在CI引擎相关条件下,汽油类燃料的层状预混合火焰的结构特征
Yuanyuan Zhao1, Zongyu Yue1, Yan Zhang2,3
1State Key Laboratory of Engines, Tianjin University, Tianjin 300350, PR China.
ACS omega
|June 24, 2024
概括
这项研究从数值上研究了汽油压缩点火的火焰,揭示了高温在脱火转为自燃过渡后改变了燃烧行为. 关键反应发生变化,特定的进度变量有效区分分层混合物中的火焰传播模式.
科学领域:
- 燃烧科学与工程 燃烧科学与工程
- 化学动力学和热力学.
- 计算流体动力学的流体动力学.
背景情况:
- 汽油压缩点火 (GCI) 由于部分预混合条件和长时间的点火延迟,表现出复杂的火焰结构 (消火,自燃).
- 了解GCI火焰传播对于优化发动机性能和减少排放至关重要.
研究的目的:
- 在GCI相关条件下,对PRF90/空气混合物的火焰结构和传播特征进行数值研究.
- 分析未燃烧的混合物特性,停留时间和温度对火焰行为和过渡的影响.
- 确定主要的化学反应,并评估区分燃烧模式的标准.
主要方法:
- 在发动机相关条件下的PRF90/空气混合物的数值模拟.
- 灵敏度分析,以确定在不同燃烧模式下存在的主导链分支反应.
- 化学爆炸模式分析使用交叉进度变量 (C0和) 来分析局部燃烧模式.
主要成果:
- 火焰传播速度取决于未燃烧的属性和停留时间;政权过渡仅取决于停留时间.
- 高的未燃烧温度会导致不同的燃烧行为,从自燃过渡到自燃过渡.
- 主要反应因温度而异: H + O2 = OH + O 和 CO + OH = CO2 + H 在防火过程中; H2O2 (((+M) = 2OH (((+M)) 和自燃辅助火焰中的燃料氧化反应.
结论:
- 和C0都可作为火焰位置来区分传播模式,但它们对等效率的敏感性不同,影响了分层混合物分析.
- 基于C0的火焰位置在φ=1.0提供了更全面的反映层级预混合GCI中火焰的发展.
- 了解这些反应途径和传播标准对于控制GCI燃烧过程至关重要.
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