Abstract

Pool boiling can be mentioned as one of the most effective processes of heat transfer regarding the resultant phase change. In this research study, heat transfer in nucleate pool boiling is modeled experimentally with the consideration of surface modification methods utilizing surface photolithography in saturated water at atmospheric pressure. Further, the effects of etching material, confined etched surface, surface area and wettability comparison which is used in fabrication copper surfaces were examined. The images of scanning electron microscopy as well as atomic force microscopy are utilized for obtaining the phase structure and surface morphology in the prepared samples. The experimental results showed that the heat dissipation increases with higher additional area and active nucleation sites densities. Sample with checkered pattern and width of 60 $\mathrm{\mu }\mathrm{m}$ created by photolithography process exhibited the maximum enhancement among other samples and the highest heat transfer coefficient, up to 178% compared to the plain surface. Different parameters, including the bubble dynamic, slide and scrape of the bubbles, area of the heat transfer as well as the capillary flow can be considered as the reasons for improved heat transfer. In addition, the bubble dynamic and enhancement mechanisms are investigated based on the images.

摘要

池沸腾可以说是最有效的相变传热过程之一。在这项研究中，核池沸腾中的传热通过考虑利用表面光刻法在大气压饱和水中的表面改性方法进行实验建模。此外，还检查了用于制造铜表面的蚀刻材料、受限蚀刻表面、表面积和润湿性比较的影响。扫描电子显微镜和原子力显微镜的图像用于获得制备样品的相结构和表面形态。实验结果表明，散热量随着附加面积和活性成核位点密度的增加而增加。$\mathrm{\mu }\mathrm{米}$由光刻工艺制成的样品在其他样品中表现出最大的增强和最高的传热系数，与平面相比高达 178%。不同的参数，包括气泡动态、气泡的滑动和刮擦、传热面积以及毛细流动可以被认为是改善传热的原因。此外，基于图像研究了气泡动态和增强机制。