Parametric Study for the Stability Assessment of the Blowdown Propulsion System in Hydrogen Peroxide Blowdown Monopropellant Propulsion System

This investigation focuses on selecting catalyst bed loading (CBL) and catalyst size as key design parameters for blowdown propulsion systems, which has a varying effect by propellant tank volumes, injector orifice diameters, and levels of catalyst activity. The catalytic decomposition process of a high-test peroxide (HTP) monopropellant thruster and the stability assessment of the propulsion system were studied using a reduced-order model of the decomposing process of the reactor. Two simplified models were employed to forecast the reactor’s decomposing process and evaluate system stability across various design iterations. The study demonstrated that combustion instability has a higher tendency to manifest during the intermediate phase of the blowdown procedure, notably when the propellant tank pressure ranges from 14 to 10 bar. The optimal system design was determined through this analysis, with CBL of 90 kg/s/m2 and a catalyst diameter of 1.6 mm. An augmentation in the volume of the propellant tank has been shown to improve the overall stability of the system. Conversely, an enlargement of the injector orifice area is likely to induce instability throughout the design space. Furthermore, the degradation of the catalyst—which is characterized by a slight decrease in the active reaction area—contributes to combustion instability, irrespective of the specific design parameters that have been employed.