Parin Riccardo, Rigon Michele, Bortolin Stefano, Martucci Alessandro, Del Col Davide
Department of Industrial Engineering, University of Padova, Via Venezia 1, 35131 Padova, Italy.
Materials (Basel). 2020 Feb 15;13(4):878. doi: 10.3390/ma13040878.
We developed hybrid organic-inorganic sol-gel silica coatings with good durability in harsh environment (high temperatures, high vapor velocities) and with slightly hydrophobic behavior, sufficient to promote dropwise condensation (DWC) of pure steam. DWC is a very promising mechanism in new trends of thermal management and power generation systems to enhance the heat transfer during condensation as compared to film-wise condensation (FWC). The sol-gel coatings have been prepared from methyl triethoxy silane (MTES) and tetraethyl-orthosilicate (TEOS) and deposited on an aluminum substrate. The coatings were optimized in terms of precursor ratio and annealing temperature highlighting potentials and limits of such mixtures. A comprehensive surface characterization before and after saturated steam condensation tests has been performed and related to the thermal measurements for evaluating the heat transfer augmentation as compared to FWC obtained on untreated aluminum surfaces. The results showed that the developed hybrid organic-inorganic sol-gel silica coatings are promising DWC promoters.
我们开发了一种有机-无机杂化溶胶-凝胶二氧化硅涂层，该涂层在恶劣环境（高温、高蒸汽流速）下具有良好的耐久性，且具有轻微的疏水性能，足以促进纯蒸汽的滴状冷凝（DWC）。与膜状冷凝（FWC）相比，DWC是热管理和发电系统新趋势中一种非常有前景的机制，可增强冷凝过程中的传热。溶胶-凝胶涂层由甲基三乙氧基硅烷（MTES）和正硅酸四乙酯（TEOS）制备而成，并沉积在铝基板上。通过优化前驱体比例和退火温度，突出了此类混合物的潜力和局限性。在饱和蒸汽冷凝试验前后进行了全面的表面表征，并将其与热测量相关联，以评估与未处理铝表面上获得的FWC相比的传热增强情况。结果表明，所开发的有机-无机杂化溶胶-凝胶二氧化硅涂层是很有前景的DWC促进剂。
