Design of the feed system of a Hybrid Rocket Engine

Over the last decade, space industry has experienced a radical change with the apparition of private companies providing low-cost solutions for nanosatellites launch and civil suborbital flights. In this context, Hybrid Rocket Engine (HRE) technology seems to meet safety and cost-efficiency requirements compared to widely used solid and liquid propulsion systems. From a general point of view, the design of such engine is not straightforward because of its intrinsic transient behavior, i.e., combustion chamber geometry continuously varies with the operating time [1]. In addition, combustion process can be highly unstable because of the potential coupling of turbulent multiphase reacting flow and acoustic modes of the chamber [2]. In practice, such interactions may result in low-frequency instabilities, damage the payload and lead to a partial destruction of the HRE.