双旋流模型燃烧室高温区演化分析

Evolution Analysis of High Temperature Zones in a Double-Swirled Model Combustor

针对旋流火焰高温区演化问题,使用基于LES-TPDF方法的AECSC两相湍流燃烧程序,模拟径向双旋流模型燃烧室GTMC流场.将温度高于1700K的区域定义为高温区,并将高温区绕中心旋转一圈的时间定义为一个周期,分析在轴向位置Y/D在0~5的范围内燃烧室流场中局部高温区的演化.研究发现流场剪切层附近存在低频率大尺度的旋涡结构(进动涡核PVC),PVC使附近的流体出现进动特征,促进燃烧和放热.在轴向位置Y/D在0~5范围内,筛选出的高温区域在空间上处于同一个大尺度流动结构中,因此在垂直轴向的不同截面上高温区变化频率均在1000~2500Hz,且与进动涡核变化频率近似.综上说明PVC导致燃烧场出现不稳定性,影响高温区形成和演化.

Focusing on the evolution problem of high temperature zones of swirled flame,using Aero Engine Combustor Simulation Code(AECSC),a two-phase turbulent combustion program based on the LES-TPDF method,the flow field of gas turbine model combustor(GTMC),which is a radial double-swirled model combustor,was simulated.When the temperature of the zones is higher than 1700K,they are defined as high tem-perature zones,and the time that high temperature zones rotate around the center once is defined as a period.The evolution of local high temperature zones in the flow field was studied within the range of axial Y/D=0—5.The results show that there exists a low-frequency large-scale vortex structure(precession vortex core(PVC))near the shear layer of the flow field.PVC leads to the precession characteristic of the nearby fluid and promotes combustion and releasing heat.Within the range of Y/D=0—5 in the axial direction,the selected high temperature zones are in the same large-scale flow structure in space.Therefore,the changed frequencies of the high-temperature zones on different sections perpendicular to the axial direction are around 1000—2500Hz,which is similar to the changed frequency of the PVC.To sum up,PVC leads to the instability of combustion field and affects the formation and evolution of high temperature zones.