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.

目前全世界水利工程面临的主要挑战之一是对现有大坝的检查和修复，这些大坝往往超过了它们的假定寿命。正在建造的新建筑主要是为了开发水电潜力和提供防洪保护。现有的和新的结构都必须考虑到不同的条件，特别是由于气候变化。水工结构需要在水力效率方面进行优化，并提供足够的安全水平--即使在未来可能出现的极端条件下，也要考虑到老化和磨损。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设备开发的，这可能会简化经常发现三维流动过程的实际情况。除了经典的一维/二维测量设备外，光学三维方法也是最近发展起来的，它在流动分析中提供了越来越详细的水平。现代粒子跟踪测速(PTV)方法可以利用一组多台高速摄像机在实验室实验中以高时空分辨率(4D)重建单个水颗粒的运动。除了速度场之外，还可以评估取决于参数的参数，例如3D压力场。在此，提出了一种非侵入式4D PTV系统。新的算法即使在高颗粒密度下也能识别单个颗粒，因此与以前的方法相比，可用的信息可以显著增加。该系统允许以接近全高清分辨率和高达1 kHz的采样率记录粒子场景，用于可变尺寸和高达几个分米的边缘长度的测试体积。由于非侵入式设计，避免了对流场的影响。高性能LED被用作光源。使用荧光示踪剂和相机滤光片可以分离水和空气相，从而可以在适度曝气的流动中使用该系统。提出的4D-PTV系统首次实现了对具有流固耦合作用的大体积水流的时间和空间分辨研究。因此，它可以对获得水利工程领域的知识做出重大贡献，特别是与高度湍流中的能量耗散过程有关的知识。