石墨烯量子点GQDs纳米流体导热系数模型

Thermal conductivity model of Graphene Quantum Dots nanofluid

中文关键词: 石墨烯量子点（GQDs）, 纳米流体, 导热系数, 理论模型

英文关键词: graphene quantum dots (GQDs) nanofluids, thermal conductivity model, thermal conductivity

中文摘要:

      本文综合考虑布朗运动、纳米液膜层、粒子簇、微尺寸效应等多种因素的影响，建立了石墨烯量子点（GQDs）强化基液导热系数计算模型，使用Hot Disk热常数分析仪测量去离子水和质量分数分别为0.002%、0.004%、0.006%、0.008%、0.01%的GQDs纳米流体的热导率进行验证，并且用预测模型对更高温度和更高质量分数GQDs纳米流体的导热系数进行了预测。研究表明，模型预测误差不超过2.5%，准确度较高，可以很好地预测不同质量分数GQDs纳米流体在不同温度下的导热系数；GQDs纳米流体由于布朗运动引起的类似对流换热的作用提升了导热系数；而GQDs的添加比例并非越大越好，添加比例过高反而会产生沉降效果，抑制导热系数的提升。

英文摘要:

      In this paper, a comprehensive thermal conductivity prediction model of the Graphene Quantum Dots (GQDs) nanofluids was developed. Four aspects of influencing factors are taken into consideration, including the micro-convection effect caused by Brownian motion, the effect of nano-liquid film layer, ion clusters, and micro-size effect. Hot Disk thermal constant analyzer was used to measure the thermal conductivity of the deionized water with GQDs of different mass fractions(0.002%, 0.004%, 0.006%, 0.008%, 0.01% respectively). The calculation results based on the model showed good accordance with the experiment measurement, with difference in the limit of 2.5%. This demonstrates the validity of the modelin predicting the thermal conductivity of GQDs nanofluids with different mass fractions at different temperatures. GQDs nanoparticles are able to enhance the thermal conductivity, because of thesimilar convective heat transfer caused by Brownian motion. The proportion of GQDs added is not simply the larger the better, a high proportion of input will settle, thus reducing the thermal conductivity.