Abstract: In order to study the flow field characteristics of a new designed low swirl concentric staged combustor, numerical simulation and PIV test were carried out to study different combination scheme of two-stage main and pilot swirlers. The results show that under the low swirl, the airflow half cone angle of the individual pilot swirler is less than 22.3° and the recirculation zone cannot be formed. At the same time, the axial velocity of only pilot airflow has a large velocity attenuation characteristic at the swirlers’ outlet. The formation of the recirculation zone is the result of the interaction between the main and pilot swirlers. The entire flow field is characterized by radial zoning, including the central recirculation zone whose maximum radial dimension is smaller than main swirler outer diameter, and the main airflow is outside the recirculation zone where no recirculation zone is formed. The flow field structure under different swirl number of pilot is basically the same. However, as the pilot swirl number increases, the radial dimension of the central recirculation zone increases.

Key words: Combustor;Swirler;Recirculation zone;Concentric staged;Flow field;Numerical calculation

摘要： 为了研究新设计的一种低旋流中心分级燃烧室流场特性，采用数值模拟和PIV试验结合的方法，针对其头部两级主副模旋流器的不同组合方案开展了研究。研究表明：低旋流下，单独副模旋流器工作时气流半角<22.3°，无法形成回流区，同时，副模气流轴向速度在旋流器出口具有较大的速度衰减特性；回流区的形成是主副模旋流器相互作用的结果，流场呈径向分区特征，中心回流区在内，回流区最大径向尺寸小于主模旋流器外径，主模气流在回流区外，无回流区形成；不同副模旋流数下的流场结构基本一致，随着副模旋流数的增加，中心回流区的径向尺寸增大。

关键词: 燃烧室;旋流器;回流区;中心分级;流场;数值计算