多级旋流空气雾化喷嘴高空气动雾化场的数值研究

为有效拓宽采用预膜式空气雾化喷嘴的多旋流分级燃烧室的稳定工作边界，在模型燃烧室上开展了高原及高空工况下气动雾化场的数值研究，采用经过实验验证的数值模拟方法获取了多旋流分级燃烧室的高空气动场和雾化场，分析了低温、低压进口条件对燃烧室流场结构和雾化质量的影响。结果表明:低温及低压进口工况对中心回流区的结构及尺度、速度分布影响较小，但低温会削弱旋流器出口湍动能强度，低压会显著降低旋流空气切向剪切力。相同旋流器压降下，低温、低压条件会造成气液比和韦伯数的降低，导致雾化粒径增大，液滴群轴向穿透深度增加。相关研究结论能够解释该类燃烧室高空点火困难的影响机制。 

Numerical investigation of high altitude aerodynamic and spray fields for multi-swirl airblast atomizer

In order to effectively widen the stable operating limits of multi-swirl staged combustor with prefilming airblast atomizer，the aerodynamic and spray fields of a model combustor under plateau and high-altitude conditions were studied numerically.A numerical method verified by experiments was used to acquire the high-altitude aerodynamic and spray fields of a multi-swirl staged combustor.The influences of low temperature and sub-atmospheric pressure conditions on the flow field structure and atomization quality were analyzed.The results showed that the low temperature and sub-atmospheric pressure conditions had little influence on the flow structure，scale and velocity distributions of central recirculation zone.However，the low temperature weakened the turbulent intensity in swirler outlet，and the sub-atmospheric pressure significantly reduced the tangential shear force of swirling air.Under the same pressure drop of injector，the low temperature and sub-atmospheric pressure conditions led to the decrease of air-liquid ratio and Weber number，which further led to the increase of droplet size and the axial penetration depth of droplet group.The findings from this investigation can explain the influence mechanism of altitude relight difficulty for this kind of combustor.