Photothermal Energy Conversion in Nanofluids

该奖项由2009年美国复苏与再投资法案（公法111-5）资助。热辐射与纳米流体（纳米级胶体悬浮液）的相互作用尚未得到广泛研究。本研究涉及当足够强的热辐射入射到纳米流体时发生的基本热输运现象。具体来说，辐照会引起悬浮纳米颗粒的局部加热，进而引起液体的加热或沸腾。本提案通过一系列的实验和分析来解决相关现象。知识价值。这项研究解决了悬浮纳米粒子选择性吸收热辐射的速率等问题。这项研究的很大一部分是为了确定在加热的纳米颗粒中形成的蒸汽泡与在加热的表面形成的蒸汽泡的形成方式是否相同。因此，可以测定引起沸腾所必需的入射辐射通量。纳米颗粒响应于热辐射而获得的温度，以及在纳米颗粒表面引发沸腾所需的过热水平将被确定。将寻求最佳的纳米流体粒径和颗粒负载分布，以最大限度地提高太阳能吸收，同时最大限度地减少长波发射。更广泛的影响。基于纳米流体的直接吸收式太阳能集热器具有比传统集热器效率更高的应用前景。这可能会导致成本效益和高效的太阳能收集系统。此外，独特的纳米流体可以引发和控制新的化学反应。高中生将参与以太阳能为基础的科学项目。将为本科生开发教学模块。将通过在大众传播媒介上发表意见和社论文章，努力使一般公众参与太阳能的研究和发展，并使其了解情况。

AWARD ABSTRACT0932720PhelanThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The interaction of thermal radiation with nanofluids, which are nanoscale colloidal suspensions, has not been extensively examined. This research deals with fundamental thermal transport phenomena that occur when sufficiently intense thermal radiation is incident upon a nanofluid. Specifically, the irradiation will cause localized heating of the suspended nanoparticles, and, in turn, induce heating or boiling of the liquid. This proposal addresses the relevant phenomena through a series of experiments and analyses. Intellectual Merit. This research addresses questions such as the rate at which suspended nanoparticles selectively absorb thermal irradiation. A large component of the research is aimed at determining whether a vapor bubble nucleates from a heated nanoparticle in the same manner as compared to from a heated surface. Hence, determination of the incident radiative flux necessary to initiate boiling will be achieved. The temperatures obtained by the nanoparticles in response to the thermal irradiation, and the level of superheat required to initiate boiling at the surface of the nanoparticle will be determined. The optimum nanofluid particle size and particle loading distributions to maximize solar absorption while concurrently minimizing long-wavelength emission, will be sought. Broader Impacts. A promising application development of nanofluid-based, direct-absorption solar thermal collectors with efficiencies higher than conventional solar collectors. This may lead to cost effective and efficient solar energy collection systems. Furthermore, the initiation and control of novel chemical reactions may be brought about by irradiating unique nanofluids. High school students will be engaged in solar-energy-based science projects. Teaching modules will be developed for undergraduate students. An effort to involve and inform the general public regarding solar energy research and development will be made through publishing opinion and editorial articles in the popular media.