超燃冲压发动机多凹腔串联燃烧室阻力研究

Analysis of Internal Drag of Scramjet Engine with Multi-cavities in Tandem

在直连式试验台上,采用等截面燃烧室对多个凹腔同侧串联布置的燃烧室的阻力进行了试验研究。分析了凹腔深度分别为10、15和20mm,凹腔长深比分别为5和7的不同凹腔组合、凹腔顺序、凹腔距离和凹腔数目在不同燃料当量比下的燃烧室内阻。研究结果表明,在同一燃料当量比下,燃烧室内串联凹腔数目越多,阻力越大,单个阻力较大的凹腔组合后总阻力较大;燃料喷射方式和当量比对燃烧室阻力变化规律影响较大,在小当量比时氢气燃烧放热将可能增加燃烧室内阻;相同当量比和燃料喷射方式下,氢气比煤油燃烧时阻力大;在合适的当量比和燃料喷射方式下煤油燃烧时组合凹腔可能产生正推力。

The internal drag of cavities in tandem is investigated in a constant area scramjet engine on a direct-connected test stand. Cavities with depths of 10,15 and 20 mm,and length to depth ratios of 5 and 7 are adopted to investigate the effect on its drag of different combinations,sequences,distances and numbers of cavities with different fuel injection schemes and equivalence ratios. Results reveal that,for a known fuel injection scheme the more cavities are installed in tandem,the higher is the internal drag; combination of cavities with higher drags leads to higher total drag; fuel injection scheme and equivalence ratio have great impact on combustor drag; with low equivalence hydrogen combustion will increase the internal drag; the drag of hydrogen combustion is higher than kerosene combustion with equal equivalence ratio. For certain suitable fuel injection schemes,multi-cavities may also produce a positive force.