Investigation of Asymmetric Free and Confined Three-dimensional Turbulent Jets using Time-Resolved Tomographic Particle Image Velocimetry

使用时间分辨断层粒子图像测速研究不对称自由和受限三维湍流射流

• 批准号: RGPIN-2017-04957
• 负责人: Tachie, Mark
• 金额: $ 3.21万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711313
• 关键词: Investigation; Asymmetric; Free; Confined; Three

A novel numerical and experimental research program is proposed to investigate the mixing and turbulence characteristics of free jets, and jets that are offset from a solid wall or free surface. These jets occur in many engineering applications. The main goal of the research is to provide scientific understanding of turbulence mixing in these jets and create a repository of high-quality databases that will enable the research community to develop reliable predictive tools for turbulent jets. The short-term objectives, which will be achieved over the next 5 years, are to understand how changes in nozzle geometry affects turbulence characteristics of free jets, and to evaluate the effects of offset distance of a jet from a rigid wall or free surface on turbulent transport phenomena. Over this 5-year cycle, 16 HQP (5 PhD, 1 MSc and 10 BSc) will be trained to perform novel experiments and numerical simulations that will enable them to develop a thorough understanding of turbulent jets. They will develop skills that will prepare them for employment in academia or diverse industries of socio-economic importance to Canada. The jets will be produced from nozzles with round, rectangular and elliptical cross sections, and will be offset at different distances from a wall or free surface. A world-class time resolved tomographic particle image velocimetry system (TR-Tomo-PIV) will be used to perform instantaneous and simultaneous measurements of all three velocity components in three-dimensional domain (3C-3D) on a magnitude that has never before been achieved in the experimental study of turbulent jets adjacent to a wall or free surface. The TR-Tomo-PIV is the latest evolution of PIV, a technique that has revolutionized the experimental study of turbulent flows. The 3C-3D databases will be used to calculate all the mean velocities and higher turbulence statistics, and to perform proper orthogonal decomposition of the proposed turbulent jets. The decay and spread rates will be evaluated to assess how changes in nozzle geometry or offset distance from a boundary affect the mixing characteristics of turbulent jets. The jets identified in this proposal are more complex than the canonical shear flows being simulated in the turbulence modelling community, and will represent acute test cases for numerical models. The experimental results will also facilitate the development of more effective second-moment closures, which too often have not been validated against full field measurements. These new models will enable the engineering community to reduce its reliance on physical model testing and design high performance fluid systems. The improved understanding acquired from this research and the new numerical models will lead to the development of innovative technologies and design of energy efficient and environmentally-friendly engineering systems in the aerospace, HVAC and power generation industries.

提出了一种新颖的数值和实验研究计划来研究自由射流以及从固体壁或自由表面偏移的射流的混合和湍流特性。这些射流出现在许多工程应用中。该研究的主要目标是提供对这些射流中湍流混合的科学理解，并创建高质量数据库存储库，使研究界能够开发可靠的湍流射流预测工具。未来五年将实现的短期目标是了解喷嘴几何形状的变化如何影响自由射流的湍流特性，并评估射流与刚性壁或自由表面的偏移距离对流体的影响。湍流传输现象。在这个 5 年周期中，16 名 HQP（5 名博士、1 名硕士和 10 名理学士）将接受培训，进行新颖的实验和数值模拟，使他们能够对湍流射流有全面的了解。他们将培养技能，为他们在学术界或对加拿大具有社会经济重要性的各种行业就业做好准备。 射流将从具有圆形、矩形和椭圆形横截面的喷嘴产生，并且将与墙壁或自由表面以不同的距离偏移。世界一流的时间分辨断层扫描粒子图像测速系统（TR-Tomo-PIV）将用于对三维域（3C-3D）中的所有三个速度分量进行瞬时和同时测量，其幅度是前所未有的。这是在靠近墙壁或自由表面的湍流射流的实验研究中实现的。 TR-Tomo-PIV 是 PIV 的最新发展，这项技术彻底改变了湍流实验研究。 3C-3D 数据库将用于计算所有平均速度和更高的湍流统计数据，并对所提出的湍流射流进行适当的正交分解。将评估衰减和扩散率，以评估喷嘴几何形状的变化或距边界的偏移距离如何影响湍流射流的混合特性。 该提案中确定的射流比湍流建模社区中模拟的规范剪切流更复杂，并且将代表数值模型的急性测试用例。实验结果还将促进更有效的二阶矩闭合的开发，而二阶矩闭合通常尚未针对全场测量进行验证。这些新模型将使工程界减少对物理模型测试的依赖并设计高性能流体系统。从这项研究中获得的更好的理解和新的数值模型将促进航空航天、暖通空调和发电行业创新技术的开发和节能环保工程系统的设计。