石蜡基纳米金属复合相变材料热性能的实验研究

Experimental study on thermal properties of nanometal-paraffin composite phase change materials

以石蜡为复合相变材料的基体,分别添加氧化铜、二氧化硅和氧化锌的纳米颗粒通过两步法制备多种石蜡基纳米金属复合相变材料。通过改变所添加纳米金属颗粒种类、质量分数和颗粒粒径,对比分析实验模型内复合相变材料蓄放热过程的温度曲线,来探究以上参数对复合相变材料热性能的影响。结果表明,通过添加纳米金属颗粒的方式能够有效提升石蜡的蓄放热性能,添加氧化铜颗粒的效果要优于氧化锌颗粒和二氧化硅颗粒;复合相变材料的导热系数和动力黏度均随颗粒浓度的增加而增大,两者共同决定着复合相变材料的换热过程能否被强化;纳米金属颗粒的粒径越小,越有利于增强对复合相变材料的热性能,添加30 nm粒径纳米颗粒相对于100 nm粒径纳米颗粒蓄热速率能提升26%,放热速率能提升41%。

With paraffin as the matrix of the composite PCM,the nanometal-paraffin composite phase change materials(PCMs)were prepared by a two-step process by adding the nanoparticles of copper oxide,silicon dioxide and zinc ox.ide respectively.The thermal performance factors of composite P CMs were studied by changing the types of nanometal particles,the percentage of addition and the particle size and making a contrastive analysis of the temperature curve of the heat storage and release process of the composite phase change material in the experimental model.The results show that the heat storage and release performance of paraffin wax can be effectively improved by adding nano-metal parti.cles.The effect of adding copper oxide particles is better than that of zinc oxide particles and silica particles.The ther.mal conductivity and dynamic viscosity of the composite PCM increase with the increase of the particle concentration,which together determine whether the heat transfer process of the composite PCM is strengthened.The smaller the parti.cle size of the nanometal particles,the more favorable it is in enhancing the thermal property of the composite PCM.Add.ing 30 nm particle size nanometal particles to the composite PCM can increase the heat storage rate by 26%compared with the 100 nm particle size,and the heat release rate can be increased by 41%.