Upgrade of a time-resolved particle image velocimetry system

拉瓦尔大学液压机械实验室对产生水力发电的水轮机进行研究。它是加拿大唯一专门从事水轮机研发的独立实验室。它的研究旨在更好地了解水轮机的水动力和结构行为。实验室的合作伙伴是从事水轮机设计的领先公司Andritz Hydro、GE Renewable Energy、Voith Hydro以及水轮机运营商Hydro-Québec和EDF。我们目前的研究项目旨在了解混流式水轮机内流动引起的潜在破坏性涡轮振动的性质。混流式水轮机是加拿大水电站中数量最多的水轮机。该项目将为参与的工业合作伙伴的研发部门提供知识、工具和方法，以优化涡轮机设计或操作，以便在不影响机器寿命的情况下增加灵活性。这将反过来简化可再生能源(风能、太阳能)在电网上的集成。*该项目(以及我们实验室中的许多其他项目)的主要测量系统是时间分辨粒子图像测速系统(TR-PIV)。PIV系统测量流动内部的速度场，以便提供有关流动行为的信息。我们的PIV系统的时间分辨特性意味着它可以高速获取速度场，最高可达每秒725个速度场。通过这种方式，可以分析流动现象的快速变化。例如，我们可以跟踪引起涡轮机振动的大漩涡的时间演变。*本提案的目标是大幅升级我们的TR-PIV系统。这样的系统可以与高速摄像机一起工作。我们的相机性能很好，但它们有两个局限性。首先，它们有相对较小的内存块来存储流动图像。有限的内存大小意味着，对于大多数关键的流动现象，采集时间太短，无法跟踪重要的流动变化。因此，我们将不能完全描述流动现象，也不能完全了解它们在涡轮机结构激振中的作用。其次，将图像从相机传输到计算机需要很长时间，这大大减少了一天内可以执行的测量次数。因此，它降低了其他类型测量的测试台可用性，导致了巨大的能源浪费，因为在图像传输期间，试验台无法停止，并且不必要地增加了设备(试验台、涡轮机模型、传感器)的磨损。**

The Laboratory of Hydraulic Machines of Laval University performs research on hydraulic turbines that produce hydroelectricity. It is the only independent laboratory in Canada specializing in R&D on hydraulic turbines. Its research aims at providing a better understanding of the hydrodynamic and structural behaviour of hydraulic turbines. The Laboratory partners are leading companies involved in hydraulic turbine design, Andritz Hydro, GE Renewable Energy, Voith Hydro, and turbine operators, Hydro-Québec and EDF. Our current research project aims at understanding the nature of potentially damaging turbine vibrations induced by the flow in Francis turbines. Francis turbines are the most numerous turbines in hydro power plants in Canada. The project will provide the R&D departments of the participating industrial partners with knowledge, tools and methodologies to optimize turbine designs or operation in order to increase flexibility without penalizing the machine life. This will in turn ease the integration of renewable energy sources (wind, solar) on the power grid.***The prime measurement system for this project (and many others in our laboratories) is a Time-Resolved Particle Image Velocimetry (TR-PIV) system. A PIV system measures velocity fields inside a flow in order to provide information about the flow behaviour. The time-resolved feature of our PIV system implies that it can acquire velocity fields at high speed, up to 725 velocity fields per second. In this manner, it is possible to analyze fast variations of flow phenomena. For example, we can follow the evolution in time of large vortices that induce turbine vibrations.***The goal of the present proposal is to upgrade substantially our TR-PIV system. Such a system functions with high-speed cameras. Our cameras are highly performant, but they have two limitations. First, they have relatively small memory banks to store the flow images. The limited memory size implies that for a majority of crucial flow phenomena, the acquisition time is too short to track important flow variations. Consequently, we will not be able to fully characterize the flow phenomena and to entirely understand their role in structurally exciting the turbine. Second, the transfer of the images from the cameras to a computer takes a long time, which considerably reduces the number of measurements that can be performed in a day. Consequently, it diminishes the test bench availability for other types of measurements, it leads to an enormous waste of energy since the rig cannot be stopped during image transfers and it increases needlessly the wear of the equipment (rig, turbine model, sensors).**