甲烷扩散火焰空间拟序结构三维运动研究

A Study of the Three-dimensional Movement of a Coherent Structure in a Methane Diffusion Flame Space

提出了基于高速立体视觉的湍流火焰三维运动特性分析方法,该方法首先利用双视角立体镜,使单个CCD靶面同时获得两个不同角度的火焰图像,通过标定得到摄像机参数,最后基于双目视觉理论的三维重建方法获得火焰内部漩涡结构的三维分布及其扩散速度。通过实验重建了甲烷预混火焰中漩涡结构的三维分布及速度场,计算结果表明,由于燃烧速度的径向分布不均匀以及气流受热的膨胀作用,使得火焰面在靠近边界处向外弯曲。

An analytic method was presented for the three-dimensional movement characteristics of turbulent flames based on a high-speed stereoscopic visualization. The method in question first makes use of a stereoscope with dual viewing angles to enable a single CCD (charge coupled device) target surface acquiring simultaneously two flame images from different angles. Through a calibration,the parameters of a video camera can be obtained. Finally,a three-dimensional distribution of the vortex configuration in the flames and its diffusion speed can be determined by using the three-dimensional rebuilding method based on a two-eye visualization theory. Through experiments,reestablished were the three-dimensional distribution and velocity profile of the vortex configuration in a methane premixed flame. The calculation results show that due to the non-uniformity of the radial distribution of combustion speeds and the expansion action of gas flow when it is heated,the flame surface will be bent outwards near its boundary.