基于光学分层层析成像原理的火焰测温法

Flame temperature measurement based on optical sectioning tomography

燃烧火焰温度场的测量无论对研究火焰的结构及生成机理、燃料的混合和燃烧方式,还是对燃烧设备的稳定运行和控制都具有重要的意义。介绍了一种利用高速分层摄像控制系统重建火焰温度场的方法。连续的三维发光体可以看成若干个互相平行的二维发光断层的组合,对发光体某断层进行聚焦摄像,得到的图像是该断层的像和其他断层的离焦像的叠加像。对不同断层分别快速聚焦摄像,得到一组辐射图像,采用图像反演算法,可以重建各断层的原始图像。根据图像灰度和火焰温度之间的关系,可建立火焰的三维温度场。通过蜡烛火焰实验,验证了该方法的可行性。实验结果在一定程度上揭示了火焰内部的辐射分布、温度分布和燃烧结构,反映了火焰的三维燃烧特性。该方法可作为一种新的测量和诊断方法,应用于燃烧火焰三维场参数和其他两相流三维场参数的测量中。

The temperature measurement of combustion flame is very useful in studying flame structure,fuel mixing and combustion,and stable operation and control of combustion equipment.In this paper,the high speed optical sectioning method is introduced to reconstruct the flame temperature field.A 3-D irradiance body can be regarded as a combination of a set of 2-D luminous sections and the corresponding image of the 3-D irradiance body can be regarded as the superposition of the focused and the defocused images.Focusing on each section and taking photos using a single CCD camera,the original luminosity distribution of each section can be retrieved by using the image inversion algorithm.Furthermore,based on the relationship between luminosity and temperature,the temperature distribution of flame can be reconstructed.The candlelight experimental results prove the feasibility of the method and reveal the internal radiation structure of flame.It can be used as a new measurement and diagnostic tool for quantitative characterization of a combustion flame and other two-phase flow parameters field.