空气动力学学报2025，Vol.43Issue(9)：92-104,13.DOI:10.7638/kqdlxxb-2025.0037
低温环境下当量比对甲烷-氧气预混气爆轰特性的影响机制
Mechanism of equivalence ratio effects on the detonation characteristics of premixed methane-oxygen mixtures under low-temperature conditions
摘要
Abstract
To elucidate the influence of equivalence ratio(φ)on the detonation behaviour of CH4-O2 mixtures under low-temperature conditions,low-temperature detonation experiments were conducted within the temperature range 203.15-283.15 K.Four premixed mixtures with φ=1.0,1.33,1.45 and 1.6 were ignited in a smooth square tube,and the peak pressure as well as the propagation velocity of the detonation wave were recorded.The results show that stable detonation can be established for all equivalence ratios at low temperature and high pressure,whereas no stable detonation is observed at low temperature and low pressure(p=5 kPa).Concerning peak pressure,only considering the cases of successful ignition,the overpressure only increases with φ at lower-temperatures(T=203.15-243.15 K);while a decreasing trend is observed at other temperatures.Compared with the chemical equivalence ratios,the propagation velocity of the high equivalence ratio was reduced,and the velocity loss is significantly increased.The propagation velocity can only reached about 0.9 vCJ after stable propagation,with a maximum deficit of 3.46%.However,the chemical equivalence ratio fails to maintain a stable detonation near the tube exit,whereas the higher equivalence ratios retain their propagation speed and remain stable.Kinetic analysis was performed using CHEMKIN to elucidate the combustion mechanism.It was revealed that the ignition delay increases by up to 2.76×10-4 s as the equivalence ratio increases,and the elementary reaction R73 supersedes R45 in importance.The effect of equivalence ratio on OH radical sensitivity was more significant in the low-temperature environment.Both experimental and numerical results demonstrate that high equivalence ratios can better compensate for the detonation limitations imposed by low temperatures,facilitating the formation of stable detonation.The present study provides fundamental guidance for improving the propulsive performance of detonation engines operating with methane-oxygen propellants under low-temperature conditions.关键词
低温环境/当量比/爆轰波速度/爆轰波压力/化学反应动力学Key words
low-temperature environment/equivalence ratio/detonation wave velocity/detonation wave pressure/chemical reaction kinetics引用本文复制引用
卢宇轩,赵焕娟,刘婧,包颖昕,牛淑贞..低温环境下当量比对甲烷-氧气预混气爆轰特性的影响机制[J].空气动力学学报,2025,43(9):92-104,13.基金项目
国家重点研发计划资助(2022YFC30063) （2022YFC30063）
国家化学安全重点实验室开放课题资助(SKLCS-2024023) （SKLCS-2024023）
跨域飞行交叉技术实验室资助(2024-KFKF-2001) （2024-KFKF-2001）
