A two-dimensional hypersonic inlet model that displays self-beginning/self-starting characteristics is designed with various level of choking proportions at a freestream Mach number of M∞ = 6, without the use of variable geometry in order to find an optimal 2D geometry for Mach 6. An introduction of scramjet engine as well as its primary component, the inlet, is given in the beginning. The configuration of scramjet intake geometry consisting of two exterior compression ramps, followed by a subsequent inlet and interior isolator, is chosen. The flow conditions are incoming Mach 6 with free-stream temperature of T∞ = 226.65K and Free stream Pressure of P∞ = 1171.87 Pa is considered with respect to the operating altitude of 30,000 Meters. Consequently, oblique shock wave will be formed and its interaction with viscous boundary layers will lead to flow separation that is responsible for the loss of mass flow, total pressure and several other effects. Next, 2D CFD simulations are carried out for same inlet geometries that are constructed based on the results of the theoretical analysis using the K-Omega SST turbulence model in Fluent. As expected, due to the presence of throttling plug, the mass flow rate inside the inlet tends to oscillate front and back with increase in TR, which leads to the unstart condition of the designed inlet. Lastly, the conclusion of design process is shown graphically and the steady, unsteady flow conditions are shown using a simplified frequency f parameter.

Keywords : Hypersonic Inlet, Steady, Transient, Shock Waves, Mach Number