CIESC Journal ›› 2016, Vol. 67 ›› Issue (S2): 113-119.DOI: 10.11949/j.issn.0438-1157.20160797

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Photo-thermal properties of MWCNT-H2O nanofluid

QU Jian, TIAN Min, WANG Qian, HAN Xinyue   

  1. School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2016-06-12 Revised:2016-10-31 Online:2016-12-30 Published:2016-12-30
  • Supported by:

    supported by the National Natural Science Foundation of China (51576091) and China Postdoctoral Science Special Foundation (2015T80523).

碳纳米管-水纳米流体的光热转化特性

屈健, 田敏, 王谦, 韩新月   

  1. 江苏大学能源与动力工程学院, 江苏 镇江 212013
  • 通讯作者: 屈健(1980-),男,博士,副教授。
  • 基金资助:

    国家自然科学基金项目(51576091);中国博士后科学基金特别资助项目(2015T80523)。

Abstract:

Stable aqueous suspensions of multi-walled carbon nanotubes (MWCNTs) with mass fractions ranging from 0.0015% to 0.1% were prepared via two-step method.The impacts of mass fraction, setting time, and heating times on the optical absorption property of MWCNT-H2O nanofluid were investigated according to the transmittance measured by UV-VIS-NIR spectrophotometer over the wavelength from 200 to 2000 nm.Furthermore, an insolation experiment was performed to investigate the effects of mass fraction and light irradiation times on the photo-thermal property of MWCNT-H2O nanofluids.Results show that the transmittance of MWCNT-H2O nanofluid was decreased evidently after the addition of MWCNTs in deionized (DI) water, and long setting time leads to smaller transmittance.Heating is beneficial to improve light-absorption property of nanofluids.An optimal mass fraction of 0.01% with respect to the best photo-thermal conversion was found.Compared to DI water, the temperature of MWCNT-H2O nanofluid at the optimal mass fraction was increased by about 15.1℃ (or 22.7%) after a lighting time of 45 min.Additionally, photo-thermal conversion performance is enhanced with increasing the lighting time at a low concentration of nanofluid, while it is just opposite at higher concentrations.The nanoparticle agglomeration may account for the above results.

Key words: nanomaterial, solar energy, photo-thermal property, transmittance, agglomeration

摘要:

通过两步法配制了浓度范围0.0015%~0.1%(质量,下同)的多壁碳纳米管(MWCNT)-水纳米流体,并利用分光光度计对不同浓度、静置时间和加热次数下纳米流体在波长200~2000 nm范围内的透射率进行了测试。同时,还对上述纳米流体开展了闷晒实验,研究了浓度和光照次数对纳米流体光热转换性能的影响。结果表明,水中添加MWCNT后透射率明显下降,纳米流体的透射率随着静置时间的增加而减小,加热有利于提高纳米流体的吸光性能;同时,闷晒实验发现存在利于光热转化的MWCNT-水纳米流体最佳浓度(0.01%),光照45 min后与水相比最佳浓度下的纳米流体温升提高了约15.1℃(或22.7%)。另外,纳米流体浓度较低时其光热转换性能随着光照次数的增加而提高,但浓度较高时则刚好相反,纳米颗粒团聚作用可能是造成上述结果的主要原因。

关键词: 纳米材料, 太阳能, 光热特性, 透射率, 团聚

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