基于纳米颗粒小尺度效应的纳米流体有效热导率模型

摘要

通过分析基于纳米颗粒小尺度效应的纳米流体热流传递的机理,建立纳米流体有效热导率的预测模型.将本模型与实验数据及经典模型对比,发现在常温下本模型和经典模型计算值均能较好地预测纳米流体的热导率,但在温度较高时本模型与实验值更接近,表明其更适用于计算不同温度下纳米流体的热导率.在此基础上,讨论了温度、纳米颗粒体积浓度和粒径对纳米流体热导率的影响,以及在不同温度下纳米颗粒及基液两者对增大纳米流体热导率的贡献.%By analyzing the heat transfer mechanism of nanofluids based on the small scale effects of nanopartides,a predictive model of the effective thermal conductivity of nanofluids was developed.By comparing with experimental data and the classical models,it was found that at room temperature both the proposed model and the classical models exhibited good performance in predicting the thermal conductivity of nanofluids,but at higher temperatures the prediction values of the proposed model fit the experimental values better,indicating that it is more applicable for calculating the thermal conductivity of nanofluids at different temperatures.On this basis,the influence of temperature,volumetric concentration and particle size of nanoparticles on the nanofluid thermal conductivity was discussed,together with the contribution of both the nanoparticles and the base fluid to the thermal conductivity enhancement of nanofluids at different temperatures.