甲烷/氧化亚氮绿色推进剂自着火特性实验及动力学

Nitrous oxide and fuel blend (NOFBX) has been considered as potential hydrazine replacement due to their advantages of non-toxic, high-performance, and low-cost as monopropellant. The methane and nitrous oxide (CH₄/N₂O), a typical NOFBX combination, provides significant benefits for meeting propulsion performances and has become a focus of increased research in recent years. In addition, N₂O and CH₄ can be stored in one premixed tank, which would increase the risk of ignition of premixed fuel and oxidizer at high self-pressurized condition. However, limited data has been published on the ignition safety and ignition delay time (IDT) of CH₄/N₂O at high pressure, resulting in unclear understanding of the ignition hazards and mechanisms. In this work, the ignition behaviors of Ar diluted CH₄/N₂O were experimentally investigated firstly in a heated rapid compression machine (RCM) by detecting the pressure and light emission traces at temperatures and pressures ranging from 1125—1450 K and 10—40 bar. The critical ignition temperature which separates the non-ignition and ignition cases was determined. The results show that the critical ignition temperature decreases with the increases of pressure and fuel/oxidizer concentration. For the successful ignition cases, the ignition delay times were measured and used to validate several recently developed kinetic mechanisms. The results show that the IDT predictions from Yang model have good agreement with the measured IDTs. During the ignition process, CH₄ is mainly consumed by H extraction reaction, while N₂O is mainly consumed by decomposition reaction and reaction N₂O + H=====N₂ + OH.