Nozzle throat erosion in hybrid rocket engines is generally more emphasized than in solid rockets due to a greater concentration of oxidizing species in the combustion products. Therefore, its accu...

We have performed high-order compressible Navier–Stokes simulations of a thermoacoustically unstable resonator employing , the increase of the acoustic power produced, but also of the heat input required, for thermodynamic conditions approaching the critical point. Finally, intense mass transport events at transcritical conditions are shown to entail thermodynamic and convective nonlinearities, which do not, however, govern the limit cycle physics, dominated instead by nonlinear minor losses.

This paper investigates the use of neural networks as surrogate models for fast and accurate performance prediction of hybrid rocket engines (HREs). To this aim, a deep feedforward neural network i...

Nozzle erosion predictions are fundamental to increase the technology readiness level of hybrid rocket engines. In this work, Reynolds-averaged Navier–Stokes simulations of the internal ballistics ...

Hybrid rockets are considered a promising future propulsion alternative for specific applications to solid or liquid rockets. In order to raise their technology readiness level, it is important to perform predictive numerical simulations of their internal ballistics. The objective of this work is to describe and validate a numerical approach based on Reynolds-averaged Navier–Stokes simulations with sub-models for fluid–surface interaction, radiation, chemistry, and turbulence. Particular attention is given to scale effects by considering two different paraffin–oxygen hybrid rocket engines and a simplified grain evolution approach from the initial to the final port diameter. Moreover, a mild sensitivity of the computed regression rate to paraffin’s melting temperature, surface radiation emissivity, and Schmidt numbers is observed. Results highlight the increasing importance of radiation effects at larger scales and pressures. A numerical rebuilding of regression rate and pressure is obtained with simulations at the time-space-averaged port diameter, producing a reasonable agreement with the available experimental data, but a noticeable improvement is obtained by considering the grain evolution in time.