Firing Tests and Simulations of a CubeSat-Scale H2O2-Based Hybrid Rocket

The present work deals with the characterization of high-density polyethylene (HDPE) in a hydrogen-peroxide-based 10-N-scale hybrid rocket. Various tests were successfully conducted, and the propulsive performance was evaluated. Using ballistic reconstruction techniques, a power law of the regression rate depending on the mass flux was obtained. Analytical laws, based on the experiments, were derived to mathematically describe the possible impact of the geometric configuration and pressure on the regression rate. For a more detailed interpretation of the results, the test conditions were simulated by a computational fluid dynamics (CFD) model. It was found that an extended recirculation zone forms, which strongly affects wall heat flux and therefore mass removal and fuel regression. Moreover, it was hypothesized that heat transfer and distribution inside the thruster could have a noteworthy influence on the regression rate, unlike in large-scale engines, where these effects can be safely neglected. Therefore, a parametric analysis of the impact of the aforementioned phenomena was conducted through numerical simulations, showing a very limited impact on the regression rate. In any case, the simulation error is acceptable compared to the experimental results. Finally, thanks to the excellent combustion efficiency shown, the estimation of propulsive parameters under representative space conditions confirmed the potential of the studied engine for small satellite missions.