双级轴向旋流非预混燃烧和流动特性分析

本文对双级轴向旋流非预混燃烧器进行了研究,应用CFD数值模拟,探索一级旋流器叶片安装角度和文氏管扩张角的角度变化对燃烧特性和温度场以及流动场的影响规律。研究结果表明：文氏管扩张角依次增大过程中,燃烧室内中心回流区中心前移,旋转射流径向扩张角增大；CH4的浓度沿径向分布更加均匀,降低了燃烧室内最高温度。此外在五种不同文氏管角度和一级旋流器叶片安装角度的结构条件下燃烧室中外回流区域温度均低于内回流区域温度。在一级旋流器叶片安装角为55°、二级旋流器叶片安装角为35°时,燃烧器出现回火现象。

Two-stage swirl non-premixed combustion and flowcharacteristics analysis

The fluent numerical simulation software is applied to simulate the two-stage axial swirl non-premixed burner in this paper.During the research process, the blade installation angle of the first-stage swirler and venturi expansion angle is changed, and the influence of the angle change on the flow field and combustion characteristics in the combustion chamber is obtained. The results show thatthe center of the recirculation zone in the combustion chamber advances, and the radial expansion angle of the rotating jet increases with the increase of the expansion angle. The concentration of methane is more evenly distributed along the radial direction which reduces the maximum temperature in the combustion chamber.In addition, it is also found that the temperature in the inner and outer recirculation zones of the combustion chamber is lower than that of the inner recirculation zone under the five different structural conditions .When the one-stage swirl outlet angle reached 55° and the two-stage swirl outlet angle was 35°,the burner has a flashback phenomenon.