Structural impact of honeycomb catalysts on hydrogen peroxide decomposition for micro propulsion

Hydrogen peroxide is under investigation with regard to its potential to replace the presently used highly toxic rocket propellants NTO and MON-3. Catalytically decomposed hydrogen peroxide results in a steam–oxygen mixture at elevated temperature and can be used either as a monopropellant or as an oxidizer in a bipropellant system. To guide the monolith catalyst design, a lumped parameter model of the decomposition implemented into a numerical thermal model has been developed. The one dimensional flow model includes decomposition and is coupled to a finite element structural domain of the decomposition chamber and catalyst to investigate the impact of the catalyst and the chamber structure on the decomposition behavior. Special focus is laid on the transitional behavior of hydrogen peroxide conversion to facilitate immediate start-up of the thruster system after valve opening command. The numerical results have been validated with experimental data. Major findings of the model such as the existence of a radial temperature gradient across the catalyst have been experimentally validated. The presented theoretical method predicted a strong impact of structural mass capacities of catalyst and decomposition chamber on the transient decomposition performance. This prediction has shown to be in good correlation with the experimental results.

► Presenting a simulation of the interaction of structural thermal mass of catalyst on decomposition performance for a honeycomb catalyst.
► Simulation of the transient behavior of decomposition and experimental verification.
► Experimental and theoretical discussion of the impact of thermal mass of decomposition chamber on catalyst performance.
► Experimental measurement of radial exhaust temperature gradient downstream of the catalyst and discussion of this phenomenon.