Study the Performance of Monopropellant Thruster Catalysts with Different Iridium Loading

In this paper, the effects of different weight percentage of iridium (Ir) nanoparticles loadings on performance parameters of hydrazine catalyst and monopropellant thruster have been studied. Nanoparticles of iridium with different contents of 10 wt%, 20 wt%, and 30 wt% has been coated on gamma-alumina of 1 to 2 mm size for decomposition of hydrazine during some various steps of calcination. These catalysts then have been tested in a 1 N thruster. The tests were conducted with a scenario of different stages of steady and pulsating fires of different times and duty cycles. Test results showed that catalyst loss was minimum with 30 wt% of iridium nanoparticles loading. Despite of this, there were no meaningful difference between other parameters such as pressure roughness, thrust, specific impulse, and catalyst crushing. The results showed a good value of characteristic velocity. All parameter values of three type of catalysts were within desired range.