Non-intrusive measurement techniques are required to gain a comprehensive understanding about the processes of soot formation, growth and oxidation. Time-resolved laser-induced incandescence (TiRe-LII), commonly performed 0D or 2D within a flame, has proven to be a very suitable tool for the in situ sizing of soot primary particles. In this work, the technique is expanded to the third dimension by employing volumetric illumination and coupling it with a tomographic approach, which allows to computationally gain 3D information from 2D images taken at various angles. To minimize experimental cost, an approach using nine fiber bundles arranged in a semicircle around the flame and imaging the light onto a single camera is used. The technique is demonstrated on an ethene diffusion flame on a standard burner, providing spatially resolved 3D particle sizes. One focus of this work is to reveal the influence of input parameters such as the local bath gas temperature, which we measured by two-color pyrometry, and local laser fluence, which are both required for an accurate evaluation of the local particle size. It is shown that the assumption of an average temperature may result in a wrong picture even of qualitative soot size evaluation. In the end, a concept is proposed for a simultaneous determination of the 3D distribution of particle sizes through TiRe-LII and the required bath gas temperature via two-color pyrometry using a tomographic approach with only three cameras.

需要非侵入式测量技术来获得对烟灰形成，生长和氧化过程的全面了解。时间分辨的激光诱导的白炽灯（TiRe-LII）通常在火焰中以0D或2D进行，已被证明是原位确定烟尘一次颗粒的非常合适的工具。在这项工作中，该技术通过使用体积照明并将其与层析成像方法相结合而扩展到了三维，从而可以从以不同角度拍摄的2D图像中获得3D信息。为了最大程度地降低实验成本，使用了一种方法，该方法使用围绕火焰围绕半圆排列的九个光纤束，并将光成像到单个摄像机上。该技术在标准燃烧器的乙烯扩散火焰中得到了证明，提供空间解析的3D粒度。这项工作的重点是揭示输入参数的影响，例如我们通过双色高温法测量的局部浴池气体温度和局部激光通量，这两个参数都是准确评估局部粒径所需的。结果表明，即使是定性烟灰尺寸评估，平均温度的假设也可能导致错误的图像。最后，提出了一种概念，该方法通过仅使用三个摄像头的层析成像方法，通过二色高温测定法，通过TiRe-LII同时确定粒径的3D分布和所需的浴液温度。准确评估局部粒度都需要这两个参数。结果表明，即使是定性烟灰尺寸评估，平均温度的假设也可能导致错误的图像。最后，提出了一种概念，该方法通过仅使用三个摄像头的层析成像方法，通过二色高温测定法，通过TiRe-LII同时确定粒径的3D分布和所需的浴液温度。准确评估局部粒度都需要这两个参数。结果表明，即使是定性烟灰尺寸评估，平均温度的假设也可能导致错误的图像。最后，提出了一种概念，该方法通过仅使用三个摄像头的层析成像方法，通过二色高温测定法，通过TiRe-LII同时确定粒径的3D分布和所需的浴液温度。