Optimization and integration of image-based schlieren and background-oriented schlieren techniques for two- and three-dimensional analysis of indoor airflows

基于图像的纹影和面向背景的纹影技术的优化和集成，用于室内气流的二维和三维分析

• 批准号: 444059583
• 负责人: Professor Dr.-Ing. Conrad Völker
• 金额: --
• 依托单位: Lehrstuhl Bauphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/444059583?language=en
• 关键词: Optimization; integration; image; based; schlieren

This proposal focuses on the optimization and integration of image-based schlieren and background-oriented schlieren techniques. Both techniques allow the visualization of refractive index gradients caused by density differences in transparent media. These techniques can be implemented for two and three-dimensional evaluation, visualization, and quantification of airflow. In these applications, the difficulty lies in the small density gradients that define the indoor airflow. A schlieren mirror that is unique in its size and quality is used in this project. As the schlieren images captured with the help of the schlieren mirror can only provide a two-dimensional projection of the three-dimensional flow field, the background-oriented schlieren technique is to be used. Preliminary investigations show that its sensitivity is nearly equal to the sensitivity of the schlieren mirror. With the help of two or five cameras that capture the measurement field of the background-oriented schlieren system, the flow can be reconstructed three-dimensionally and evaluated quantitatively.Previous studies indicate that it is not possible to qualitatively or quantitatively compare the spatial and temporal unsteady flows that are recorded by the schlieren mirror and the background-oriented schlieren technique. Therefore, an aim of this project is to merge both optical systems by placing a tomographic background-oriented schlieren system perpendicular to the schlieren mirror. Combining these techniques yields a substantial potential for validating and developing various flow reconstruction methods. By capturing the airflow simultaneously, problems that are associated with the built environment and the indoor air can be comprehensively investigated.

该提案重点关注基于图像的纹影和面向背景的纹影技术的优化和集成。两种技术都可以可视化由透明介质中的密度差异引起的折射率梯度。这些技术可用于气流的二维和三维评估、可视化和量化。在这些应用中，困难在于定义室内气流的小密度梯度。该项目使用了尺寸和质量独特的纹影镜。由于借助纹影镜捕获的纹影图像只能提供三维流场的二维投影，因此需要使用面向背景的纹影技术。初步研究表明，其灵敏度与纹影镜的灵敏度几乎相当。借助两个或五个相机捕获背景导向纹影系统的测量场，可以对流动进行三维重建并定量评估。先前的研究表明，不可能定性或定量比较纹影镜和背景导向纹影技术记录的空间和时间非定常流动。因此，该项目的目标是通过垂直于纹影镜放置面向断层摄影背景的纹影系统来合并两个光学系统。结合这些技术可以产生验证和开发各种流重建方法的巨大潜力。通过同时捕获气流，可以全面调查与建筑环境和室内空气相关的问题。