Effects of WO3 nanowires and TiO2 nanotubes on boiling heat transfer

• Main Authors: Wen-An Chen, 陳文安
• Other Authors: Chen-Kang Huang
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/e9rsu6

碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 107 === Boiling heat transfer exhibits great ability to transport energy. Researches have shown the surface modifications is able to enhance the boiling heat transfer performance. In this study, a pool boiling apparatus was established. A Plate sample was used and therefore the surface modification can be observed by taking the SEM image, and the wettability can be observed by measuring the contact angle. Copper substrate with copper mesh, WO3 nanowires on copper substrate with copper mesh, Ti foil, Ti foil with sintered Ti, and TiO2 nanotubes on Ti foil with sintered Ti or without sintered Ti coating were the modifications to be investigated. Pool boiling experiments were performed by adjusting the input voltage which were 40, 45, 50, and 55 ACV to the cartridge heaters, the superheat and heat flux of heating surface can be calculated with help from SolidWorks Flow Simulation, then the boiling curves were plotted to analyze the boiling heat transfer performances. The results of boiling curves showed that the application of copper mesh increased the boiling heat transfer coefficient by 43.5%. The application of WO3 nanowires reduced the incipient superheat by 2.8 oC comparing to the copper substrate with copper mesh. Comparing to the Ti foil, the application of sintered Ti coating increased the boiling heat transfer coefficient by 95.5%, the application of TiO2 nanotubes reduced the incipient superheat by 1.8 oC and increased heat transfer coefficient by 125.5%. The combined application of TiO2 nanotubes and sintered Ti coating significantly reduced the incipient superheat by 5.4 oC and increased heat transfer coefficient by 66.2% comparing to the Ti foil. The current nanostructures were not durable enough to have consistent results. The pool boiling apparatus was solid, it provided a platform to discover future surface treatments.