Performance Characterization of Pellet Catalytic Beds for Hydrogen Peroxide Monopropellant Rockets

Abstract

The present paper illustrates a comprehensive experimental campaign carried out in order to assess the capability of four especially developed catalytic beds to decompose hydrogen peroxide under operational conditions representative of typical application to small monopropellant rocket engines and to characterize the resulting performance of the thruster. The catalytic beds have been integrated in a reconfigurable thruster prototype and tested in a suitable test facility. All beds have shown high decomposition and propulsive efficiencies, well in excess of 90%. In particular, two catalytic beds (indicated as LR-III-106 and CZ-11-600) have been, respectively, able to decompose up to 13 and 11 kg of 90%hydrogen peroxide (equivalent to 433 and 366 g of decomposedH2O2 per gram of catalyst) in 2500 and 2000 s of continuous thruster operation. They exhibited C-star efficiencies higher than 95%. The experimental results have also indicated two main sources of catalyst degradation. In low-porosity catalysts the decay of chemical activity affects the temperature efficiency and causes theflooding of thefirst portion of the catalytic bed,whereas highly porous catalysts experience thermal rupture of the carrier,which leads to excessive growth of the pressure drop across the catalytic bed.