Heat Transfer and Fluid Flow in Micro and Mini Scale Devices

这一建议是关于发展稳健的模型，以预测复杂的内部流动系统的热流体性能特征。在制冷、电子冷却、汽车冷却、太阳能加热和无数其他工艺流程的紧凑型传热装置中，可以找到简单和复杂的流结构。在新型紧凑型能源设备（如燃料电池、微流体“芯片实验室”设备、微系统、MEMS和其他下一代技术）中也发现了复杂的流动。有必要进行理论和实验两方面的基础研究，以便更好地确定性能特征并开发用于专门或通用模拟代码的预测模型。本提案旨在研究目前使用紧凑和微流架构的系统设计者所面临的几个基本问题。为这个奖助金周期选定了几个重点领域。这些包括：用于紧凑型和增强型传热装置的微型和微型通道中的单相和两相流，以及电子封装系统中传热和流体流动的实验和理论建模。这些装置通过两种方式促进传热，即增加传热系数和增加表面积。在紧凑型换热器中加强传热的代价是增加压降或减少固定压降的质量流量。拟开展的研究包括对复杂内部流动的热特性和水动力特性的理论和实验分析，以及优化流动结构的并行开发。当精确的模型可用于预测特定装置几何形状的热-水力性能时，紧凑传热装置的最佳设计是最好的。最后，工程师需要考虑许多参数来优化这些设计，例如尺寸（重量和体积）和成本，以及所需的传热和泵送功率。新设备的设计使用现代方法，如熵生成最小化或结构理论也积极追求。当这些方法应用于有限系统时，允许材料的最佳分布，并使系统在压降、表面积和体积的固定约束下自由变形。提出的研究的应用包括提高能源系统的性能，热回收，以及电子和电子系统的热管理。在上一个周期中，这些领域取得了重大进展，发表了大约40篇档案期刊论文，完成了3篇博士论文和2篇硕士论文。可以预期，这项建议中正在考虑的新问题将同样富有成果

This proposal is concerned with the development of robust models for predicting the thermal-fluid performance characteristics of complex internal flow systems. Simple and complex flow architecture is found in compact heat transfer devices for refrigeration, electronics cooling, automotive cooling, solar heating, and in countless other process flows. Complex flows are also found in new compact energy devices such as fuel cells, micro-fluidic “lab on chip” devices, micro-systems, MEMS, and other next generation technologies. There is a need for fundamental study, both theoretical and experimental, to better ascertain the performance characteristics and to develop predictive models for use in specialized or generic simulation codes. This proposal aims to study several fundamental problems now facing designers of systems utilizing compact and micro-flow architecture. Several focus areas have been chosen for this grant cycle. These include: single and two phase flow in micro- and mini-channels for use in compact and enhanced heat transfer devices and experimental and theoretical modelling of heat transfer and fluid flow in electronics packaging systems. These devices promote heat transfer through two ways, namely, increased heat transfer coefficients and increased surface area. The penalty for enhancing heat transfer in a compact heat exchanger is increased pressure drop or reduced mass flow rate for fixed pressure drop. The proposed research involves theoretical and experimental analysis of the thermal and hydrodynamic characteristics of complex internal flows and parallel development of optimized flow architectures. Optimum design of compact heat transfer devices is best achieved when accurate models are available for predicting the thermal-hydraulic performance of a particular device geometry. Finally, the engineer needs to optimize these designs considering many parameters, such as size (weight and volume) and cost, in addition to the required heat transfer and pumping power. The design of new devices using modern methods such as Entropy Generation Minimization or Constructal Theory is also actively pursued. These methods when applied to finite systems, allow for the optimal distribution of material and give the system freedom to morph under the fixed constraints of pressure drop, surface area, and volume. Applications of the proposed research include improving performance of energy systems, heat recovery, and thermal management of electronics and electronics systems. Significant progress in these areas has been made during the last cycle, leading to approximately 40 archival journal publications and the completion of 3 PhD and 2 Master's theses. It is expected that the new problems being considered in this proposal will be equally fruitful.**