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.

壁面剪切应力测量以及剪切应力在空气动力学和生理学流动应用中的影响至关重要。 虽然在空气动力学和生理学流体流动研究方面有广泛的文献，但对非定常流动的许多基本性质知之甚少。 各种非定常流模型的实验验证中的一个主要限制是流量测量仪器不足，特别是壁面剪切应力的直接非侵入性测量方法。 在复杂的非定常流动中，用现有的最先进的测量技术来评估壁面剪应力所需的灵敏度和准确度是无法达到的。 本研究旨在研究多层3-D打印压电聚偏氟乙烯-三氟乙烯（PVDF-TrFE）共聚物传感器作为壁面剪切应力测量设备的候选者。所提出的技术的优点在于，它不包含移动部件，可以潜在地执行壁剪切应力的直接测量，可以直接安装到流动表面而无需修改，并且与现有方法相比可以容易地制造。初步结果表明，PVDF-TrFE具有出色的灵敏度，偏转与高精度和灵敏度。这项研究工作将集中在实现这种新的传感器技术，在非定常流应用进行直接壁面剪切应力测量。这项研究工作将解决相关的问题的灵敏度，安装的传感器，验证传感器测量与粒子成像测速壁面剪应力测量和精确的分析解决方案Poiquilille，Womersley和斯托克斯流量，和传感器厚度引入的误差问题。 如果所提出的努力是成功的，所提出的方法将提供一系列尺寸的齐平安装的传感器的制造和实施的便利，其消除了增加鲁棒性的移动部件，提供了流量仪表工具的成本的降低，并且提供了非侵入式壁剪切应力测量。PVDF-TrFE传感器从未被测试或用于壁剪切感测，因此提供剪切转换的机电耦合机制尚未完全理解。这项开创性的研究工作将确定PVDF-TrFE在壁面剪切下的基本传感特性，改进传感器的制造和封装，并将开发一种高频动态校准方法。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。