当量比对带凹腔超声速燃烧室流动及燃烧特性的影响

通过调节燃料氢喷射压力参数从而改变油气当量比,分别在冷态喷流与燃烧情况下计算了当量比对流场波系及燃料与空气的掺混、燃烧特性的影响.研究表明:增大当量比会增大燃烧反压,扩大上游边界层分离区,逐渐将激波串推向燃烧室进口;同时发现燃料与空气的混合性能在近场处受当量比影响较大,随当量比增大混合效果明显增强,而在远场处基本不再受当量比变化的影响;增大当量比一定程度增大射流穿透深度,但并不能明显改善燃料分布区不合理问题,导致燃烧效率随当量比单调下降;流场总压损失及凹腔阻力系数均同当量比成正比例关系,而流场摩擦阻力随当量比单调下降,且燃烧使摩擦阻力更小.

Effect of equivalence ratio on flow and combustion characteristics of super-sonic combustor with cavity

Numerical simulation on effect of equivalence ratio on flow field and combustion characteristics of supersonic combustor with cavity under the condition with/without chemical reactions was conducted by adjusting the fuel injection pressure to reach a certain equivalence ratio value.It is found that increasing equivalence ratio enhances combustion backpressure,expands the upstream boundary layer separation zone,and pushes shock train to the entrance of the combustor gradually.Also,enlarging equivalence ratio increases jet penetration depth gradually.In the field near fuel injector ,mixing performance was obviously enhanced by increasing equivalence ratio,while in the field far away from fuel injector,little effect was induced by equivalence ratio.In the aspects of total pressure loss and cavity drag coefficient,they had proportional relationships with equivalence ratio.