Ridwan Shakerur, Pollack Jordan, McCarthy Matthew
Department of Mechanical Engineering and Mechanics, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States.
Langmuir. 2021 May 25;37(20):6107-6114. doi: 10.1021/acs.langmuir.0c02896. Epub 2021 May 11.
This work characterizes the impact of boiling aqueous nanofluids on engineered surfaces designed for boiling enhancement with pure water. Although micro/nano-engineered surfaces have been shown to enhance boiling, these achievements are typically demonstrated using deionized water or other purified fluids. In parallel, particulate-laden fluids, also known as nanofluids, have been shown to enhance boiling as well. In this study, we investigate a variety of engineered surfaces and the boiling degradation due to the addition of SiO particles at a fixed concentration of 0.2% by volume but varying sizes from 7 nm to 10 μm. Although the addition of SiO particles is shown to moderately improve critical heat flux (CHF) on all the surfaces considered, the heat transfer coefficient (HTC) is seen to deteriorate with the addition of particles of any size. The bare copper surface and a nanostructured surface show particle size-dependent degradation of the HTC due to clogging. Bi-conductive surfaces also show a degradation of the HTC, but it was shown to be independent of the particle size. This work has shown specific and unique degradation mechanisms for each of the surfaces considered including the reduction of nucleation sites and thermal insulation. Additionally, the surfaces tested in this work exhibited a partial-CHF condition occurring with the addition of particles.
这项工作描述了沸腾的纳米流体对为增强纯水沸腾而设计的工程表面的影响。尽管微纳工程表面已被证明能增强沸腾，但这些成果通常是使用去离子水或其他纯净流体来展示的。同时，含颗粒流体，也就是纳米流体，也已被证明能增强沸腾。在本研究中，我们研究了多种工程表面以及在固定体积浓度为0.2%但尺寸从7纳米到10微米变化的情况下，添加SiO颗粒导致的沸腾退化。尽管添加SiO颗粒被证明能适度提高所有所考虑表面的临界热通量（CHF），但传热系数（HTC）却随着任何尺寸颗粒的添加而恶化。裸铜表面和纳米结构表面由于堵塞而显示出与颗粒尺寸相关的HTC退化。双导电表面也显示出HTC的退化，但已证明其与颗粒尺寸无关。这项工作展示了所考虑的每个表面特定且独特的退化机制，包括成核位点的减少和热绝缘。此外，在这项工作中测试的表面在添加颗粒时出现了部分CHF条件。
