Kruse Corey M, Anderson Troy, Wilson Chris, Zuhlke Craig, Alexander Dennis, Gogos George, Ndao Sidy
Mechanical and Materials Engineering, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
Electrical Engineering, University of Nebraska - Lincoln, Lincoln, NE 68588, USA.
Int J Heat Mass Transf. 2015 Mar;82:109-116. doi: 10.1016/j.ijheatmasstransfer.2014.11.023. Epub 2014 Nov 28.
In this paper, we present an experimental investigation of pool boiling heat transfer on multiscale (micro/nano) functionalized metallic surfaces. Heat transfer enhancement in metallic surfaces is very important for large scale high heat flux applications like in the nuclear power industry. The multiscale structures were fabricated via a femtosecond laser surface process (FLSP) technique, which forms self-organized mound-like microstructures covered by layers of nanoparticles. Using a pool boiling experimental setup with deionized water as the working fluid, both the heat transfer coefficients and critical heat flux were investigated. A polished reference sample was found to have a critical heat flux of 91 W/cm at 40 °C of superheat and a maximum heat transfer coefficient of 23,000 W/m K. The processed samples were found to have a maximum critical heat flux of 142 W/cm at 29 °C and a maximum heat transfer coefficient of 67,400 W/m K. It was found that the enhancement of the critical heat flux was directly related to the wetting and wicking ability of the surface which acts to replenish the evaporating liquid and delay critical heat flux. The heat transfer coefficients were also found to increase when the surface area ratio was increased as well as the microstructure peak-to-valley height. Enhanced nucleate boiling is the main heat transfer mechanism, and is attributed to an increase in surface area and nucleation site density.
在本文中，我们展示了对多尺度（微/纳）功能化金属表面池沸腾传热的实验研究。金属表面的传热强化对于诸如核电行业等大规模高热流应用非常重要。多尺度结构是通过飞秒激光表面处理（FLSP）技术制造的，该技术形成了由纳米颗粒层覆盖的自组织丘状微结构。使用以去离子水作为工作流体的池沸腾实验装置，对传热系数和临界热流进行了研究。发现一个抛光的参考样品在40℃过热度下的临界热流为91W/cm²，最大传热系数为23000W/(m²·K)。发现处理后的样品在29℃时的最大临界热流为142W/cm²，最大传热系数为67400W/(m²·K)。发现临界热流的增强与表面的润湿和毛细作用能力直接相关，这种能力起到补充蒸发液体并延迟临界热流的作用。还发现当表面积比以及微结构的峰谷高度增加时，传热系数也会增加。增强的核态沸腾是主要的传热机制，这归因于表面积和形核位点密度的增加。
