水在不同管径超疏水性微管内的流动特性_姜桂林

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1、山东科学第28卷第1期2015年2月出版SHANDONGSCIENCEVol．28No．1Feb．2015DOI:10．3976/j．issn．1002－4026．2015．01．004【能源与动力】水在不同管径超疏水性微管内的流动特性1111*2姜桂林，张承武，管宁，刘志刚，邱德来(1．山东省科学院能源研究所，山东济南250014;2．南京师范大学能源与机械工程学院，江苏南京210042)摘要:在改性有机硅稀溶液中加入2%全氟辛基氟硅烷以及添加剂配制成超疏水液，采用滴定法在内径分别为0．447、0．728和0．873mm的3种微铜管内壁实现微米级超

2、疏水性涂层涂覆，其水滴表观接触角超过150°。建立微管内流动特性实验系统对超疏水性处理的减阻规律进行了实验研究，分别测量了雷诺数为100～3000时去离子水流过处理前后微铜管时的内部摩擦阻力系数f。研究发现，内壁面的超疏水性处理显著降低了微管内的流动阻力，且该影响随微管内径的增加而增大，实验范围内流动阻力系数最大降幅达29．08%。超疏水涂层使得微管内的流动转捩现象出现滞后，且转捩Ｒe随微管管径增加而略有增大。关键词:超疏水紫铜微管;接触角;摩擦阻力系数;雷诺数;流动转捩中图分类号:O357．1文献标识码:A文章编号:1002-4026(2015)0

3、1-0020-08Flowcharacteristicsofwaterinsuper-hydrophobicmicro-tubeswithdifferentdiameters1111*2JIANGGui-lin，ZHANGCheng-wu，GUANNing，LIUZhi-gang，QIUDe-lai(1．EnergyＲesearchInstitute，ShandongAcademyofSciences，Jinan250014，China;2．SchoolofEnergyandMechanicalEngineering，NanjingNormalvni

4、versity，Nanjing210042，China)Abstract∶Wepreparedsuper-hydrophobicsolutionbyadding2%perfluorinatedoctyltriethoxysilaneandadditivetomodified-organosiliconedilutesolution．Weimplementedmicronordersuper-hydrophobiccoatingoninner-wallsofthreemicro-tubeswithdiametersof0．447mm，0．728mman

5、d0．873mmtoformsuper-hydrophobicmicro-tubes．Thecontactanglesofwaterontheirinnersurfacesarealllargerthan150°．Wefurtherconstructedaninnermicro-tubefluidcharacteristicexperimentalsystemandexploredsuper-hydrophobicresistancereductionlaw．Wemeasuredfrictionalresistancecoefficientsfofd

6、e-ionizedwaterflowingmicro-tubeswithsuper-hydrophobiclayerandwithoutsuper-hydrophobiclayerforＲechangingfrom100～3000．Experimentalresultsshowflowingresistanceinamicro-tubeissignificantlyreducedthroughsuper-hydrophobicprocessing．Moreover，suchresistancegraduallyreduceswiththeincrea

7、seoftheinnerdiameterofamicro-tube．Themaximumdecreasingamplitudecanreach29．08%．Super-hydrophobiccoatingcanmakethetransitionofflowfromlaminartoturbulenceinobviouslydelayedandthetransitionalＲeinmicro-tubesincreaseswiththeincreaseofthediameter．Keywords∶coppermicro-tube;contactangle

8、;fictionalresistancecoefficient;Ｒeynoids;transitionoff