Heat Transfer Characteristics of a Fluid with Nano-Encapsulated Phase Change Materials

CBET-1133353 PI：Yagoobi总是需要在大尺度和小尺度上增强传热。通常通过改进相应的表面来实现增强。近年来，研究人员一直在探索通过例如向工作流体中添加相变材料（PCM）来改善工作流体的特性来增强传热。这个拟议的项目将调查有关的纳米级PCM的发展的基本任务。它还将通过理论、数值和实验研究提供有关纳米级PCM浆料（单组分和多组分）传输特性的深入知识;因此，将了解与PCM浆料流动相关的物理学。该项目将在两个相互关联的方向进行。在第一个项目中，将使用一种方法生产新型PCM纳米颗粒基流体，该方法可保证对其特性的高度控制，即长期稳定性和寿命。在第二个方向，这些新的PCM流体的流体力学和传热增强能力将在现实和实际相关的条件下，在介观和微通道流，和宏观尺度的外壳内的自由对流流动进行评估。 从科学的角度来看，这一建议将提高我们对纳米级PCM悬浮液传热增强的理解。它将推出新型PCM（单组分和多组分），具有更宽的温度效率区间，缩短的响应时间，高热容，改善的稳定性和寿命，以及在高浓度下的充分表征的流变行为。这些新的PCM流体的流体动力学特性和传热能力将阐明使用直接实验中的流动中，微尺度通道和宏观尺度的外壳。相应的流场和温度场沿着与传热系数将测量和预测使用数值模拟占现实的流变行为和粘性耗散。这项研究还将揭示PCM的热膨胀对增强外壳内的自由对流流动中的传热的贡献程度，预计这将是显着的。 这种新型PCM基流体的潜在应用的实例，其中它们可以具有巨大的影响，包括诸如高效太阳能利用、电力电子、空间、HVAC R、制造、运输、建筑以及化学、石油、精炼、塑料和橡胶工业的领域。 该项目将涉及本科生和研究生，包括多样化的学生。这项研究将被纳入一本拟议的教科书，并在两所大学教授的研究生课程。将利用两所大学的现有课程，对芝加哥地区的K12学生进行多元化宣传。

CBET-1133353PI:Yagoobi There is always a need to enhance heat transfer in large and small scales. Enhancements in general are achieved by improving the corresponding surfaces. In recent years, researchers have been exploring the enhancement of heat transfer by improving the characteristics of the working fluids via, for example, adding phase change materials (PCMs) to the working fluid. This proposed project will investigate the fundamental tasks pertinent to the development of nano-scale PCMs. It will also provide in-depth knowledge on the transport characteristics of nano-scale PCM slurries (single and multi components) via theoretical, numerical and experimental studies; thus, the physics associated with PCM slurry flows will be understood. The project will be conducted in two inter-related directions. In the first one, novel PCM nano-particle-based fluids will be produced using a method that guarantees a high degree of control of their characteristics, namely long-term stability and longevity. In the second direction, hydrodynamics and heat transfer enhancement capability of these novel PCM fluids will be evaluated under realistic and practically relevant conditions in meso- and micro-channel flows, and free convection flows within macro-scale enclosures. From a scientific perspective, this proposal will improve our understanding of the nano-scale PCM suspensions for heat transfer enhancement. It will introduce novel PCMs (single- and multi-component) with a wider temperature efficiency interval, a decreased response time, high heat capacity, improved stability, and longevity and fully characterized rheological behavior at high concentrations. The hydrodynamic characteristics and heat transfer capabilities of these novel PCM fluids will be elucidated using direct experiments with flows in meso- and micro-scale channels and macro-scale enclosures. The corresponding flow and temperature fields along with heat transfer coefficients will be measured and predicted using numerical simulations accounting for the realistic rheological behavior and viscous dissipation. This study will also reveal the extent of contribution of thermal expansion of PCMs toward enhancement of heat transfer in free convection flows within enclosures, which is expected to be significant. Examples of potential applications of such novel PCM-based fluids, where they can have enormous impact, include such fields as efficient solar energy utilization, power electronics, space, HVAC&R, manufacturing, transportation, construction as well as chemical, petroleum, refining, plastic, and rubber industry. The project will involve undergraduate and graduate students including students of diversity. The research will be integrated into a proposed textbook, and in a graduate course taught at both universities. Outreach to K12 students of diversity in the Chicago area will be conducted, leveraging existing programs at both universities.