关键词: 硝酸羟胺, 催化床结构, 单组元液体火箭发动机, 稳态工作过程, 起动过程, 数值模拟

Abstract: For a HAN-based monopropellant engine, the influence of catalyst bed length and cavity defects on the engine operation process was investigated. Numerical simulations were conducted to investigate the steady-state operation and startup process of a 300N engine using porous media assumption, the Volume of Fluid (VOF) model, and the propellant decomposition model. The research results indicate that increasing the length of the front bed contributes to performance improvement. By increasing the front bed length from 30mm to 40mm, the specific impulse in vacuum is enhanced by 2.7%. However, increasing the length of the front bed leads to a slower response. This not only reduces the pressure and temperature values at the end of the gas filling stage by 7% and 12.5% respectively, but also increases the pressurization time caused by the catalytic bed heating by 33.3%. Cavity defects significantly reduce engine performance. When the front bed length is 40mm, the 5mm cavity reduces the vacuum specific impulse by 15%.

Key words: Hydroxylamine nitrate, Catalytic bed structure, Liquid-monopropellant rocket engine, Stead-state process, Start-up process, Numerical simulation