Locally resolved flow diagnostics by means of lightfield measurements

对燃烧过程、等离子体技术和高超音速飞行等高焓流场的理解缺乏对温度和组分的瞬时三维分布的测量。一般来说，非侵入式光学诊断方法是一种通用的分析工具，但可能需要广泛的光学访问，这往往是有限的，在感兴趣的问题。其他的光学诊断达到了高水平的分辨率，但仅限于二维。本项目旨在利用光场分析来表征高焓流。原则上，该技术允许从单次摄影曝光确定空间分布。光场成像最近已经商业化。然而，它还没有被用于分析流场，特别是不热的、化学反应性强的和明亮的流动，例如在高超音速飞行的地面试验设施中。第一步，应发展和实施分析三维标量场所需的算法。然后，该方法进行了验证的光场图像与商业相机系统和适当的幻影的援助。这形成了使用高焓流的光场图像来确定化学反应物质的瞬时空间（3D）分布的基础。这样一个收购是独一无二的，是至关重要的高速反应流的评估。

The understanding of high-enthalpy flowfields such as in combustion processes, plasma technology and hypersonic flight lacks the measurement of the instantaneous, three-dimensional distribution of temperatures and species. In general, non-intrusive optical diagnostic methods are a versatile tool for the analysis, but may require extensive optical access, which is very often limited in the problems of interest. Other optical diagnostics reach a high level of resolution, but are limited to two dimensions.This project aims at using lightfield analysis for the characterisation of high-enthalpy flows. In principle, this technology allows to determine spatial distributions from one single photographic exposure. Lightfield imaging has recently become commercially available. However, it has not yet been used for analysing flowfields, particularly not hot, chemically reactive and brightly luminous flows as for example in ground testing facilities for hypersonic flight.In a first step the algorithms required for the analysis of three-dimensional scalar fields shall be developed and implemented. The methods are then validated with the aid of lightfield images taken with a commercial camera system and appropriate phantoms. This forms the basis for using lightfield images of the high-enthalpy flow to determine the instantaneous, spatial (3D) distribution of the chemically reacting species. Such an acquisition is unique and of crucial importance for the assessment of high speed reacting flows.