2D CFD Analysis of Mach 6 Mixed Compression Scramjet with Hydrogen Combustion

Project Overview

Addressing the challenge of hypersonic airbreathing propulsion, this project focused on the design and analysis of a Mach 6 mixed compression scramjet flowpath. A complete two-dimensional scramjet, including a two-ramp inlet, isolator, step-injected combustor, and nozzle, was designed from first principles using oblique shock theory and optimized with the Oswatitsch criterion. A quasi-one-dimensional cycle model predicted performance, while viscous reacting Computational Fluid Dynamics (CFD) in ANSYS Fluent, employing a density-based RANS solver with the SST k-omega turbulence model and eddy dissipation chemistry, verified the design. Custom MATLAB tools generated structured multiblock meshes. CFD results confirmed the external shock system's agreement with theory but identified a significant shoulder shock boundary layer separation, spilling 30% of capture. It also demonstrated unstart hysteresis for internal contraction and successfully anchored a stable hydrogen flame within the isolator, providing crucial insights for design refinement.