A Transient, Multi-Scale, Heterogeneous Model of Hydrogen Peroxide Decomposition for 3D-Printed Catalysts

Abstract

Hydrogen peroxide thrusters rely on catalysts to generate steam and oxygen, and yet relatively little is known about the processes that occur within the catalyst bed. Previous models have assumed that both diffusional resistances and temperature differences between the catalyst and the fluid can be ignored. In this paper a 1D, multi-scale, transient, heterogeneous and diffusion-enabled model of catalytic hydrogen peroxide decomposition was developed and applied to a 3D-printed catalyst bed, which offer potentially significant benefits over conventional silver mesh catalysts. A triply periodic minimal surface (TPMS) was the chosen geometry. Simulation results suggests that the heterogeneous and diffusion-limited nature of the reaction cannot be ignored if accurate predictions about the catalyst bed performance are to be made. Through the newfound capabilities of the present model, the influence of various parameters such as the hydrogen peroxide concentration, pressure, geometric unit cell size, bed void fraction and support material were characterized. Increasing the concentration, decreasing the unit cell size and increasing the void fraction are all effective strategies for improving the performance of hydrogen peroxide thrusters, made possible by new catalytic materials and the advent of 3D-printing.