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: $ 6.41万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760293
• 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.

提出了一项新型的数值和实验研究计划，以研究自由喷气机的混合和湍流特征，以及从实心壁或自由表面偏移的喷气机的混合和湍流特征。这些喷气机发生在许多工程应用中。该研究的主要目的是提供对这些喷气机中湍流混合的科学理解，并创建高质量数据库的存储库，这将使研究社区能够为湍流喷气机开发可靠的预测工具。短期目标将在未来5年内实现，是要了解喷嘴几何形状的变化如何影响自由喷气机的湍流特征，并评估喷气机与刚性壁或自由表面的偏移距离的影响动荡的运输现象。在这个5年的周期中，将训练16个HQP（5博士学位，1个MSC和10 BSC），以执行新颖的实验和数值模拟，从而使他们能够对湍流Jets产生彻底的了解。他们将发展技能，将使他们在学术界或对加拿大具有社会经济重要性的多元化行业做好准备。自由表面。世界一流的时间分析层析成像粒子图像速度计（TROMO-PIV）将用于对三维域（3C-3D）中所有三个速度组件的瞬时和同时测量，以前从未有过的范围在邻近壁或自由表面的湍流喷气机的实验研究中实现。 TROMO-PIV是PIV的最新演变，该技术彻底改变了湍流的实验研究。 3C-3D数据库将用于计算所有平均速度和较高的湍流统计，并执行所提出的湍流喷气机的正交分解。将评估衰减和传播速率，以评估喷嘴几何形状的变化或与边界的偏移距离如何影响湍流喷气机的混合特征。在此提案中鉴定出的喷气机比在湍流建模社区中模拟的规范剪切流更为复杂，并且将代表数值模型的急性测试用例。实验结果还将有助于开发更有效的第二矩封闭，而这些闭合通常没有得到完整的现场测量验证。这些新模型将使工程社区能够减少其对物理模型测试和设计高性能流体系统的依赖。从这项研究中获得的改进理解和新的数值模型将导致创新技术的发展，并在航空航天，HVAC和发电行业的能源效率和环保工程系统的设计。