纳米TiO_2流体表面改性及对真空闪蒸制冰的影响
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摘要
利用电镜扫描法、紫外分光光度法及烘干称重法对纳米TiO_2流体的分散稳定性进行了综合评价,研究了表面活性剂种类及浓度对其分散稳定性的影响。将纳米TiO_2流体引入真空闪蒸制取冰浆系统,研究了纳米TiO_2浓度、表面活性剂浓度及对吸附作用下纳米TiO_2流体真空闪蒸制冰的影响。结果表明,表面活性剂类型对纳米TiO_2流体分散稳定性的影响很大,复合型的分散稳定性最佳,其次是阴离子型;纳米粒子及表面活性剂可以增强真空下纳米TiO_2流体的成核效果,增大含冰率,降低过冷度;表面活性剂浓度是影响真空闪蒸制冰系统压力及闪蒸率的重要因素,系统压力及闪蒸率均随着表面活性剂浓度的增大而增大;另外,确定了在吸附作用下真空闪蒸制冰系统中使用纳米TiO_2流体的最佳条件。在最佳条件下,含冰率为18.35%,过冷度为0.51℃,热导率为0.920W/(m·K),对比蒸馏水有较大改善。吸附作用下真空闪蒸制冰可行性较高,制取冰浆效果优良。
Electron microscopy, UV spectrophotometry and drying weighing were adopted in the experiment to make a comprehensive assessment of the dispersion stability. The effects of surfactant type surfactant and concentration on the dispersion stability of TiO_2 nanofluids were analyzed. In addition, the TiO_2 nanofluids was used for producing ice slurry in the vacuum flash system. The effects of nano-TiO_2 concentration and surfactant concentration on vacuum flash ice-making of TiO_2 nanofluids under the adsorption condition were analyzed. According to the experimental results, four conclusions were gained.① The type of surfactant has great impact on the dispersion stability of TiO_2 nanofluids. The flash performance of nanofluids with composite surfactant is the best, followed by the anions. ② Both nanoparticles and surfactants can enhance the nucleating effect of TiO_2 nanofluids under vacuum, increase the ice packing factor and reduce the supercooling degree. ③ Surfactant concentration has great effects on system pressure and flash rate in vacuum flash system. With the increase of surfactant concentration, both system pressure and flash rate increase. ④ The best experimental condition of the vacuum flash system by using TiO_2 nanofluids are determined. Under the best condition, the ice packing factor is 18.35%, the supercooling degree is 0.51℃, and the thermal conductivity is 0.920 W/(m ·K). Compared with the parameters of distilled water, it is improved greatly.
Electron microscopy, UV spectrophotometry and drying weighing were adopted in the experiment to make a comprehensive assessment of the dispersion stability. The effects of surfactant type surfactant and concentration on the dispersion stability of TiO_2 nanofluids were analyzed. In addition, the TiO_2 nanofluids was used for producing ice slurry in the vacuum flash system. The effects of nano-TiO_2 concentration and surfactant concentration on vacuum flash ice-making of TiO_2 nanofluids under the adsorption condition were analyzed. According to the experimental results, four conclusions were gained.① The type of surfactant has great impact on the dispersion stability of TiO_2 nanofluids. The flash performance of nanofluids with composite surfactant is the best, followed by the anions. ② Both nanoparticles and surfactants can enhance the nucleating effect of TiO_2 nanofluids under vacuum, increase the ice packing factor and reduce the supercooling degree. ③ Surfactant concentration has great effects on system pressure and flash rate in vacuum flash system. With the increase of surfactant concentration, both system pressure and flash rate increase. ④ The best experimental condition of the vacuum flash system by using TiO_2 nanofluids are determined. Under the best condition, the ice packing factor is 18.35%, the supercooling degree is 0.51℃, and the thermal conductivity is 0.920 W/(m ·K). Compared with the parameters of distilled water, it is improved greatly.
引文
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[21]徐会金,巩亮,黄善波,等.金属泡沫内纳米流体强化传热研究[J].工程热物理学报,2014,35(8):1586-1590.XU H J,GONG L,HUANG S B,et al.Heat transfer enhancement of nanofluid in metal foams[J].Journal of Engineering Thermophysics,2014,35(8):1586-1590.
