RII Track-4: Tailored Flow Boiling Mechanisms Using 3D Printed Multifunctional Wick Structures

高效和可持续的发电对美国的能源供应/安全和经济至关重要，并且它由热电系统主导，因为2018年83%的电力来自化石燃料和核能。电力生产的效率由蒸汽发生器的性能来检验，即，流动锅炉，这是由局部过早的水干燥过多的不必要的蒸汽毯。为了应对这一挑战，提出的研究将提出一种多功能芯结构，用于有效的液体-蒸气分离，同时提高当前对传热系数和每给定表面积的最大传热速率的技术限制，而不会产生显著的液压压降。一个关键的成功，提出的研究需要先进的制造方法，提出的多功能芯结构与复杂的几何形状。PI将与内布拉斯加大学林肯分校（UNL）的合作者合作，在纳米工程研究核心设施（NERCF）使用最先进的高分辨率金属3D打印机进行研究。此外，该奖学金将大大加强WSU和UNL之间的合作。所获得的新知识将被应用到教育计划中，为未来的工程人员提供能力。流动沸腾系统对于各种能源和热管理应用至关重要。然而，由于系统要求小型化和高功率能耗，散热水平预计将超过传统流动沸腾系统的最大冷却功率，临界热通量（CHF）。CHF是由流体出口处的过早干涸引起的，导致灾难性的系统烧毁，这是由两相流动不稳定性引起的。尽管有广泛的研究，目前还没有可行的解决方案，以减轻CHF长流道。所提出的研究的目的是使用所开发的机械模型、3D打印的多功能芯的协同组合来理解定制的两相流不稳定性和相变传热机制，即，鲨鱼鳍状微孔结构，以及原位/非原位实验验证。拟议的研究将侧重于三个研究重点：（a）开发机械模型，预测定制CHF和传热系数（HTC）机制，（B）开发具有受控尺寸/几何形状的增材制造，同时与内布拉斯加大学林肯分校的合作者通过使用具有高分辨率的最先进的金属3D打印机进行合作，Lumex Avance-25在纳米工程研究核心设施（NERCF），和（c）原位/异位实验验证增强CHF和HTC。该研究成果使开发高效，可扩展和强大的流动沸腾系统，包括发电厂，电子冷却和航空航天应用该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Efficient and sustainable electrical power generation is critical to the U.S. energy supply/security and economy, and it is dominated by thermo-electric systems as the 83% of the electricity in 2018 has been generated from fossil fuels and nuclear energy. The efficiency of the electrical power production is bottlenecked by the performance of a steam generator, i.e., flow boiler, which is caused by a local premature water dryout from excessive unwanted vapor blankets. To address this challenge, the proposed research will a multifunctional wick structure is proposed for effective liquid-vapor separation, to simultaneously advance current technical limits on heat transfer coefficient and maximum heat transfer rate per given surface area without creating significant hydraulic pressure drop. A key success of the propose research requires advanced manufacturing approach for the proposed multifunctional wick structure with complex geometries. The PI will conduct the research working with a collaborator at University of Nebraska, Lincoln (UNL) using the-state-of-the-art metallic 3D printer with the high resolution at Nano-Engineering Research Core Facility (NERCF). Also, this fellowship will greatly strengthen the collaboration between the WSU and UNL. The obtained new knowledge will be implemented into the education plans, which empower future engineering workforce.A flow boiling system is crucial to various energy and thermal management applications. However, as the system demands miniaturization and high power energy consumption, the level of the heat dissipation is expected to exceed the maximum cooling power of the conventional flow boiling system, Critical Heat Flux (CHF). The CHF is caused by the premature dryout at the flow exit, resulting in catastrophic system burnout, which is caused by two-phase flow instability. Despite of extensive research, currently there is no viable solution to mitigate CHF for long flow channel. The objective of the proposed research is to understand tailored two-phase flow instability and phase-change heat transfer mechanisms using the synergistic combination of the developed mechanistic model, 3D printed multifunctional wicks, i.e., shark-fin-like microporous structures, and in-situ/ex-situ experimental validations. The proposed research will focus on three research thrusts: (a) development of mechanistic models, predicting the tailoring CHF and Heat Transfer Coefficient (HTC) mechanisms, (b) development of the additive manufacturing with the controlled micropore sizes/geometries, while working with collaborator at University of Nebraska, Lincoln by using the-state-of-the-art metallic 3D printer with the high resolution, Lumex Avance-25 at Nano-Engineering Research Core Facility (NERCF), and (c) in-situ/ex-situ experimental validations of enhanced CHF and HTC. The research outcomes enable the developments of efficient, scalable, and robust flow boiling systems including power plant, electronic cooling, and aerospace applicationsThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.