Performance of hydrogen peroxide decomposition in a preheated monopropellant thruster catalyst chamber

Preheated conditions in monopropellant thrusters are known to enhance propellant decomposition efficiency. This study examines the performance of a hydrogen peroxide (H₂O₂) monopropellant thruster under various preheated conditions. Pressure and temperature measurements within the catalyst chamber, which correlate with decomposition efficiency and propulsion performance, were experimentally investigated. Resistive heaters were installed on the outer surface of the monopropellant thruster chamber, which was filled with manganese oxides for firing tests under different initial temperature conditions. The resistive heaters adjusted the initial chamber temperature within the range of 28 °C to 237 °C. The 10 N class H₂O₂ thruster demonstrated varying performance with characteristic velocity efficiencies, used in this study as an indicator of overall decomposition efficiency, ranging from 64 to 89 %. It was observed that the efficiency initially increased with increasing preheated temperature, reached a maximum of 89 % at 106 °C, and then began to decrease, indicating the existence of an optimal preheating condition for maximising efficiency. The experimental results showed that higher preheated chamber temperatures contribute to improved propellant decomposition efficiency. However, this does not always guarantee the highest efficiency due to additional pressure losses caused by the downstream catalyst, particularly when the propellant is sufficiently decomposed in the upstream catalyst chamber. The findings also suggest that the residence time of the propellant within the chamber could be a critical parameter for optimising monopropellant catalyst chamber performance, especially in the analysis of propellant decomposition. These results provide valuable insights for improving monopropellant performance through preheating, catalyst optimisation, and decomposition analysis.