Optimization of a Dual-Stepped Cone Inlet for Scramjet Applications

Abstract

This work focuses on optimizing the inlet geometry for a scramjet engine with minimum pressure loss and high diffusion efficiency. Among the proposed configurations, dual-stepped cone configuration is efficient in better pressure recovery at high Mach numbers. The work starts with optimizing the vertical and horizontal distances of the cone, so that the shock intersection happens at the lip of the cowl. The inlet geometry is optimized for 2D wedge and 3D cone. The velocity and pressure contours are plotted, and a comparison is carried out between wedge and cone at Mach 2–7. Static pressure ratio, static temperature ratio, total pressure ratio and adiabatic kinetic energy efficiency are plotted versus flight Mach number which are found with shock angle and flow turning angle. The mass flow rate across the inlet and fuel rate are calculated by the amount of mass and the fuel flow rate with respect to Time and net thrust is calculated with the Thrust relations. Pressure is calculated at arbitrary location downstream of the inlet. Next, two-dimensional computational fluid dynamics simulations are carried out for some inlet geometries that are constructed based on the results of the theoretical analysis using the software. The pressure far-field boundary condition defines the Mach number and static pressure and static temperature of the free stream, the wall boundary condition is applied for the inlet wall. The final data thus obtained is utilized in determining the optimal inlet geometry for the scramjet engine.