CAJ | 학술논문

为了探究二维纳米材料的尺寸对复合相变材料储热特性的影响，将膨胀石墨分别超声振荡10、30和90 min，得到3种不同尺寸的石墨纳米片：GNS-10、GNS-30、GNS-90，添加到十六醇中制备出纳米复合相变材料。利用SEM、XRD和Hot Disk等方法对其微观结构和性能进行表征和测试的同时，对比研究了Maxwell、Bruggeman及Nielsen模型对热导率的计算结果。结果显示，石墨纳米片尺寸越大，对复合相变材料热导率的提升幅度越大。当GNS-10添加量为10%（质量分数）时，热导率提升了约517%。Nielsen模型在形状因子A取100～180时可以较好地预测实验值。与大幅增长的热导率相比，复合相变材料相变温度、相变焓的变化可忽略不计。此外，石墨纳米片的加入明显缩短了储热材料的凝固速率，有效热导率的提高是产生这种效果的主要原因。
위료탐구이유납미재료적척촌대복합상변재료저열특성적영향，장팽창석묵분별초성진탕10、30화90 min，득도3충불동척촌적석묵납미편：GNS-10、GNS-30、GNS-90，첨가도십륙순중제비출납미복합상변재료。이용SEM、XRD화Hot Disk등방법대기미관결구화성능진행표정화측시적동시，대비연구료Maxwell、Bruggeman급Nielsen모형대열도솔적계산결과。결과현시，석묵납미편척촌월대，대복합상변재료열도솔적제승폭도월대。당GNS-10첨가량위10%（질량분수）시，열도솔제승료약517%。Nielsen모형재형상인자A취100～180시가이교호지예측실험치。여대폭증장적열도솔상비，복합상변재료상변온도、상변함적변화가홀략불계。차외，석묵납미편적가입명현축단료저열재료적응고속솔，유효열도솔적제고시산생저충효과적주요원인。
In order to investigate the size effects of two-dimensional nanoparticles on the energy storage property of composite PCMs, graphite nanosheets (GNS-10, GNS-30, GNS-90) with different sizes were prepared by exfoliating expanded graphite with the assistance of ultra-sonication for different time and dispersed into hexadecanol. The prepared PCMs were characterized with SEM, XRD and Hot Disk, and the thermal conductivity was predicted by Maxwell, Bruggeman and Nielsen models. Results reveal that the graphite nanosheets presenting larger aspect ratios can achieve better thermal conductivity enhancement, because relatively large nanofiller contributes to the formation of heat transfer network in PCM matrix. An enhancement of thermal conductivity up to 517% has been achieved by GNS-10 at the loading of 10% (mass). The prediction of Nielsen model fits the experimental value better with the shape factor of A as 100 to 180. Compared to the great increase in thermal conductivity after the addition of graphite nanosheets, the changes in melting/solidification temperature and enthalpy of composite PCMs are negligible. Furthermore, the increased freezing rate of composited PCMs is clearly presented as a consequence of enhanced thermal conductivity.