4D Particle Tracking Velocimetry system (4D-PTV)

4D 粒子跟踪测速系统 (4D-PTV)

• 批准号: 509934143
• 金额: --
• 依托单位: Fachhochschule Aachen
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2023
• 资助国家: 德国
• 起止时间: 2022-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/509934143?language=en
• 关键词: 4D; Particle; Tracking; Velocimetry; system

One of the major current challenges in hydraulic engineering worldwide is the inspection and rehabilitation of existing dams, which have often exceeded their presumed life time. New structures are being built primarily to develop hydropower potential and to provide flood protection. Varying conditions, particularly due to climate change, must be taken into account for both, existing and new structures. Hydraulic structures need to be optimized in terms of hydraulic efficiency and provide adequate safety level – even under extreme conditions that may arise in future as well as in view of aging and wearing. In this regard, downstream energy dissipation is of particular interest. The majority of existing design approaches were developed in laboratory tests using relatively simple instrumentation, which may simplify reality where often three-dimensional flow processes are found. In addition to classic 1D/2D measuring devices, optical 3D methods have been developed in the recent past, which offer an increasing level of detail in flow analysis. Modern Particle Tracking Velocimetry (PTV) methods allow the reconstruction of individual water particle movement in laboratory experiments with high spatio-temporal resolution (4D) using a set of multiple high-speed cameras. In addition to the velocity fields, depending parameters, e.g. 3D pressure fields, can be evaluated. Herein, a non-intrusive 4D PTV system is proposed. New algorithms enable the identification of individual particles even at high particle densities, so that available information can be significantly increased compared to previous methods. The system allows recording of particle scenes with approximately Full HD resolution and a sampling rate of up to 1 kHz for test volumes of variable dimensions and edge lengths of up to several decimeters. Due to the non-intrusive design, influences on the flow field are avoided. High-performance LEDs are used as a light source. The use of fluorescent tracers and camera filters enables the separation of water and air phases and thus the use of the system in moderately aerated flows. The proposed 4D-PTV system allows for the first time the temporally and spatially resolved investigation of large volumes in water flows with fluid-structure interactions. It can thus make significant contribution to gaining knowledge in the field of hydraulic engineering, in particular in relation to energy dissipation processes in highly turbulent flows.

全球氢化工程的主要挑战之一是对现有大坝的检查和康复，这些坝经常超过其假定的寿命。主要是为了开发水电潜力并提供洪水保护。必须考虑到现有结构和新结构的不同条件，特别是由于气候变化。液压结构需要根据氢化效率进行优化，并提供足够的安全水平 - 即使在将来以及衰老和磨损的极端条件下也可能出现。在这方面，下游能量耗散特别令人感兴趣。现有的大多数设计方法都是在实验室测试中使用相对简单的仪器开发的，这可以简化经常发现三维流动过程的现实。除了经典的1D/2D测量设备外，最近还开发了光学3D方法，该方法在流量分析中提供了越来越多的细节。现代粒子跟踪速度法（PTV）方法允许使用一组多个高速摄像头的高时空分辨率（4D）在实验室实验中重建单个水颗粒运动。除了速度字段之外，取决于参数，例如3D压力场可以评估。在此，提出了一个非侵入性的4D PTV系统。新算法即使在高颗粒密度下也能够鉴定单个颗粒，因此与以前的方法相比，可用信息可以显着增加。该系统允许记录具有大约全高清分辨率的粒子场景，并且采样速率高达1 kHz，以示于可变维度和边缘长度的测试量最多可达多个决定。由于无侵入性的设计，因此避免了对流场的影响。高性能LED用作光源。荧光示踪剂和相机过滤器的使用可以使水和空气相分开，从而在中等充气的流中使用系统。拟议的4D-PTV系统首次允许在水流中暂时，经常解决大量的投资，并通过流体结构相互作用。因此，它可以为在高发光工程领域中获得知识做出重大贡献，特别是与高度湍流中的能量耗散过程有关。