SGER: Enhanced Heat Transfer Characteristics of Liquid Suspensions Containing Water-Filled Carbon Nanotubes

奖项编号：0543538题目：SGER：含有水填充碳纳米管的液体悬浮液的增强传热特性名称：康斯坦丁·M·梅加里迪斯研究所：伊利诺伊大学芝加哥分校该项目将研究将密封的高压水作为相变材料(PCM)分散在传热液中，目的是同时增加悬浮母液的有效热容和导热系数。这种增强是通过分散一类新的闭合管状纳米管来实现的，这种封闭管状纳米管由充满水的多壁碳纳米管组成，主要处于液体状态。直径小到几纳米的纳米管将被使用，最终目标是生产一种超级纳米流体，这种流体具有极高的冷却能力，特别适合微电子设备。悬浮液的合成将使用大量不同浓度的充满流体的碳纳米管在几种传统的换热流体中，即水、油和乙二醇中。浸渍的液体将进行粘度测试，量化这种特性如何随着纳米管浓度的变化而变化。悬浮液的有效热容及其与纳米管浓度的关系将通过交流量热法测量。悬浮液的有效导热系数将通过瞬时热线法测量，作为纳米管浓度和包覆水含量的函数。最后，将监测悬浮液的稳定性，以创建可行的PCM流体。初步的理论估算表明，母体(主体)流体热容的相对增强是所含水/主体流体质量比的函数。这些估计表明，只有几个百分点的包裹水质量负载可能会将宿主液体的热容提高高达50%甚至更高。拟议的工作将与阿贡国家实验室合作进行，那里拥有大量纳米流体方面的专业知识。智力优势：这项拟议的工作结合了最近公布的纳米流体(包含固体纳米颗粒)和PCM流体(包含包裹其他流体的微胶囊)的优点，合成了具有优异冷却性能的环境友好型纳米流体。在一个封闭的纳米尺度系统(填充的纳米管)中，流体传输、换热和相变现象是一个非常丰富的问题，并研究了大量的纳米空间如何影响传统换热液体的宏观换热性质。这项拟议的工作可以被视为一种尝试，以创造一种具有热-流体性质的复合流体材料，以适应热传递应用，其中过高的热流密度使传统流体无效。更广泛的影响：如果研究成功，预计将对创造新一代纳米流体产生重大影响，这种流体不仅具有优异的导热性能，而且具有极高的比热，从而具有达到或超过具有超高热流密度的电子微系统的严格要求的冷却能力。为此，这项工作将产生宝贵的科学基础和立即用于工业的知识产权。UIC人员将与ANL研究人员互动，而研究的各个方面将通过现有的NSF支持的网站向本科生和K-12教师开放；PI目前参与了一个有12名本科生的REU-NSF网站，以及有9名K-12教师的RET-NSF计划。将开展这些外联/培训活动，以突出所研究的碳纳米管系统在应对现实生活中的热传递技术挑战方面的相关性。

Award Number: 0543538Title: SGER: Enhanced Heat Transfer Characteristics of Liquid Suspensions Containing Water-Filled Carbon NanotubesName: Constantine M. MegaridisInstitution: University of Illinois at ChicagoABSTRACTThis project will investigate the use of encapsulated high-pressure water dispersed as Phase Change Material (PCM) in a heat transfer liquid with the intent to simultaneously increase the effective heat capacity and thermal conductivity of the suspending parent fluid. This enhancement is pursued by dispersion of a new class of closed tubular nanovessels, which consist of multi-wall carbon nanotubes filled with water, mostly in its liquid state. Nanotubes as small as a few nanometers in diameter will be used with the ultimate goal to produce a super nanofluid, which features extremely high cooling capacity uniquely suited for microelectronic devices. Suspensions will be synthesized using large numbers of fluid-filled carbon nanotubes at variable concentrations in several traditional heat transfer fluids, i.e., water, oils and ethylene glycol. The impregnated liquids will be tested for viscosity, quantifying how this property changes with nanotube concentration. The effective heat capacity of the suspensions and its dependence on nanotube concentration will be measured via AC calorimetry. The effective thermal conductivity of the suspensions will be measured as a function of nanotube concentration and encapsulated water content via the transient hot-wire method. Finally, suspension stability will be monitored to create viable PCM fluids. Preliminary theoretical estimates have been made of the relative enhancement of a parent (bulk) fluid heat capacity as a function of the contained water/bulk fluid mass ratio. These estimates suggest that encapsulated-water mass loadings of only a few percent may enhance the heat capacity of the host liquid by up to 50% or even higher. The proposed work will be conducted in collaboration with Argonne National Laboratory where significant expertise on nanofluids exists. Intellectual merit: The proposed work combines the recently documented advantages of nanofluids (which contain solid nanoparticles) and PCM-fluids (which contain microcapsules encasing other fluids) to synthesize an environmentally friendly nanofluid with superior cooling properties. The problem is rich in terms of fluid transport, heat transfer and phase change phenomena in a closed nanoscale system (filled nanotube) and investigates how a large population of these nanovessels could affect the macroscopic heat transfer properties of conventional heat transfer liquids. The proposed work can be viewed as an attempt to create a composite fluid material with thermal-fluid properties tunable to heat transfer applications where exceedingly high heat fluxes render traditional fluids ineffective. Broader impacts: The research, if successful, is expected to have a significant impact in creating a new generation of nanofluids, which feature not only superior thermal conductivity but also extremely high specific heat, thus featuring cooling capacity meeting or exceeding the severe requirements of electronic microsystems with ultra-high heat fluxes. To this end, the work will generate a valuable science base and intellectual property of immediate use to industry. UIC personnel will interact with ANL researchers, while aspects of the research will be made accessible to undergraduate students and K-12 teachers through existing NSF-supported sites; the PI currently participates in a REU-NSF Site with 12 undergraduate students, as well as in a RET-NSF program with 9 K-12 teachers. These outreach/training activities will be conducted to highlight the relevance of the studied carbon nanotube systems in addressing real-life heat transfer technological challenges.