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采用SST湍流模型对带旋流的三维环形后台阶的流场进行了数值分析,比较了不同孔阶比和来流旋流数对环形后台阶流场的影响.结果表明:在合适的边界条件和计算网格下,SST湍流模型对后台阶流动回流区长度的预测能力最佳;当来流旋流数为1.0时,钝体下游的中心回流区长度可以不受钝体孔阶比的影响,从而保证在多种工况下稳定的火焰;随着来流旋流数的增加,中心回流区长度接近正比例增加,来流预旋改变了钝体下游的流动结构,使轴向速度减小,速度峰值移向燃烧室的外侧壁面.通过对钝体孔阶比和旋流数进行联合优化,可得到合理的中心燃烧位置.
The SST turbulence model was used to analyze the flow field of three-dimensional annular backstep with swirling flow and the influence of different pore-to-pore ratio and the number of incoming swirling flow on the back-flow field was compared.The results show that under the appropriate boundary conditions Under the computational grid, the SST turbulence model has the best predictive ability for the backflow backwash zone length. When the number of incoming swirl flows is 1.0, the length of the central backwash zone downstream of the bluff body can be independent of the aperture ratio of the bluff body. So as to ensure a stable flame under a variety of operating conditions. With the increase of the number of incoming swirls, the length of the central reflux zone increases in a nearly proportional proportion, and the flow pre-swirl changes the flow structure downstream of the bluff body so as to reduce the axial velocity, The peak of velocity moves to the outer wall of the combustion chamber.According to the optimization of the hole-hole ratio and the swirl number of the bluff body, a reasonable central combustion position can be obtained.