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[23]赵红霞,孙冰洁,冀翠莲,等.真空闪蒸制取冰浆系统分析[J].化工学报,2013,64(8):2724-2729.ZHAO H X,SUN B J,JI C L,et al.Exergy analysis on ice slurry production system by water spray evaporation in vacuum environment[J].CIESC Journal,2013,64(8):2724-2729.
[24]徐爱祥.新型真空液滴制冰特性研究[D].长沙:中南大学,2010.XU A X.Characteristics on freezing of water droplet due to evaporation[D].Changsha:Central South University,2010.
[25]章学来,李跃,王章飞,等.Cu纳米流体真空闪蒸制冰的实验特性[J].化工学报,2017,68(6):2563-2568.ZHANG X L,LI Y,WANG Z F,et al.Experimental characteristics of ice preparation via Cu-nano fluid’s vacuum flash[J].CIESC Journal,2017,68(6):2563-2568.
[26]KUMANO H,HIRATA T,SHIRAKAWA M,et al.Flow characteristics of ice slurry in narrow tubes[J].International Journal of Refrigeration,2010,33(8):1513-1522.
[27]ASAOKA T,TAJIMA A,KUMANO H.Experimental investigation on inhomogeneity of ice packing factor in ice slurry flow[J].International Journal of Refrigeration,2016,70:33-41.
[2]ZHOU D,ZHAO C Y,TIAN Y.Review on thermal energy storage with phase change materials(PCMs)in building applications[J].Applied Energy,2012,92(4):593-605.
[3]EGOLF P W,KAUFFELD M.From physical properties of ice slurries to industrial ice slurry applications[J].International Journal of Refrigeration,2005,28(1):4-12.
[4]方贵银,邢琳,杨帆.动态冰浆蓄冷空调系统及特性[J].电力需求侧管理,2005,75(6):48-50.FANG G Y,XING L,YANG F.Dynamic ice slurries storage systems and its characteristics[J].Power Demand Side Management,2005,75(6):48-50.
[5]董昕玥.真空制冰矿井降温输冰关键技术的研究[D].武汉:武汉理工大学,2013.DONG X Y.Research on key technologies of transporting ice in vacuum ice for deep mine cooling[D].Wuhan:Wuhan University of Technology,2013.
[6]张皖君,蓝蔚青,肖蕾,等.流化冰在水产品保鲜中的应用研究进展[J].食品与机械,2016(7):214-218.ZHANG W J,LAN W Q,XIAO L,et al.Progress on application research of fresh ice for aquatic products preservation[J].Food&Machinery,2016(7):214-218.
[7]郝玲,刘圣春,杨旭凯.动态冰浆的应用及制取方法的现状及展望[J].制冷与空调,2014,14(11):1-10.HAO L,LIU S C,YANG X K.The present situation and outlook about application fields and generation methods of ice slurry[J].Refrigeration and Air-Conditioning,2014,14(11):1-10.
[8]王倩,孙晓红,蓝蔚青,等.保鲜冰在水产品保藏中的应用研究进展[J].食品与机械,2016(3):226-230.WANG Q,SUN X H,LAN W Q,et al.Progress on application research of fresh ice for aquatic products preservation[J].Food&Machinery,2016(3):226-230.
[9]吴鹏,张学军,邱利民,等.二元冰蓄冷系统中的纳米添加剂成核特性研究[J].浙江大学学报(工学版),2009,43(9):1668-1671.WU P,ZHANG X J,QIU L M,et al.Nucleation characteristics of nano-additives in binary ice thermal storage system[J].Journal of Zhejiang University(Engineering Science),2009,43(9):1668-1671.
[10]MAXWELL J C.A treatise on electricity and magnetism[M].Oxford:Clarendon,1955.
[11]宣益民,李强.纳米流体能量传递理论与应用[M].北京:科学出版社,2010:2-4.XUAN Y M,LI Q.An overview on nanofluids and applications[M].Beijing:Scientia Press,2010:2-4.
