Abstract: In order to study the effect of plasma torch jet frequency on the supersonic combustion characteristics，experiment of plasma torch ignition and assisted combustion characteristics in supersonic airflow was carried out. As the condition of?single jet energy remains constant，the plasma torch jet frequency presents two kinds of state，and the supersonic combustion characteristic also shows two different combustion modes. Combustion mode transition process is accompanied by the regular reflection to Mach reflection transformation process. The conclusions obtained are that if combustor operates in subsonic combustion mode the plasma torch has no effect on combustion，while combustor operates in early supersonic combstion mode the plasma torch can prompt the combustion mode transition from the early supersonic combustion mode to the subsonic combustion mode.

Key words: Plasma torch；Jet frequency；Supersonic combustion；Mode transition

摘要： 为了研究等离子体火炬喷射频率对超声速燃烧特性的影响，采用实验方法研究了超声速气流中等离子体火炬的点火及助燃特性。在单次喷射能量保持不变的情况下等离子体火炬喷射频率呈现两种不同状态，使得超声速燃烧特性也呈现出两种截然不同的燃烧模态。燃烧模态转捩过程中伴随有正规反射向马赫反射的转化过程。等离子体火炬对处于亚燃模态的燃烧场不起作用，对处于早期超燃模态的燃烧场产生燃烧促进作用，并可以促发燃烧场由早期超燃模态向亚燃模态的转捩。

关键词: 等离子体火炬; 喷射频率; 超声速燃烧; 模态转捩