EAGER: A Novel 3-D Printed PVDF-TrFE Copolymer Wall Shear Stress Measuring Device for Measurement of Wall Shear Stress in Unsteady Flow Applications

EAGER：一种新型 3D 打印 PVDF-TrFE 共聚物壁切应力测量装置，用于测量非定常流应用中的壁切应力

• 批准号: 2219730
• 负责人: Rodward Hewlin
• 金额: $ 21.93万
• 依托单位: University of North Carolina at Charlotte
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2219730&HistoricalAwards=false
• 关键词: EAGER; Novel; Printed; PVDF; TrFE

Wall shear stress measurements and the influence of shear stresses in aerodynamic and physiological flow applications are vital. Although there is widespread literature in aerodynamic and physiological fluid flow research, many of the basic properties of unsteady flows are poorly understood. A major limitation in the experimental validation of various unsteady flow models is insufficient flow measurement instrumentation, specifically a method of direct non-invasive measurement of wall shear stress. The sensitivity and accuracy needed to evaluate the wall shear stresses in complex unsteady flows is not attainable with the existing state-of-the-art measurement technologies. This research effort aims to investigate a multi-layered 3-D printed piezoelectric polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) copolymer sensor as a wall shear stress measuring device candidate. The proposed technology has an advantage in that it contains no moving parts, can potentially perform a direct measurement of wall shear stress, can be mounted directly to the flow surface with no modification, and can be manufactured easily as compared to existing methods. Preliminary results demonstrate that PVDF-TrFE exhibits exceptional sensitivity to deflection with high accuracy and sensitivity.This research effort will focus on implementing this novel sensor technology to perform direct wall shear stress measurements in unsteady flow applications. This research effort will address issues related to sensitivity, installation of the sensor, validation of sensor measurements with particle imaging velocimetry wall shear stress measurements and with exact analytical solutions for Poiseuille, Womersley and Stokes flows, and issues of error introduced by the sensor thickness. If the proposed effort is successful, the proposed methodology will provide ease of fabrication and implementation for a range of sizes of flush mountable sensors that eliminate moving parts increasing robustness, provides a reduction of cost in flow instrumentation tools, and provides a non-intrusive wall shear stress measurement. PVDF-TrFE sensors have never been tested or used for wall shear sensing, thus the electromechanical coupling mechanism that provides shear transduction is not fully understood. This pioneering research effort will determine the fundamental sensing properties of PVDF-TrFE under wall shear, improve sensor fabrication and packaging, and will develop a methodology for high frequency dynamic calibration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

壁剪应力测量以及剪切应力在空气动力学和生理流动应用中的影响至关重要。 尽管在空气动力学和生理流动流研究中有广泛的文献，但对不稳定流的许多基本特性都熟悉。 实验验证各种不稳定流量模型的主要局限性是流量测量仪器不足，特别是一种直接非侵入性测量壁剪应力的方法。 现有的最新测量技术无法实现评估复杂不稳定流中壁剪应力所需的敏感性和准确性。 这项研究工作旨在研究多层的3D打印压电聚乙烯二氟二氟乙烯（PVDF-TRFE）共聚物传感器作为壁剪应力测量器件候选者。所提出的技术具有一个优势，因为它不包含运动部件，可以直接对壁剪应力进行直接测量，可以直接安装在流量表面而无需修改的情况下，并且与现有方法相比，可以轻松制造。初步结果表明，PVDF-TRFE具有高精度和敏感性对挠度表现出异常的敏感性。这项研究工作将着重于实施这种新型的传感器技术，以在不稳定的流动应用中执行直接的壁剪应力测量。这项研究工作将解决与敏感性，传感器安装相关的问题，使用粒子成像的传感器测量结果验证，并通过固定壁剪切应力测量值以及针对Poiseuille，Womersley和Stokes流的精确分析解决方案以及传感器厚度引入的错误问题。 如果提出的努力是成功的，则提出的方法将为一系列可冲洗式固定的传感器提供易于制造和实施，这些传感器消除了增加稳健性的运动部件，从而降低了流量仪器工具的成本，并提供了非侵入性的壁剪应力测量。 PVDF-TRFE传感器从未被测试或用于壁剪切传感，因此尚不完全了解提供剪切转导的机电耦合机制。这项开创性的研究工作将确定PVDF-TRFE在墙壁剪切下的基本感应特性，改善传感器的制造和包装，并将开发一种用于高频动态校准的方法。该奖项反映了NSF的法定任务，并被认为是使用该基金会的知识功能和广泛影响的评估来审查CRETERIA的评估。