Optimizing Heat Transfer with Nanotechnology

随着人们在克服可再生能源的不稳定性和减少废热/余热(提高换热和储存效率，最终维持发电和用户之间的平衡)方面做出了重大努力，基于混合纳米工程流体的节能热力系统应运而生。目前的研究方案侧重于通过对纳米流体和混合流体在多孔微通道中的强迫对流进行实验、数值和分子动力学研究，来详细、全面地了解流体的动态热行为。这些进展将使以下过程模型得以开发：a)在多孔介质中使用纳米流体和混合纳米流体进行热强化的实验测量：在此背景下，我们将研究不同的多孔介质配置，如在多孔材料块和多孔微通道(最多四个微通道)中的流动。强迫对流实验将使用实验室中制备的纳米流体，如氧化铝/水混合物。还将研究由水中的Al_2O_3和铜组成的混合纳米流体。将对这两种流体的性能进行比较，并确定最佳热流密度和流量的最佳浓度。B)确定纳米流体、混合纳米流体物理性质的分子动力学技术：了解纳米颗粒在基础液体或固体中的相互作用非常重要，以便合理控制系统的分散状态(纳米颗粒散射)、稳定性水平，并通过保持所需的宏观特性和功能最终提高其热性能。分子动力学(MD)模拟将使我们能够克服目前在预测分散在基础流体/固体中的各种纳米材料的热输运性质方面存在的缺陷。C)实验的数值模拟：采用有限元方法，并与实验数据进行比较。这种三维数值模拟的主要挑战之一是如何处理多孔材料和腔壁之间的界面。因此，将通过进行不同的一套实验来克服。D)相变储能材料：在这项研究中，传递到纳米流体和混合流体的热量将被传递到具有相变材料(PCM)的系统中。相变材料可以是块状或微胶囊形式。然而，由于相变材料的导热系数低，将努力采用新的增强方法。拟议的研究计划将使用各种前沿实验和数值技术，以获得对纳米技术传热学的基本了解。这将导致先进的热技术和增强的可持续能源替代品的产生。

With significant efforts being made to overcome the instability of renewable energy sources and reduce waste/excess heat (improving heat transfer and storage efficiency and ultimately maintaining the balance between energy generation and user) energy-efficient thermal systems based on hybrid nano-engineered fluids, are proposed. The current research proposal focuses on a detailed comprehensive understanding of the dynamic thermal behavior by conducting experimental, numerical and molecular dynamic study of forced convection nanofluid and hybrid fluid in a porous micro-channels. These advances will allow process models to be developed for the following; a) Experimental measurement of heat enhancement using nanofluid and hybrid nanofluid in porous media: In this context we will investigate different porous medium configurations such as a flow in a porous material block and in porous microchannels (up to four microchannels). The forced convection experiment will use nanofluid prepared in the laboratory such a Al2O3/water mixture. Hybrid nanofluid consisting of Al2O3 and copper in water will be investigated as well. The performance of these two fluids will be compared and optimum concentration for an optimum heat flux and flow rate will be determined. b) Molecular dynamic technique to determine the physical properties of nanofluid, hybrid nanofluid: Understanding the role of nanoparticles interactions in base liquids or solids is salient in order to have a rational control over the system dispersive regime (nanoparticles scattering), stability level and ultimately promote its thermal performance through maintaining desirable macroscopic properties and functionality. Molecular Dynamics (MD) simulations will allow us to overcome the shortcomings present in predicting the thermal transport properties of various nanomaterials dispersed in base fluids/solids. c) Numerical modelling of the experiment: The finite element method will be used and a comparison with experimental data will be conducted. One of the main challenges in this three-dimensional numerical modelling is how to handle the interface between the porous material and the cavity wall. Thus, will be overcome by conducting different set of experiment. d) Phase change material for energy storage: In this research, heat transferred to the nanofluid and hybrid fluid will be delivered to a system with phase change material (PCM). The phase change material could be in a bulk form or in a micro-encapsulated form. However, because the heat conductivity of PCM is low, effort will be made to incorporate novel methods of enhancing. The proposed research program will use a variety of cutting edge experimental and numerical techniques to gain a fundamental understanding of nanotechnology heat transfer. This will lead to the generation of advanced thermal technologies and enhanced sustainable energy alternatives.