EAGER: Experimental Investigation of Forced Convection on Hierarchical Micro/Nanoporous Conducting-Lubricating Surfaces

CBET-1449621Kota(新墨西哥州立大学)强制对流换热具有非常广泛的应用基础。它是许多影响我们日常生活的过程和设备所固有的，例如发电、热管理、空间运输、水净化和国防部门的热交换器和散热器。在流体在通道/管道中的强制对流中，由于流动阻力和换热性能与流体流动速度和壁面特性具有相似的依赖关系，前人研究人员发现，任何降低壁面阻力的尝试都不可避免地会导致换热效率降低，而加强换热几乎总是会导致摩擦流动阻力的增加。虽然强化换热是有益的，但墙壁上摩擦的增加需要更多的电力消耗，这是克服它所需的抽水功率。该方案旨在解决这一在过去几十年中备受研究关注的重要而艰巨的问题，即通过采用液体饱和的分层微/纳米孔表面，首次实现了在壁面附近减少流体流动的阻力，但对换热性能的影响可以忽略不计。重点将放在没有相变的液体的强迫对流上。拟议的工作对科学和社会有更广泛的影响，这将通过课程整合和新墨西哥州州立大学本科生和研究生的最新研究/课堂机会来展示。这项活动将直接帮助发展一支多元化的、具有全球竞争力的STEM劳动力队伍，了解并解决国家能源利益的关键问题。为了实现项目的目标和目标，将使用一种新的蚀刻技术在流道内表面制造各种粗糙度的坚固的分级微/纳米孔表面，并将使用精确的重量测量和荧光显微镜技术表征它们的润湿、老化和坚固方面的特征。为了验证这一概念的理论预测，将在微/纳米孔壁表面充满水的微/微通道中对常见冷却剂的强制对流换热性能进行实验研究。记录的压力、温度和流量数据将被后处理，以获得能效指标，该指标将是将相同的泵送功率通过规则/光滑表面的相同尺寸的通道所需的相同泵送功率的增加的努塞尔数。该项目成功完成的结果将为在强迫对流输送中实现显著能效产生新的知识基础，通过提供关于地表亲水性和稳健性、流动稳定性和热输送及其对地表拓扑的依赖的新的基本见解。

CBET-1449621Kota (New Mexico State University)Forced convection heat transfer has a very wide application base. It is inherent to numerous processes and equipment that affect our day-to-day lives such as heat exchangers and heat sinks in power generation, thermal management, space transportation, water purification and defense sectors. In forced convection of liquids in channels/pipes, due to the analogous dependence of flow friction and heat transfer performance on fluid flow velocity and wall/surface characteristics, it was found by prior researchers that any attempt to lower friction at the walls inevitably results in decreased heat transfer rate and efforts to augment heat transfer almost always result in increased frictional flow resistance. While enhanced heat transfer is beneficial, increased friction at the walls demands more electricity consumption in the form of pumping power required to overcome it. This proposal aims to resolve this important and arduous problem that has attracted much research attention in the last few decades i.e., it enables friction reduction near the walls for fluid flow but for the first time, with negligible impact on heat transfer performance by employing liquid-saturated hierarchical micro/nanoporous surfaces. The focus will be on forced convection of liquids without phase change. The proposed work has broader impacts on science and society, which will be demonstrated through curriculum integration and state-of-the-art research/classroom opportunities at the undergraduate and graduate levels at the New Mexico State University. This activity will directly help in developing a diverse, globally competitive STEM workforce that would understand and address critical issues of national interest in energy.For achieving the project goals and objectives, robust hierarchical micro/nanoporous surfaces of various roughness topologies will be fabricated on internal surfaces of flow channels using a novel etching technique, and their wetting, aging, and robustness aspects will be characterized using precise weight measurement and fluorescence microscopy techniques. To verify the theoretical predictions that showed substantial potential of the concept, experimental investigation of forced convective heat transfer performance of common coolants will be carried out in mini/microchannels with water saturating the micro/nanoporous wall surfaces. The recorded data of pressures, temperatures and flow rates will be post-processed to obtain an energy-efficiency metric, which will be the increased Nusselt number for the same pumping power required to pump the same liquid through a same sized channel with regular/smooth surfaces. Outcomes as a result of successful completion of the project will generate new knowledge base for realizing significant energy efficiencies in forced convective transport by providing novel fundamental insights on surface -philicity and robustness, flow stability and thermal transport, and their dependence on surface topology.