Numerical Simulations of Paraffin–Oxygen Hybrid Rocket Engines With Axial and Vortex Injectors

This work presents computational fluid dynamics simulations of a paraffin–oxygen hybrid rocket engine, based on experimental firing tests from the HYPROB program. RANS simulations, with detailed submodels coupling combustion, convective and radiative heat transfer, and fuel regression, are employed to analyze the internal ballistics of a 1000~N-class demonstrator operating with two different oxidizer injector types: a conventional axial injector and a swirl injector. Aside from the injection pattern, the tests share similar operating conditions. The study aims to support the interpretation of experimental data and to refine the predictive capabilities of numerical models for hybrid rocket propulsion.