby, the shock and expansion angles, while the friction was determined from Van Driest solutions for laminar flow. The preliminary calculation shows the following results: The pressure drag is maximum on the second compression ramp of the 14-X S; the friction is more pronounced along the first expansion section; the 14-X S main body creates more drag than its cowl; the overall wave drag on the 14-X S fli
Palavras-chave: Scramjet; aerodynamic loads; thrust; hypersonic; flight test