Shear Stress Measurement in Liquid Environments Using MEMS Sensor Arrays

使用 MEMS 传感器阵列测量液体环境中的剪切应力

• 批准号: 0428889
• 负责人: Beth Pruitt
• 金额: --
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-10-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0428889&HistoricalAwards=false
• 关键词: Shear; Stress; Measurement; Liquid; Environments

Proposal Number: 0428889Principal Investigator: Beth PruittAffiliation: Stanford UniversitySensors: Shear Stress Measurement in Liquid Environments using MEMS SensorMicroelectromechanical systems (MEMS) shear stress sensors offer the potential to make measurements in fluids with unprecedented sensitivity, spatial and temporal resolution. The sensor arrays to be developed under this grant will facilitate hydrodynamic measurements which simply cannot be made now, e.g. in ocean reef environments, cardiovascular mockups, turbomachinery components, and flowing cell cultures. MEMS processes offer tight tolerances, reduction in size and power requirements, and parallel fabrication of several designs of floating element direct shear stress sensors in one iteration. These sensor arrays provide an exciting platform to explore factors affecting wall shear stress, such as roughness, floating element and gap size, as well as spatial variation along and across a flow. Additionally, indirect thermal hot wire sensors will be fabricated near and on several of the direct floating element sensors to explore and compare the limits in dynamic response and resolution in varied flow conditions for each sensor type. While most MEMS sensing devices have been developed for measurements in air and utilize unreliable indirect methods, the proposed research addresses the characterization and implementation of direct sensing elements in harsh liquid environments. The goals of this project include: (1) Fabrication of calibrated shear flow sensing arrays suitable for operation in harsh liquid environments, e.g. an ocean surf-zone at depths of 10 to 30 meters. The smallest sensor size to be evaluated is 50 micronmeters, less than the diameter of a human hair; (2) Measurements using the sensors in steady and unsteady flows of saline solutions, and characterization of flows with and without the sensor; and (3) Simulation and analysis of the flow-structure interactions of the sensing elements under varied flows. Optimization of geometry for sensitivity and to minimize flow perturbations. The intellectual merit of this work lies in the development of new shear stress measurement tools, calibration methodology, and accompanying models. Longer term applications of the arrays will enable improved model validation and predictive tools for turbulent flows, fragile coastal ecosystems, and algorithms for control in complex flows. This work will support innovative, interdisciplinary research and development of miniature floating element sensors, designed and calibrated for hydrodynamic measurements to provide useful, real-time shear stress measurements with high resolution and dynamic response. The program integrates theoretical and experimental approaches in a balanced manner. The methodology and equipment developed under the program will lead to new and enhanced educational demonstrations, e.g. utilizing this benchtop system for unsteady flow analysis and measurements in portable channels or in field environments (e.g. oceans, rivers). The intersection of disciplines is wide open for new researchers with no predisposition to background or connections; this program provides particularly important opportunities for underrepresented groups in engineering.

Proposal Number: 0428889Principal Investigator: Beth PruittAffiliation: Stanford UniversitySensors: Shear Stress Measurement in Liquid Environments using MEMS SensorMicroelectromechanical systems (MEMS) shear stress sensors offer the potential to make measurements in fluids with unprecedented sensitivity, spatial and temporal resolution.该赠款中要开发的传感器阵列将有助于现在无法进行的流体动力测量，例如在海洋礁环境中，心血管模型，涡轮机械组件和流动的细胞培养物。 MEMS流程提供紧密的公差，尺寸和功率要求的减小以及在一次迭代中直接剪切应力传感器的几种设计设计。 这些传感器阵列提供了一个令人兴奋的平台，以探索影响墙壁剪切应力的因素，例如粗糙度，浮动元素和间隙尺寸，以及沿着流动的空间变化。 此外，将在几个直接浮动元件传感器附近和几个直接浮动元件传感器上制造间接热线传感器，以探索和比较每种传感器类型的各种流动条件下动态响应和分辨率的限制。 虽然大多数MEMS传感设备都是用于用于测量空气并使用不可靠方法的大多数传感设备，但拟议的研究旨在解决刺激性液体环境中直接传感元素的表征和实施。 该项目的目标包括：（1）制造适用于在刺激性液体环境中操作的校准剪切流动感应阵列，例如海洋冲浪区，深度为10到30米。要评估的最小传感器尺寸是50微米，小于人头发的直径。 （2）使用盐水溶液稳定且不稳定的流动中的传感器进行测量，以及带有和没有传感器的流量的表征； （3）模拟和分析各种流动下的传感元素的流程结构相互作用。优化几何形状，以敏感并最大程度地减少流动扰动。 这项工作的智力优点在于开发新的剪切应力测量工具，校准方法和随附的模型。 阵列的长期应用将实现改进的模型验证和湍流，脆弱的沿海生态系统和算法的预测工具，以控制复杂的流量。这项工作将支持微型浮动元素传感器的创新，跨学科的研究和开发，该传感器设计和校准用于流体动力测量，以提供有用的实时剪切应力测量，并具有高分辨率和动态响应。 该计划以平衡的方式整合了理论和实验方法。该计划下开发的方法和设备将导致新的和增强的教育示范，例如利用此台式系统在便携式通道或现场环境（例如海洋，河流）中进行不稳定的流量分析和测量。对于没有对背景或联系倾向的新研究人员来说，学科的交汇处是开放的。该计划为工程中代表性不足的群体提供了特别重要的机会。