Design and optimization of a small scale solid fuel ramjet

This paper presents the design and optimization of a small scale solid fuel ramjet (SFRJ) intended for testing at Mach 3.5 within a 30 cm-diameter test section of a supersonic wind tunnel. The design process begins with the optimization of a two-dimensional air intake, consisting of an external compression surface with multiple ramps. The ramp angles are calculated to achieve efficient compression while minimizing total pressure losses. To quantitatively assess the intake performance, a novel efficiency parameter is introduced, incorporating both total pressure losses and drag augmentation contribution. The optimized intake design is validated through Computational Fluid Dynamics (CFD) simulations to ensure accurate flowfield predictions. Building on the optimized intake, the combustion chamber is designed as a 2D configuration, incorporating a HTPB solid fuel. Finally, the overall ramjet design, including the intake, combustion chamber, and nozzle, is analyzed through CFD simulations under both cold-flow and reactive flow conditions. Aerodynamic performance and operational feasibility of the proposed design have been indeed validated showing promising performance for future high speed flight applications.