Enhanced specific heat capacity of high-temperature molten salt-based nanofluids
Enhanced specific heat capacity of high-temperature molten salt-based nanofluids
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DOI：
10.1016/j.ijheatmasstransfer.2012.10.062
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发表时间：
2013-02-01
影响因子：
5.2
通讯作者：
Shin, Donghyun
中科院分区：
文献类型：
--
作者：
Tiznobaik, Hani;Shin, Donghyun
将四种不同尺寸的二氧化硅纳米颗粒（直径为5、10、30和60 nm）分散在熔融盐低共熔物（碳酸锂和碳酸钾，摩尔比为62：38）中以获得高温工作流体（纳米材料）。采用调制差示扫描量热仪测量熔融盐共晶和纳米材料（熔融盐/纳米颗粒混合物）的比热容。纳米材料的比热容比基础熔盐共晶（基液）的比热容均匀地提高了25%，而与嵌入的纳米颗粒的尺寸无关。实验测量不确定度小于5%。利用电子显微镜进行的材料特性分析表明，在熔盐共晶中加入纳米颗粒会诱导附近的熔盐形成针状结构。这些特殊的结构仅在比热容显著增强的纳米材料中观察到。所观察到的比热容的增强可以通过与嵌入的纳米颗粒的高表面积和由纳米颗粒添加引起的针状结构相关的高比表面能来解释。(C)2012爱思唯尔有限公司保留所有权利。
Four different sized silicon-dioxide nanoparticles (5, 10, 30, and 60 nm in diameter) were dispersed in a molten salt eutectic (lithium carbonate and potassium carbonate, 62:38 by molar ratio) to obtain high temperature operating fluids (nanomaterials). A modulated differential scanning calorimeter was employed to measure the specific heat capacity of the molten salt eutectic and nanomaterials (molten salt/nanoparticle mixture). The specific heat capacity of nanomaterials was enhanced by evenly 25% over that of the base molten salt eutectic (base fluid), regardless of the size of embedded nanoparticles. The measurement uncertainty of experiments was less than 5%. Material characteristic analyses using electron microscopy show that the addition of nanoparticles into the molten salt eutectic induces nearby molten salts to form needle-like structures. These special structures were only observed within the nanomaterials whose specific heat capacity was significantly enhanced. The observed enhancements in specific heat capacity can be explained by the high specific surface energies that are associated with the high surface areas of the embedded nanoparticles and the needle-like structures induced by the nanoparticle addition. (C) 2012 Elsevier Ltd. All rights reserved.