Análise numérica do escoamento na seção de captura de ar de um demonstrador scramjet

Abstract

The use of airbreathing propulsion based on supersonic combustion (scramjet technology) is currently seen in the aerospace sector as a promising application in the area of access to space. The main advantages of using this technology compared to current aerospace propulsion systems, are the dispensable of transport of the oxidant, which reduces the vehicle weight, and a relatively greater specific thrust than those conventionally used in rocket engines. Scramjet engines are airbreathing propulsion systems based on no moving parts that use shock waves established on these structures to compress and decelerate the atmospheric air flow, thereby creating thermodynamic conditions suitable for the combustion to occur at supersonic speed in the combustion chamber of the vehicle and providing a subsequent gas expansion and impulse generation. In this work, an analytical and a numerical approach were applied to the design of the air capture section of a scramjet demonstrator and subsequently used in the design of a physical model to demonstrate the technology of supersonic combustion through an atmospheric flight coupled to a rocket at a corresponding velocity of Mach number of 6.8 for a geometric altitude of 30 km. CFD simulations (non-viscous and viscous flow) were performed to verify the flow characteristics on the developed model. The simulations with non-viscous consideration were compared with the results of the analytical theory, presented in this work. The nonviscous flow model was initially used in order to present geometric aspects such the shock wave capture and the aerothermodynamic evaluation, subsequentially the k-kl-omega turbulence model was used for the modeling of the realistic viscous flow and its adequacy due to the appearance of phenomena associated to the interaction of the shock waves with the viscous boundary layer.