喷射角对超声速燃烧室掺混和燃烧的影响

Influences of Cavity Leading Edge Angle on Mixing and Efficiency

针对壁面喷射方式,分别在冷态喷流和燃烧工况下探讨了喷射角的变化对超声速流场中的燃料掺混效果及燃烧效率的影响。研究表明:采用带角度喷射能明显减弱壁面垂直喷射导致的强激波,减小激波/边界层干扰带来的总压损失,在燃料掺混特性方面,减小喷射角会降低近场穿透距离,减弱近场的掺混效果,而对中场的穿透深度及掺混效果影响不大,但带角度喷射的远场的穿透深度及掺混不如垂直喷射。所以垂直喷射时,虽然更多的燃料和空气发生掺混,燃烧效率要高于带角度喷射的,但会以牺牲很大的总压为代价,所以在工程中建议采用带角度喷射配合其他喷射方式。

Influences of injection angle on mixing between fuel and air, combustion mixing and efficiency in supersonic flow field under the condition with/without reactions were numerically investigated. It is found that reducing injection angle can obviously decrease shock wave by transverse injection and reduce loss by shock wave/turbulence boundary layer interaction. For fuel air mixing characteristic, reducing injection angle will weak down penetration depth, weak mixing in near-field and far-field, but almost have no influence on mixing in middle-field. Transverse injection can enhance mixing between fuel and air and increase combustion efficiency to a certain extent at the cost of much total pressure loss. Therefore, reducing fuel injection angle in other injection concepts should be a practical application.