Pool boiling heat transfer of FC-72 on pin-fin silicon surfaces with nanoparticle deposition
Pool boiling heat transfer of FC-72 on pin-fin silicon surfaces with nanoparticle deposition
复制标题
DOI：
10.1016/j.ijheatmasstransfer.2018.05.033
复制
发表时间：
2018-11-01
影响因子：
5.2
通讯作者：
Sunden, Bengt
中科院分区：
文献类型：
--
作者：
Cao, Zhen;Liu, Bin;Sunden, Bengt
本研究采用干法刻蚀方法在硅表面制备了两种微针翅结构，即交错针翅(#1)和具有空白区的排列针翅(#2)。然后对微针翅片表面进行进一步的静电处理，分别沉积纳米氧化铁(-35 nm)8h和16h，即#1-8h、#1-16h、#2-8h和#2-16h。以FC-72为工质，在常压下对过冷池沸腾换热进行了实验研究。结果表明，与光滑表面相比，微针翅片表面对池沸腾换热有显著的强化作用，最大过热度显著降低。此外，临界热流密度也有很大提高，如#1的临界热流密度几乎是光滑表面的两倍。一般来说，纳米粒子沉积可以进一步强化池沸腾换热，包括换热系数和临界热流密度(CHF)。采用高速可视化技术对换热性能的机理进行了研究。比较了在低热流密度、中等热流密度和高热流密度下，添加纳米颗粒和不添加纳米颗粒的微针翅表面的气泡行为。测定了FC-72在实验表面的挥发性能，并在此基础上提出了一个修正的CHF模型来预测实验CHF_5。据此，提出了一种可能的心力衰竭增强机制。(C)2018爱思唯尔有限公司。保留所有权利。
In the present study, two types of micro-pin-fin configurations were fabricated on silicon surfaces by a dry etching method, i.e., staggered pin fins (#1) and aligned pin fins with empty areas (#2). The micro pin-fin surfaces were then further modified by depositing FeMn oxide nanoparticles (-35 nm) electrostatically for 8 h and 16 h, respectively, namely #1-8h, #1-16h, #2-8h and #2-16h. Subcooled pool boiling heat transfer was experimentally studied on these surfaces at atmospheric pressure, using FC-72 as the working fluid. The results showed that in comparison to the smooth surface, pool boiling heat transfer was significantly enhanced by the micro-pin-fin surfaces and the maximum superheat was considerably decreased. Additionally, critical heat fluxes were also greatly improved, e.g., the critical heat flux on #1 was almost twice of that on the smooth surface. Generally, the nanoparticle deposition could further enhance pool boiling heat transfer, including the heat transfer coefficient and critical heat flux (CHF). High speed visualizations were taken to explore the mechanisms behind the heat transfer performance. The bubble behavior on the micro-pin-fin surfaces with and without nanoparticles was compared at low, moderate and high heat fluxes, respectively. The wickability of FC-72 on the test surfaces was measured, based on which, a modified CHF model was proposed to predict the experimental CHF5. Accordingly, a possible mechanism of CHF enhancement was described. (C) 2018 Elsevier Ltd. All rights reserved.