Abstract
Hypersonic propulsion systems operate in a regime where compressibility, shock–turbulence interactions, aerodynamic heating, combustion, transport phenomena, and thermochemical effects are strongly coupled. In scramjets, rotating detonation engines (RDEs), and related high-speed propulsion concepts, preliminary design requires tools capable of capturing the dominant gas-dynamic and thermochemical mechanisms at a fraction of the cost of high-fidelity multidimensional simulations. Combustion Toolbox (CT) is an open-source MATLAB framework, with graphical and command-line interfaces, originally developed for chemical-equilibrium calculations and later extended to shock, detonation, and propulsion applications. Here, we present recent and ongoing developments that expand the object-oriented CT ecosystem into a unified framework for high-speed reactive-flow modeling. First, CT now includes tools for scramjet compression-system design and internal-flow analysis. Inlet optimization is formulated as an oblique-shock problem in which multi-ramp geometries are obtained by maximizing total-pressure recovery subject to prescribed exit conditions. The approach extends beyond calorically perfect gases through efficient thermochemical-equilibrium calculations. In parallel, CT incorporates a quasi-one-dimensional solver for internal-flow calculations in isolators, combustors, and nozzles, accounting for variable-area effects, wall losses, fuel injection, mixing models, and finite-rate chemistry. Second, the CT shock-and-detonation solver has been extended with new wave-solution families, including Prandtl-Meyer expansions for multiple caloric models. These elements are being combined through compatibility conditions to construct multi-region wave-network solutions relevant to high-speed propulsion systems, including RDEs. Third, CT now includes CT-LIA, a linear interaction analysis module for quantifying turbulence amplification across shock waves in multi-component reactive mixtures. The model applies to inert and reactive shocks under different upstream perturbation modes and has recently been extended to non-ideal equations of state under frozen composition. These developments establish CT as a modular framework for high-speed reactive-flow analysis.