[12]李强.纳米流体强化传热机理研究[D].南京:南京理工大学,2004.LI Q.Investigation on enhanced heat transfer of nanofluids[D].Nanjing:Nanjing University of Science and Technology,2004.
[13]HU Z S,DONG J X,CHEN G X.Study on antiwear and reducing friction additive of nanometer ferric oxide[J].Tribology International,1998,31(7):355-360.
[14]吴淑英,朱冬生,杨硕.Al2O3-H2O纳米流体的相变蓄冷实验研究[J].工程热物理学报,2009,30(6):981-983.WU S Y,ZHU D S,YANG S.Experimental study on phase change cool storage of Al2O3-H2O nanofluids[J].Journal of Engineering Thermophysics,2009,30(6):981-983.
[15]CHAKRABORTY S,SARKAR I,BEHERA D K,et al.Experimental investigation on the effect of dispersant addition on thermal and rheological characteristics of TiO2,nanofluid[J].Powder Technology,2016,307(1):10-24.
[16]JIA L,PENG L,CHEN Y,et al.Improving the supercooling degree of titanium dioxide nanofluids with sodium dodecylsulfate[J].Applied Energy,2014,124(7):248-255.
[17]SATO T,KOHNOSU S.Effect of surfactant concentration on the stability of aqueous titanium dioxide suspensions[J].Journal of Colloid&Interface Science,1991,143(2):434-439.
[18]GHADIMI A,METSELAAR I H.The influence of surfactant and ultrasonic processing on improvement of stability,thermal conductivity and viscosity of titania nanofluid[J].Experimental Thermal&Fluid Science,2013,51(11):1-9.
[19]HWANG Y,LEE Jan-Keun,LEE Jong-Ku,et al.Production and dispersion stability of nanoparticles in nanofluids[J].Powder Technology,2008,186(2):145-153.
[20]施赛燕,崔晓钰,周宇,等.石墨烯/去离子水纳米流体振荡热管传热性能[J].化工学报,2016,67(12):4944-4950.SHI S Y,CUI X Y,ZHOU Y,et al.Heat transfer performance of pulsating heat pipe with graphene aqueous nano-fluids[J].CIESCJournal,2016,67(12):4944-4950.
[21]徐会金,巩亮,黄善波,等.金属泡沫内纳米流体强化传热研究[J].工程热物理学报,2014,35(8):1586-1590.XU H J,GONG L,HUANG S B,et al.Heat transfer enhancement of nanofluid in metal foams[J].Journal of Engineering Thermophysics,2014,35(8):1586-1590.
[22]刘玉东,李鑫.纳米流体的低温蓄冷释冷特性及其谷电蓄冷应用研究[J].中国电机工程学报,2015,35(11):2779-2787.LIU Y D,LI X.Cold charge and discharge characteristics of nanofluids and its application to ice storage using valley electricity[J].Proceedings of the CSEE,2015,35(11):2779-2787.
[23]赵红霞,孙冰洁,冀翠莲,等.真空闪蒸制取冰浆系统分析[J].化工学报,2013,64(8):2724-2729.ZHAO H X,SUN B J,JI C L,et al.Exergy analysis on ice slurry production system by water spray evaporation in vacuum environment[J].CIESC Journal,2013,64(8):2724-2729.
[24]徐爱祥.新型真空液滴制冰特性研究[D].长沙:中南大学,2010.XU A X.Characteristics on freezing of water droplet due to evaporation[D].Changsha:Central South University,2010.
[25]章学来,李跃,王章飞,等.Cu纳米流体真空闪蒸制冰的实验特性[J].化工学报,2017,68(6):2563-2568.ZHANG X L,LI Y,WANG Z F,et al.Experimental characteristics of ice preparation via Cu-nano fluid’s vacuum flash[J].CIESC Journal,2017,68(6):2563-2568.
[26]KUMANO H,HIRATA T,SHIRAKAWA M,et al.Flow characteristics of ice slurry in narrow tubes[J].International Journal of Refrigeration,2010,33(8):1513-1522.
[27]ASAOKA T,TAJIMA A,KUMANO H.Experimental investigation on inhomogeneity of ice packing factor in ice slurry flow[J].International Journal of Refrigeration,2016,70:33-41.