Innovative 3D numerical study of a catalyst bed and comparison with previous 2D and experimental studies

Abstract

This paper analyzes the catalytic bed of a 10 (N) Liquid Monopropellant Thruster (LMT) in an innovative 3D numerical study. LMT includes an injector, a decomposition chamber with a catalytic bed, and a nozzle. Injectors spray Liquid propellant onto the catalytic bed (decomposition chamber). The catalyst bed decomposes the liquid propellant through thermal and chemical reactions, and the gases generated at high temperatures and pressures flow through the nozzle to create thrust force. In this thruster, liquid hydrazine is used as the monopropellant and the catalytic bed consists of iridium-coated alumina pellets (Ir/Al₂O₃) in the decomposition chamber. Catalytic and thermal reactions are modeled by calculating reaction rates using Arrhenius relationships. The results that were obtained were evaluated and compared with experimental tests and 2D numerical studies (the porous medium hypothesis and the 2D modeling of the catalyst pellets). This evaluation demonstrates the obtained results are more accurate and closely aligned with the experimental results.