Collaborative Research: A Micropatterned Wettability Approach for Superior Boiling Heat Transfer Performance

CBET-1235867PI：Daniel Attinger(爱荷华州立大学)和C.Megaridis(UIC)这个跨机构的项目横跨热流体工程、材料科学和优化领域，主要目标是设计、制造和研究被称为超亲水的新型表面。这些微米和纳米结构的表面将超疏水区域(对水具有很强的亲和力)与超疏水区域(对水蒸气具有很强的亲和力)并列在一起。因此，通过以并行和优化的方式控制汽相和液体的传输，它们在池沸腾中表现出优异的性能。这项研究将开发一种新的金属涂层工艺，该工艺可扩展，并适用于工业换热器。主要的科学挑战在于理解、控制和优化超亲表面上的沸腾现象。两亲和超亲表面将首次在技术上相关的金属衬底上制造。这项技术基于可喷绘图案的涂层，这是一个美国领导地位受到海外挑战的工业部门。该研究将为双亲性和超亲性表面沸腾强化奠定理论基础。这项工作具有挑战性，因为沸腾涉及多相和多尺度的传输现象(蒸发始于亚微米厚的薄膜，而分离的气泡是毫米大小)和严重的瞬变过程。为了协助设计和实验，将进行建模工作。对于简单的表面形貌(或疏水和亲水区域的图案)，将开发分析模型来定性地解释池沸腾增强。还将进行计算流体动力学模拟，以帮助理解实验数据，确定沸腾强化的动力学机制，并评估复杂表面形貌的性能。这项工作将以图案设计优化方法为特色，以确定沸腾性能的最佳地形。这种新型超亲表面的性能将通过一系列实验进行评估，包括表面润湿性测量、涂层物理表征、高速可视化以及成核和池沸腾曲线。这项研究涉及各种多学科主题的丰富基础现象，旨在提供一种创新的解决方案，在沸腾配置中以更高的速率传递热量。这项工作的发展将影响热交换器等技术，热交换器广泛用于大多数能源密集型行业，仅在美国每年的总消耗量就超过15万亿Btu。因此，这项研究产生的非增量改进有可能产生巨大的能源节约，进而减少能源浪费和环境污染。两名研究生将在这个项目中接受教育，该团队将接触芝加哥地区未被充分代表的少数民族。

CBET-1235867PIs: Daniel Attinger (Iowa State Univ.) and C. Megaridis (UIC)This cross-institutional project straddles the areas of thermofluid engineering, materials science and optimization, with main goal to design, fabricate and study novel surfaces that are called ?superbiphilic.? These micro- and nanostructured surfaces juxtapose superhydrophobic areas (with strong affinities for water) with superhydrophobic areas (with strong affinities for water vapor). As such, they show superior performance in pool boiling by controlling the transport of the vapor and liquid phases in a parallel and optimal manner. The study will develop a novel coating-on-metal process, which is scalable and relevant to industrial heat exchangers. The main scientific challenge lies in understanding, controlling and optimizing boiling phenomena on the superbiphilic surfaces. For the first time, biphilic and superbiphilic surfaces will be fabricated on technically relevant, metallic substrates. The technology is based on sprayed-on patternable coatings, an industrial sector where US leadership is challenged from overseas. The research will develop a theoretical science base for boiling enhancement on biphilic and superbiphilic surfaces. The work is challenging because boiling involves multiphase and multiscale transport phenomena (evaporation starts in a sub-micrometer thick film, while detaching bubbles are millimeter-sized) and severely transient processes. To assist with the design and experiments, a modeling effort will be carried through. For simple surface topographies (or patterns of hydrophobic and hydrophilic domains), analytical models will be developed to explain the pool boiling enhancement in a qualitative manner. Computational fluid dynamic simulations will also be performed, to help understand the experimental data, identify the dynamic mechanisms responsible for the boiling enhancement, and evaluate the performance of complex surface topographies. The effort will feature a pattern design optimization approach to determine optimum topographies for boiling performance. The performance of the novel superbiphilic surfaces will be evaluated by a series of experiments, including surface wettability measurements, coating physical characterization, high speed visualization, as well as nucleation and pool boiling curves.The research, which involves rich fundamental phenomena in a variety of multidisciplinary topics, intends to deliver an innovative solution to transferring heat at superior rates in boiling configurations. The developments from this work will affect -among other technologies- heat exchangers, which are widely used in most energy-intensive industries, which collectively consume over 15 quadrillion Btu/yr in the US alone. Consequently, the non-incremental improvements resulting from this research have the potential to generate tremendous energy savings, and in turn, reduce energy waste and environmental pollution. Two graduate students will be educated in this program, and the team will reach out to underrepresented minorities in the Chicago area.