Liquefying fuel regression rate modeling in hybrid propulsion

This paper presents an overview of the main hypotheses and equations which lead to the design of the Hydres platform, a 1D code developed to evaluate liquefying fuel regression rates in hybrid propulsion and the engine propulsive performances. This code is based on an integral description of the aerothermochemical flow coupled to a one equation model for the liquid film. The validation of this numerical code was performed thanks to the Hycom facility, a lab-scale hybrid engine instrumented, among others, with ultrasonic sensors to follow the ablation of the fuel grain and hence its instantaneous regression rate. Measurements performed during the hybrid engine firing tests also provide the instantaneous regression law of the oxidizer/fuel pair and experimentally highlight the existence of a regression rate limit.