高各向异性十六酸/膨胀石墨定形相变储热材料的性能  

Properties of High⁃anisotropy Hexadecanoic Acid/Expanded Graphite Form⁃stable Phase Change Heat Storage Materials

作　　者：吴韶飞 闫霆 蒯子函 潘卫国 WU Shaofei;YAN Ting;KUAI Zihan;PAN Weiguo(College of Energy and Mechanical Engineering,Shanghai University of Electric Power,Shanghai 200090,China;Key Laboratory of Clean Power Generation and Environmental Protection Technology in Mechanical Industry,Shanghai 200090,China)

机构地区：[1]上海电力大学能源与机械工程学院,上海200090 [2]机械工业清洁发电环保技术重点实验室,上海200090

出　　处：《材料导报》2021年第4期4186-4193,共8页Materials Reports

基　　金：国家自然科学基金(21546014);上海市科委科技攻关项目(18DZ1202502)。

摘　　要：以十六酸(Hexadecanoic acid,HA)作为基材,添加硫化膨胀石墨(Expanded graphite,EG)作为高导热支撑材料,采用改进的熔融共混⁃凝固定形法制备了高定形精度的HA/EG复合相变材料(Phase change materials,PCMs)样品。对不同参数的复合定形PCMs的热性能进行了系统的测试,考察了样品的微观结构、官能团分布和结晶相以及不同质量分数的EG和样品密度对定形PCMs热性能的影响规律。结果表明,HA与EG均匀混合,且随着HA质量分数和样品密度的增大,两相结合的饱满度提高;HA与EG之间未发生化学反应,仅通过物理作用将HA吸附至EG的多孔结构;纯HA和EG质量分数为30%的定形PCMs的熔融焓分别为275.35 kJ/kg和193.01 kJ/kg,熔点分别为59.53℃和61.08℃。当EG的质量分数为30%且样品密度为900 kg/m3时,HA/EG定形PCMs的水平热导率高达38.42 W/(m·K),相比于纯HA(0.162 W/(m·K))提高了约236倍;而其垂直热导率仅为2.68 W/(m·K),还不及水平热导率的1/14,表现出较高的各向异性。循环稳定性测试结果表明,EG的质量分数为24%和30%的各样品的泄漏量极小,其泄漏量低于0.85%,均未出现明显的泄漏,表现出良好的储/放热循环稳定性。HA/EG定形PCMs是一种性能优良的潜热储存材料,在太阳能热利用中具有广阔的应用前景。Hexadecanoicacid(HA) was selected as the substrate and expanded graphite(EG) was adopted as the supporting material of high thermal conductivity. High form-stable precision HA/EG composite phase change materials(PCMs) were fabricated by the improved method of melting blend-solidification and form-stability. Thermal properties of form-stable PCMs samples with different parameters were systematically measured. The effects of microstructure, functional group distribution, crystalline phase, mass fraction of EG and sample density on the properties of form-stable PCMs were investigated by various instruments. The results showed that the blend of HA and EG were more uniformly and the combination degrees were enhanced with the increasing mass fraction and density of HA, which was absorbed into the porous structure of EG by physical interaction rather than chemical reaction. The melting enthalpy of pure HA and form-stable PCMs with the EG mass fraction and sample density of 30% and 900 kg/m^(3) were 275.35 kJ/kg and 193.01 kJ/kg, and the melting point of 59.53 ℃ and 61.08 ℃, respectively. The horizontal thermal conductivity of the latter was as high as 38.42 W/(m·K), which was about 236 times higher than that of pure HA(0.162 W/(m·K)). The vertical thermal conductivity of the latter was 2.68 W/(m·K), which was less than one-fourteenth of the horizontal, which showed high anisotropy. The cyclic stability test results of all the samples suggested that the EG mass fraction of 24% and 30% with samples had a slight leakage, which were lower than 0.85% and exhibited the wonderful cycle stability. HA/EG form-stable PCM was a kind of latent heat storage material with excellent performance, which had a broad application prospect in solar thermal utilization.

关 键 词：十六酸 膨胀石墨 定形相变材料 各向异性 储热性能 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TB332[动力工程及工程热物理—热能工程]