Transition and Turbulent Drag Reducing Properties of Microfibrillated Cellulose and Papermaking Fibre Suspensions in Hagen Poiseuille Flow

哈根泊肃叶流中微纤化纤维素和造纸纤维悬浮液的转变和湍流减阻特性

• 批准号: RGPIN-2014-05544
• 负责人: Martinez, Mark
• 金额: $ 1.82万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567233
• 关键词: Transition; Turbulent; Drag; Reducing; Properties

This work will shed light onto a longstanding problem in fluid mechanics, i.e. the transition to turbulence in pipe flow, through use of a novel visualization technique. Optical coherence tomography (OCT), a rapidly emerging technique, will be used in conjunction with confocal scanning laser microscopy (CLSM) and ultrasound Doppler velocimetry (UDV), to create detailed high-resolution spatial and temporal estimates of the flow field in the boundary layer. By doing so we will be able to estimate turbulence quantities and capture tomographic images of turbulent structures in the boundary layer and address fundamental questions such as (i) the relationship between rheology and apparent wall slip, (ii) the nature of the structure of the turbulent puffs and slugs in the boundary layer and (iii) the mechanism for turbulent drag reduction. Although this work has applications in a number of natural and industrial settings, the study is motivated from a pulp and paper application, namely the flow behavior of microfibrillated cellulose (MFC) and papermaking suspensions. The interest in MFC is dramatically increasing dramatically in both the scientific and commercial domains over the last decade. MFC has unique rheological properties and key to further development is a deeper understanding of the flow properties of this material. A five year project is proposed to be conducted by one PhD and one MASc student in either Chemical of Mechanical Engineering. The work will be primarily experimental, with some aspects of analysis of the OCT images.

这项工作将通过使用一种新颖的可视化技术，揭示流体力学中一个长期存在的问题，即管道流向湍流的转变。光学相干断层扫描 (OCT) 是一种快速新兴的技术，将与共焦扫描激光显微镜 (CLSM) 和超声多普勒测速 (UDV) 结合使用，以创建边界流场的详细高分辨率空间和时间估计层。通过这样做，我们将能够估计湍流量并捕获边界层中湍流结构的断层扫描图像，并解决诸如（i）流变学和表观壁滑移之间的关系，（ii）边界层结构的性质等基本问题。边界层中的湍流喷流和段塞以及 (iii) 湍流减阻机制。尽管这项工作在许多自然和工业环境中都有应用，但该研究的动机是纸浆和造纸应用，即微纤化纤维素 (MFC) 和造纸悬浮液的流动行为。过去十年，科学界和商业领域对 MFC 的兴趣急剧增加。 MFC 具有独特的流变特性，进一步开发的关键是更深入地了解这种材料的流动特性。建议由化学工程或机械工程专业的一名博士生和一名硕士生开展一个为期五年的项目。这项工作主要是实验性的，包括 OCT 图像分析的某些方面。