A NUMERICAL ANALYSIS OF BOUNDARY-LAYER/SHOCK WAVE INTERACTIONS IN THE COMPRESSION RAMPS OF SCRAMJET INTAKES
Augusto Fontan Moura1; Mauricio Antoniazzi Pinheiro Rosa2
1 University of Queensland - Australia; 2 Instituto de Estudos Avançados - IEAv
doi:10.20906/CPS/COB-2015-0209
Resumo
The Aerothermodynamics and Hypersonics Division (EAH) of the Institute for Advanced Studies (IEAv) is conducting a series of studies aimed at flight demonstration of a hypersonic vehicle prototype powered by a scramjet engine. A scramjet (supersonic combustion ramjet) is a variant of a ramjet airbreathing combustion engine in which the fuel combustion process takes place with the incoming compressed air at supersonic speeds. The scramjet is basically composed of three basic components: a converging inlet, where incoming air is compressed and decelerated; a combustor, where gaseous fuel is burned with atmospheric oxygen to produce heat; and a diverging nozzle, where the heated air is accelerated to produce thrust. The main objective of this work is to study the airflow behavior prior to the inlet of the scramjet engine for the present configuration under investigation (14-XB) of the 14-X hypersonic vehicle prototype. Firstly, a study is presented for the boundary-layer development on the vehicle forebody, which is the first airflow compression region of the scramjet intake system, for different wall boundary conditions and for nominal operating condition (Mach 7 and 30 km altitude) which yields considerably thick boundary-layers. Secondly, a validation study of the transitional viscous flow models and numerical methods available in the ANSYS Fluent code is performed for a simple geometry of a flat plate attached to a compression ramp, in order to evaluate the airflow separation to the wall, near to the ramp, due to boundary-layer/shock wave interactions, by comparison with numerical and experimental data available in the literature. This analysis have shown that the analyzed transitional viscous flow models produced quite good results in simulating flow separation. Finally, a detailed numerical study is performed of the airflow near the walls of the 14-XB vehicle forebody and the scramjet inlet compression ramp for cold and adiabatic wall boundary conditions. Flow separation is observed for both wall conditions a
Palavras-chave: flow separation; hypersonic flow; compression ramp; scramjet