Fundamental Investigation of Particle-Driven Sweep Convection

CBET-1404017Lage（南卫理公会大学）小规模设备的技术进步受到对更有效的热交换机制的需求的阻碍。本研究的目标是潜在的超高效粒子驱动微对流装置的设计、表征和控制操作，将对电子、航空航天、汽车和能源等多个行业产生强大的经济影响。本项目所探索的构建小通道和小颗粒的最新技术进步，指出了从宏观到微观和纳米尺度应用的潜在可扩展性，使本研究不仅适用于成熟的传热传质设备，也适用于许多新兴行业，如燃料电池、微型发动机、微型化学反应器、生物和空间传感器。分析、数值和实验工作将结合起来，以提供对这种新方法的洞察力和知识，这对于确定其适用于各种应用至关重要。这是一项重要的研究，以获得新的热工效应的基本见解，这是由在对流中使用小颗粒所产生的。该项目还将提高未被充分代表和服务不足的年轻女孩（许多是拉丁裔）对STEM职业的认识。计划开设一门新的微热器件课程，与合作，研究驱动的国际研究项目一起，以及一个新的门户网站，用于传播微热流体学的工作。在对流设备中使用小（微和纳米级）固体颗粒的标准现代方法首先将颗粒与基础流体混合，形成流固（浆）混合物。目前的项目旨在通过研究这些混合物在流动通道与颗粒大小相似的通道中的使用来改变这种标准方法。这种新方法受到肺泡毛细血管中气体转移研究的启发，在肺泡毛细血管中，红细胞颗粒（RBC）流经毛细血管，其流动通道与RBC大小相似。在这种情况下，每个粒子成为混合物的离散组成部分，当它们流过通道时，可能会扫过对流边界层。在平行板和毛细管通道上提出的工作，具有不同尺寸的颗粒（不同的颗粒通道间隙），为开发微设备的基本设计工具提供了一个绘图板，在这些微设备中，必须权衡高传热系数和潜在的压降损失。这种新方法的另一个优点是可以通过简单地改变流过通道的颗粒的数量来控制颗粒的热水力效应，这可以很容易地在飞行中完成。这方面将是具有时变热液压负载的设备的基础，也将在本研究中进行研究。分析、数值和实验工作将结合起来，为这种新方法的对流和流变行为提供见解和知识，这对于确定其适用于各种应用至关重要。这是一项基础研究，对于建立用于验证和优化预测分析模型的实验和数值数据库也是必不可少的。

CBET-1404017Lage (Southern Methodist University)Technological advances in small scale devices are hindered by the need for more efficient heat exchanging mechanisms. The design, characterization and control operation of potentially ultra-efficient, particle-driven micro-convection devices, the objective of this study, will have strong economic impact in several industries, e.g. electronics, aerospace, automotive, and energy. Recent technological advances for building small flow channels and particles, which are explored in this project, points toward the potential scalability of the proposed approach from macro- down to micro- and nano-scale applications, making this study relevant to heat and mass transfer equipment not only in mature but also in many emerging industries, such as fuel-cells, micro-engines, micro-chemical reactors, and bio- and space-sensors. Analytical, numerical and experimental efforts will be combined to provide insight and knowledge of this new approach, critical in determining its suitability for diverse applications. This is an essential study for gaining fundamental insight of new thermo-hydraulic effects resulting from the proposed use of small particles in convection. This project will also boost the awareness of young under-represented and under-served girls, many of Latino origin, about STEM careers. The development of a new Micro-Thermal Devices course with a collaborative, research-driven international study abroad program is planned, as well as a new web portal for disseminating the work on micro-thermo-fluidics.The standard modern approach to using small (micro- and nano-scale) solid particles in convection equipment begins by mixing the particles with a base fluid to form fluid-solid (slurry) mixtures. The present project aims at transforming this standard approach by investigating the use of these mixtures in channels with flow passage similar to the particle size. This new approach has been bio-inspired by the study of gas transfer in alveolar capillaries, where red blood cell particles (RBCs) flow through capillaries having flow passage similar to the RBC size. In this case, each particle becomes a discrete component of the mixture, possibly sweeping the convection boundary layers as they flow through a channel. The proposed work on parallel-plates and capillary channels, with particles of different sizes (different particle-channel gaps), provides a drawing board for developing a fundamental design tool for microdevices, where high heat transfer coefficient must be weighed against potential pressure-drop penalty. Another advantageous effect of the new approach is the possibility of controlling the particle's thermo-hydraulic effects by simply varying the number of particles flowing through the channel, which can be done easily on-the-fly. This aspect, which would be fundamental for devices with time-varying thermo-hydraulic loads, will also be investigated in this study. Analytical, numerical and experimental efforts will be combined to provide insight and knowledge of the convection and rheological behaviors of this new approach, critical in determining its suitability for diverse applications. This is a foundational study, essential also for building experimental and numerical data-banks for validating and optimizing predictive analytical models.