| 摘要: |
| 普通含油纳米制冷剂在沸腾时颗粒容易在富油层中团聚，导致油相迁移率极低，无法保证纳米颗粒随制冷剂-油在制冷系统中稳定循环。表面改性可抑制颗粒团聚，故有望提高油相迁移率。本文采用吸光度法测量了不同改性纳米颗粒在含油制冷剂沸腾时的油相迁移率，并研究改性剂碳链长度、纳米颗粒与改性剂之间的嫁接方式对油相迁移特性的影响。实验所用含油纳米制冷剂为TiO2/R141b/NM56，表面改性剂种类包括C1TMS、C3TMS、C8TMS、C16TMS和CTAB。结果表明：5种改性剂均可提高油相迁移率，C16TMS改性效果最好，其油相迁移率最高增加了131.2%；随着改性剂碳链长度从1增加到16，改性效果增加了5.48%~20.11%；共价键嫁接的方式比通过静电吸引的方式改性效果更好。 |
| 关键词: 制冷剂 纳米颗粒 表面改性 沸腾 迁移 润滑油 |
| DOI： |
| 投稿时间：2017-03-21
|
| 基金项目:国家自然科学基金(No.51376124)资助项目。 |
|
| Effect of Surface Modification on Nanoparticle Mixture-to-oil Migration Properties of Nanorefrigerant-oil Mixture |
| Chang Zheng,Lin Lingnan,Ding Guoliang,Peng Hao |
| (Institute of Refrigeration and Cryogenics Engineering, Shanghai Jiao Tong University;Merchant Marine College, Shanghai Maritime University) |
| Abstract: |
| Nanoparticles are likely to aggregate in the oil-rich layer during the boiling of nanorefrigerant–oil mixtures, leading to a low mixture-to-oil migration ratio and making it difficult for nanoparticles to circulate with working fluid in a refrigeration system. Surface modification is a promising approach to raising the mixture-to-oil migration ratio, as it offers the ability to suppress aggregation. In this study, the mixture-to-oil migration ratio of nanoparticles modified by different alkyl chain lengths and grafting mechanisms was measured based on the absorbance method and the effects of the alkyl chain length of the modifier and the grafting mechanisms on the migration characteristics were examined. TiO2 nanoparticles, R141b refrigerant, and NM56 oil were used to prepare the nanorefrigerant–oil mixture. The surface modifiers included C1TMS, C3TMS, C8TMS, C16TMS, and CTAB. The experimental results show that the mixture-to-oil migration ratio increases after the application of these modifiers. The C16TMS exhibits the best enhancement (increasing the migration ratio by 131.2%). It is also found that the mixture-to-oil migration ratio increases by 5.48%–20.11% as the alkyl chain length increases from 1 to 16. The modified nanoparticles grafted by covalent bonds exhibit better migration performance than those that rely on electronic attraction. |
| Key words: refrigerant nanoparticle surface modification boiling migration lubricating oil |
