Ultra high boiling performance on nano/microstructured surfaces through electrodeposition of copper and graphene

CBET 1335927PI：Kandlikar拟议项目通过脉冲电沉积石墨烯/碳纳米管及其铜复合材料的超高池沸腾性能对新型微结构的影响？致力于从根本上了解在首选位置具有纳米涂层的增强型微结构表面的沸腾机理。将利用先进的可视化和测量技术，采用高速成像(高达25,000 fps)和尺寸为5-13微米的微热电偶，开发和验证一个结合了微对流在强化沸腾换热中的作用的新模型。该模型将通过COMSOL多物理®数值模拟和基于单独设计的微结构特征的池沸腾实验进一步验证，纳米涂层覆盖在首选区域。通过局部气泡/液体运动和相关换热获得的基本认识将为强化和模拟池沸腾换热和临界热流密度(CHF)提供新的途径。电化学领域的一些最新进展将被用于开发基于多孔石墨烯的结构，这种结构具有高导电性，可以为传热和CHF增强提供可控的形态特征。池沸腾是一种极其重要的传热模式，应用于许多关键技术，包括发电(基于核能、化石燃料和替代能源)、电子冷却、石油化工和加工工业，以及空调和制冷应用。沸腾过程中传热性能的改进通常旨在：(I)减少壁面过热度，(Ii)提高最大传热率，即临界热流密度。拟议的项目为解决这两个性能改进参数提供了一条新的途径。本项目中提出的新方法和模型将为利用沸腾过程提高设备的能效提供一条新的途径。这对于替代热能的利用尤其重要，因为可用温差通常很低，并且至关重要。

CBET 1335927PI: Kandlikar The proposed project Ultra High Pool Boiling Performance on Novel Microstructures through Pulsed Electrodeposition of Graphene/Carbon Nanotubes and their Copper Composites? strives to gain a fundamental understanding of the boiling mechanism over enhanced microstructured surfaces with nanocoatings at preferred locations. A new model that incorporates the role of microconvection in enhancing the boiling heat transfer will be developed and validated by using advanced visualization and measurement techniques employing high speed imaging (up to 25,000 fps), and microthermocouples of 5 - 13 µm dimensions. The model will be further validated through COMSOL Multiphysics® numerical simulation and pool boiling experiments over individually designed microsctruture features with nanocoatings applied over preferred regions. The fundamental insight gained through the localized bubble/liquid motion and the associated heat transfer will provide new avenues in enhancing and modeling the pool boiling heat transfer and critical heat flux (CHF). Some of the recent advances in the field of electrochemistry will be utilized in developing multi-porous graphene-based structures that are highly conductive and can provide controlled morphological features for heat transfer and CHF enhancement.The pool boiling constitutes an extremely important mode of heat transfer that is applied in a number of critical technologies including power generation (nuclear, fossil fuel, and alternative energy source based), electronics cooling, petrochemical and process industries, and air-conditioning and refrigeration applications. Heat transfer performance improvements in the boiling process are generally aimed at: (i) a reduction in the wall superheat, and (ii) an increase in the maximum heat transfer rate, identified as the critical heat flux. The proposed project provides a new pathway to address both of these performance improvement parameters. The new approach and the modeling proposed in this project will provide a new pathway in improving energy efficiencies of devices utilizing the boiling process. This is in particular of great significance for utilizing alternative thermal energy sources, since the available temperature differences are generally low and are of critical importance.