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DOI码：10.1016/j.ast.2023.108545

发表刊物：Aerospace Science and Technology

关键字：Velocity nonuniformity，Flame stabilization，Supersonic mixing layer，Active subspace，High-speed flight

摘要：With urgent demand for reliable flame stabilization in air-breathing high-speed aircrafts’ combustors under a wide range of operational scenarios, understanding flame characteristics under various inflow and wall thermal conditions is crucial for mixing layer-stabilized flames. In this paper, the effect of inflow velocity nonuniformity, wall heat loss and their coupling on flame structures, flame lift-off and stabilization mechanisms in the supersonic mixing layer are analyzed. An approach based on the Beta distribution model is innovatively proposed to generate the pseudo nonuniform inflow velocity profile. Different flame modes, the regime diagram and key controlling parameters are quantitatively analyzed via the active subspace method. The results show that the coupling of velocity nonuniformity and wall heat loss can lead to three flame modes, i.e., the heat loss-dominant flame, the intermediate flame, and the nonuniformity-dominant flame, as the flame stabilizes from upstream to downstream regions with the normalized flame lift-off length L^norm in the range of [0, 0.50], (0.50,0.58], and (0.58, 1.0], respectively. This finding is consistent with the autoignition flame stabilization mechanism. In addition, the fuel burnt-out ratio of the flame is found to be nonlinearly correlated with flame lift-off length and peaks approximately with L^norm=0.8, owing to the subtle interactions of mixing and chemical reactions in the mixing layer. The viscous heating in the boundary layer may have a pronounced impact on the flame lift-off depending on the level of wall heat loss, and the predicted L^norm variation could be approximately 26 percent of the combustor length with/without viscous effect under the isothermal wall condition.

论文类型：期刊论文

论文编号：108545

学科门类：工学

卷号：141

页面范围：108545

是否译文：否

发表时间：2023-08-02

收录刊物：SCI

合写作者：An Jian,Zhang Jian,Ren Zhuyin

通讯作者：Wang Nana