Heat Transfer and Fluid Flow in Micro and Mini Scale Devices

该建议涉及开发用于预测复杂内部流动系统的热流体性能特性的鲁棒模型。在用于制冷、电子冷却、汽车冷却、太阳能加热以及无数其他工艺流程的紧凑型传热设备中，可以发现简单和复杂的流动结构。复杂流动也存在于新的紧凑型能源设备中，例如燃料电池、微流体“芯片实验室”设备、微系统、MEMS和其他下一代技术。有必要进行理论和实验的基础研究，以更好地确定性能特征，并开发用于专业或通用仿真代码的预测模型。该建议的目的是研究几个基本问题，现在面临的设计师的系统，利用紧凑和微流架构。为这一赠款周期选定了几个重点领域。其中包括：微型和小型通道中的单相和两相流动，用于紧凑和增强的传热装置，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。在紧凑型热交换器中增强传热的代价是增加压降或对于固定压降降低质量流率。拟议的研究涉及复杂的内部流动和优化的流动架构的并行开发的热和流体动力学特性的理论和实验分析。当精确的模型可用于预测特定装置几何形状的热工水力性能时，最佳地实现紧凑型传热装置的优化设计。最后，工程师需要优化这些设计，考虑许多参数，如尺寸（重量和体积）和成本，以及所需的传热和泵送功率。使用现代方法，如熵产生最小化或结构理论的新设备的设计也在积极进行。当应用于有限系统时，这些方法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。拟议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。上一个周期在这些领域取得了重大进展，出版了约40份档案期刊，完成了3篇博士论文和2篇硕士论文。预计本提案所考虑的新问题也将同样富有成果。

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.