Abstract: Low pressure is an adverse condition for combustion. On the basis of chemical dynamics, decreasing pressure leads to decreasing density of air and decreasing rate of chemical reaction. Experiments in a ram jet prototype combustor were carried out. The results demonstrated that while the inlet pressure of the combustor p_in varied from 0.094 to 0.065MPa, the combustion efficiency decreased; when the pressure p_in decreased to 0.065MPa, the combustor performance deteriorated rapidly, and the combustion became so unsteady that the fire could quench anytime with the fluctuations of pressure or fuel/ air parameters. The qualitative characteristics of combustion efficiency with pressure were the same whether there was a flame-passing gutter or not, however, the combustion efficiency was lower when there was not.

Key words: Combustion chamber; Ramjet engine; Low pressure

摘要： 低压不利于燃烧,从化学动力学角度分析,压力降低导致空气密度降低,化学反应速率降低。用冲压发动机模型燃烧室进行了低压燃烧试验,结果显示:进口压力p_in从0.094 MPa变至0.065 MPa,燃烧效率由大变小；压力降低到0.065 MPa时,燃烧室燃烧性能急剧恶化,燃烧极不稳定,随时可能因压力波动或油气参数变化而熄火。无传焰槽时燃烧效率随压力的变化规律与有传焰槽的一致,但燃烧效率相对低一些。

关键词: 冲压喷气发动机;燃烧室;低压