Laser Doppler Anemometer (LDA) replacement

激光多普勒风速计 (LDA) 更换

• 批准号: RTI-2023-00076
• 负责人: McKennaNeuman, Cheryl
• 金额: $ 6.31万
• 依托单位: Trent University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 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=765967
• 关键词: Laser; Doppler; Anemometer; LDA; replacement

The boundary-layer environmental wind tunnel at Trent University (TEWT) was designed and constructed for simulating the transport of particulate matter by wind. Nearing three decades in operation, this facility is a well-established international leader in aeolian transport research. It is the only facility of its type in the world that is equipped to run under full climate control with varied air temperature (-10 deg C to 35 deg C) and relative humidity (3% to 85%). It is capable of simulating, for example, wind erosion on a farm in Lethbridge during a drought; particle emissions from tailings ponds and stockpiles in the arctic at subfreezing temperatures; and seasonal variation in airborne microplastics transport surrounding waste management facilities throughout Canada. The barrier that we currently face is that our LDA processor, which has run almost continuously during operation of the wind tunnel over the last 13 years, is malfunctioning and cannot be repaired by the manufacturer. It urgently needs to be replaced so that we can fulfill our immediate obligations to sustain graduate student training; conduct experiments on microplastics transport in the atmosphere as a Project Partner with NERC funded colleagues in the UK; and remain competitive in obtaining contract work with industry and various public agencies to assess emission rates and controls. Since acquiring the LDA through a CFI grant awarded in 2009, we have used this instrument daily to carry out research supported by $740K in NSERC Discovery Grant funding. Particles under investigation in our lab may include either aerosols that travel over long distances (km) while in suspension, or larger particles with sufficient mass to constrain their motion to low ballistic hops (cm), and/or creep over short distances (mm). These may originate from sources that are either mineral, organic or anthropogenic, but all are well known to influence air quality and human health. In our daily operations we require a Laser Doppler Anemometer (LDA) to measure the kinetics of both the turbulent airflow structure, which entrains and propels the particles of interest, as well as the particle cloud. A non-contact 2D LDA offers many advantages over older technologies in that it samples rapidly and accurately without inducing flow perturbation caused by inserting a bluff body instrument directly in the flow, particularly one that can be destroyed by particle impact. Using this instrument, our lab was first to capture direct synchronous measurements showing that airflows saturated with particulate matter have increased turbulence intensity. Our overarching aim in future work is to assess the effects of a changing climate on the kinetics of aeolian transport systems that exist throughout high latitude, cold climate regions characteristic of Canada. Such work will build on the pivotal contributions of the TEWT lab toward fundamental understanding of particle transport in atmospheric boundary-layer flows.

特伦特大学（TEWT）的边界层环境风洞是为了模拟风输送颗粒物而设计和建造的。该设施已运行近三十年，是风沙输送研究领域公认的国际领先者。它是世界上同类设施中唯一能够在不同气温（-10 摄氏度至 35 摄氏度）和相对湿度（3% 至 85%）的全面气候控制下运行的设施。例如，它能够模拟干旱期间莱斯布里奇农场的风蚀情况；北极地区零下温度下尾矿库和库存的颗粒物排放；加拿大各地废物管理设施周围空气中微塑料运输的季节变化。我们目前面临的障碍是，我们的 LDA 处理器在过去 13 年的风洞运行过程中几乎连续运行，但出现了故障，且无法由制造商修复。迫切需要更换它，以便我们能够履行维持研究生培养的直接义务；作为项目合作伙伴，与 NERC 资助的英国同事一起进行大气中微塑料传输的实验；并在与行业和各公共机构获得合同工作以评估排放率和控制方面保持竞争力。自从 2009 年通过 CFI 拨款获得 LDA 以来，我们每天都使用该工具进行研究，并得到 NSERC 发现拨款 74 万美元的资助。 我们实验室研究的颗粒可能包括悬浮时长距离 (km) 传播的气溶胶，或具有足够质量以将其运动限制在低弹道跳跃 (cm) 和/或短距离蠕变 (mm) 的较大颗粒。这些污染物可能来自矿物、有机或人为来源，但众所周知，所有这些都会影响空气质量和人类健康。在我们的日常操作中，我们需要激光多普勒风速计 (LDA) 来测量夹带和推动感兴趣粒子的湍流气流结构以及粒子云的动力学。与旧技术相比，非接触式 2D LDA 具有许多优点，因为它可以快速、准确地采样，不会因直接在流中插入钝体仪器而引起流扰动，特别是可能被颗粒冲击破坏的流扰动。使用该仪器，我们的实验室首次捕获直接同步测量结果，表明充满颗粒物的气流增加了湍流强度。我们未来工作的首要目标是评估气候变化对加拿大高纬度、寒冷气候地区存在的风运输系统动力学的影响。此类工作将建立在 TEWT 实验室对大气边界层流中粒子输运的基本理解的关键贡献的基础上。