SGER: Exploring New Hybrid Polymer-Nanofluids with Enhanced Flow and Heat Transfer Characteristics

北伊利诺伊大学机械工程系M. Kostic提出了一项未经测试的新想法，即将减阻聚合物添加剂与纳米颗粒结合起来，从而开发出新型减阻传热纳米流体，即在普通基础流体中稳定的金属和金属氧化物纳米级颗粒悬浮液。我们的目标是首次生产出混合纳米流体，这种混合纳米流体不仅具有观察到的现有纳米流体的传热增强作用，而且同样重要的是，它提高了悬浮稳定性并减少了流动摩擦。高分子聚合物添加剂带来的流体结构的复杂性，以及与不同基液中纳米颗粒不可预测的相互作用，为定制具有理想和增强特性的新型混合流体带来了许多有待探索的挑战，也可能带来不可预见的机遇。在基础液中使用不同纳米颗粒的初步研究表明，与基础液或相同类型但尺寸较大的颗粒的体积分数相比，不同纳米颗粒的导热性要高得多。此外，使用所谓的一步直接气相沉积方法制备的非常小的金属纳米颗粒比使用两步混合方法制备的较大的金属氧化物纳米颗粒的增幅要高得多。然而，现有的由阿贡国家实验室（ANL）开发的一步法，虽然是一个很好的概念，但有严重的缺点，并且实际上阻碍了进一步的发展，因为迄今为止只生产了非常有限数量的增强纳米流体。第一个目标将是通过将减阻聚合物添加剂与纳米颗粒相结合，开发出减阻传热纳米流体。随后，对这些新型聚合物纳米流体的热力学、宏观流动和传热特性进行了研究。智力优势：该提案的核心是将减阻聚合物与高导热纳米流体相结合的新想法。减少流动摩擦和高导热流体的发展可能会给传热领域带来革命性的变化。这些研究的结果可用于优化流体性质及其在现有关键应用以及新兴和新颖应用中的使用。更广泛的影响：这项探索性研究可能为开发具有聚合物添加剂（包括生物纳米流体）的多种复杂纳米流体开辟道路，被称为poly -纳米流体，具有前所未有的应用潜力。自然界充满了纳米流体，如血液，这是一种复杂的生物纳米流体，不同的纳米颗粒（在分子水平上）完成不同的功能。通过在实验室和自然界中研究（和理解）纳米流体，使用新的和可用的实验技术，并通过开发基于这些流体和相关现象的计算机模型，可以开发出具有增强性能的纳米流体定制设计的新方法和工具。这项探索性研究也将导致未来的项目，在这些项目中，宏观尺度的测量将与纳米尺度的结构和动力学测量相结合，使用激光、小角度x射线和中子散射技术。可能的应用包括在新的和关键的应用中更有效的冷却和加热，环境控制和清洁，生物医学应用以及纳米结构的定向自组装。

SGER: Exploring New Hybrid Polymer-Nanofluids with Enhanced Flow and Heat Transfer Characteristics M. Kostic, Department of Mechanical Engineering, Northern Illinois UniversityAn exploratory work on an untested and novel idea to combine drag-reducing, polymer additives with nanoparticles, and thus develop new-hybrid, drag-reducing heat-transfer nanofluids, namely, stable suspensions of metal and metal-oxide nano-scale particles in common base fluids, is proposed. The goal will be to produce, for the first time, hybrid nanofluids that not only have the observed heat transfer enhancement of existing nanofluids, but equally importantly, have improved suspension stability and reduced flow friction. Complexities in fluid structure introduced by macromolecular polymer additives and unpredicted interactions with nanoparticles in different base fluids, should open up a lot of challenges to be explored and possibly unforeseen opportunities for tailoring new hybrid fluids with desired and enhanced characteristics. Initial studies using different nanoparticles in base fluids have demonstrated much higher thermal conductivity than in the base fluids or with comparable volume fractions of the same type but larger size particles. Furthermore, the increase was much higher with very-small metal nanoparticles using the so called one-step, direct vapor-deposition method, than with larger metal-oxide nanoparticles using the two-step mixing method. However, the existing one-step method developed in Argonne National Laboratory (ANL), although an excellent concept, has critical shortcomings, and is virtually stalling further development since only very limited quantities of enhanced nanofluids have been produced so far. The first objective will be to develop drag-reducing heat-transfer nanofluids by combining drag-reducing, polymer additives with nanoparticles. Subsequently, thermo-mechanical, macroscopic flow and heat transfer properties of these new polymer-nanofluids will be undertaken. Intellectual Merit: The core of this proposal is the novel idea of combining drag-reducing polymers with high thermal conductivity nanofluids. The development of reduced flow friction and high thermal conductivity fluids may revolutionize the field of heat transfer. The results of such studies could be used to optimize fluid properties and their use for existing critical applications as well as emerging and novel applications. Broader Impact: This exploratory research may open the road for development of diverse, complex nanofluids with polymer additives (including biological nanofluids), dubbed POLY-nanofluids, with unprecedented application potential. Nature is full of nanofluids, like blood, a complex biological nanofluid where different nanoparticles (at molecular level) accomplish different functions. By studying (and understanding) nanofluids in the lab and nature, using new and available experimental techniques, and by developing computer based models of these fluids and related phenomena, new methods and tools for custom-design of nanofluids with enhanced properties may be developed. This exploratory research should also lead to future projects where macro-scale measurements will be combined with nano-scale measurements of structure and dynamics using laser light and small angle x-ray and neutron scattering techniques. Possible applications include more efficient cooling and heating in new and critical applications, environmental control and cleanup, bio-medical applications, and directed self-assembly of nanostructures.