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对中心分级燃烧室冷态流场进行大涡模拟,研究主燃级叶片安装角对流场中大尺度湍流结构运动特性的影响,亚格子尺度湍流及其对大尺度流动结构的影响使用动态Smagorinsky涡黏模型描述。结果显示:流场纵向截面上涡量云图揭示了流场上游出现内外两层涡结构,分别发源于文氏管尾缘和套筒末端,随旋流强度增加,涡层径向尺寸变宽,中心回流区长度缩短。主燃级叶片安装角从20°增加到40°时,流场上游角涡显著减少。下游低压核心与流线束环绕中心重合且偏离轴心,并在流场中下游产生进动涡核。中心轴线上的轴向速度功率谱密度表明,随着叶片安装角增加,涡核进动频率升高。
The large eddy simulation of the cascade flow in the staged combustion chamber was carried out to study the influence of the installation angle of the main combustion stage on the motion characteristics of large scale turbulent structures in the flow field. The effects of subgrid-scale turbulence and its effect on the large-scale flow structure were studied by using dynamic Smagorinsky Eddy viscosity model description. The results show that the vorticity cloud in the vertical section of the flow field reveals the vortex structure inside and outside of the flow field, originating from the venturi trailing edge and the end of the sleeve respectively. As the swirling intensity increases, the radial size of the vortex increases, Center reflow zone length shortened. When the installation angle of the main combustion stage blades is increased from 20 ° to 40 °, the upstream eddy angle in the flow field is significantly reduced. The downstream low pressure core coincides with the streamline around the center and off-axis, and a precessing vortex core is produced in the downstream of the flow field. The axial velocity power spectral density on the central axis shows that as the blade mounting angle increases, the precession frequency of vortex core increases.