Scramjet Design Research Articles

Numerical Study of Hypervelocity Flows Through a Scramjet Combustor

Results are reported from a numerical investigation of mixing and combustion of hydrogen injected into an airstream at high enthalpy (e ight Mach number 17 ). Numerical computations performed using the general aerodynamic simulation program code are compared with experimental data obtained with a rectangular combustor model in the free-piston driven, ree ected-shock tunnel facility T5, at the Graduate Aeronautical Laboratories at the California Institute of Technology. Computed results show good agreement with the measured static wall pressures. Mixing performance with the injection of hot hydrogen is shown to be in line with established correlations for scramjet design. Also, the issue of spatial uniformity of the hydrogen ‐ air mixture has been explored.

Numerical Solution for Perpendicular Sonic Hydrogen Injection into a Ducted Supersonic Airstream

This note discusses a computer program being developed to study the flow field near opposing perpendicular fuel injectors in scramjets. The MacCormack time-split, finite difference relaxation technique was used to solve the full two-dimensional compressible Navier-Stokes equations along with energy and species equations. By using this technique, a program was developed to consider the turbulent nonreacting flow of hydrogen and air in a rectangular duct. A damping term, proportional to the second derivative of pressure and temperature, was used to produce a stable solution behind the hydrogen jet in the neighborhood of the recompression shock. A case using actual conditions encountered in current scramjet design was analyzed, with results agreeing qualitatively with experimental observations.