点火位置对弯管预混火焰传播特性的影响

Influence of Ignition Positions on the Propagation of Premixed Flame in a Curved Duct

通过自行设计的90°弯曲管道燃烧平台,结合纹影光学系统、高速摄像机和离子探针技术,研究了不同点火位置对丙烷/空气预混火焰在90°弯曲管道内传播特性的影响.实验结果表明,水平点火条件下,火焰阵面在水平管道内经历了球形、半球形、指尖形以及Tulip火焰结构4个阶段,预混火焰也从层流燃烧转变为湍流燃烧;垂直点火条件下,火焰阵面在弯曲管道内沿下壁面拉伸,进入水平管段后形成类似Tulip火焰结构,火焰基本处于层流燃烧状态.

In this study, the influence of ignition positions on the propagation of premixed propane/air flame through a square cross-section duct with a 90° bend was investigated. High video camera, schlieren image technique and ion probes were used to record the development of flame front structure and the characteristics of flow field. The results show that, when ignited in the horizontal section, four stages of flame structure, i. e. spherical, hemispherical, finger and tulip- structure, are formed, and the transition to turbulent flame occurs in the horizontal section. When ignited in the vertical section, the keen-edged flame tip moves quickly along the lower wall of the bend, and the flame basically remains laminar.