H2/RP-3航空煤油混合燃料着火特性研究

实现碳氢燃料的快速点火与稳定燃烧是超燃冲压发动机研制过程中必须解决的关键问题。在航空煤油中添加乙醇燃料,利用乙醇热分解得到氢气等可燃小分子气体来改善燃烧过程是达到促进航空煤油着火与燃烧稳定的有效手段。选取正癸烷、甲苯、丙基环己烷三组份混合燃料作为RP-3航空煤油的模拟替代燃料,构建了其燃烧反应机理;并对该机理进行了验证。为揭示氢气对RP-3航空煤油着火特性的影响,构建了RP-3航空煤油/氢气混合燃料的燃烧反应机理;并对该机理进行了验证。同时,采用该燃烧反应机理分析了多工况下掺氢比对RP-3航空煤油着火特性的影响。结果表明,采用正癸烷、甲苯、丙基环己烷三组份混合燃料的燃烧反应机理计算得到的着火延迟时间与相应工况下RP-3航空煤油着火延迟时间的试验数据吻合良好;多工况下氢气添加能够提升RP-3航空煤油/氢气混合气活性,缩短着火延迟时间,促进燃料着火;同时,随着混合气中掺氢比的升高,混合气的着火延迟时间逐渐缩短。

Study on ignition characteristics of H2/RP-3 kerosene mixed fuel

Realizing fast ignition and stable combustion of the hydrocarbon fuel is the key problem during the development process of scramjet engine. Adding ethanol fuel into the kerosene and using the small molecular hydrogen which is decomposed from ethanol to improve the combustion process is an effective way to realize the fast ignition and stable combustion. In this paper, a surrogate fuel includes n-decane, toluene and propyl cyclohexane was selected for RP-3 kerosene and the combustion reaction mechanism of this surrogate fuel was formed and validated. In order to illuminate the effects of hydrogen addition on the ignition characteristics of RP-3 kerosene, the combustion reaction mechanism of RP-3 kerosene/hydrogen was formed and validated. At the same time, the effects of hydrogen fraction on the ignition characteristics of RP-3 kerosene under various conditions were analyzed using this mechanism. The results show that the simulated ignition delay times of the surrogate fuel which consists of n-decane, toluene and propyl cyclohexane using this mechanism are agreed well with the corresponding experimental data of RP-3 kerosene. With hydrogen adding, the activity of RP-3 kerosene/hydrogen mixture can be improved, the ignition delay time is shortened and the ignition is promoted under various conditions. Furthermore, with the increase of hydrogen fraction in mixture, the ignition delay time of the mixture is shortening.