针对纯石蜡(正十八烷)作为固-液相变储能材料存在导热系数小、传热性能差的缺点,采用两步法制备了铜纳米粒子质量分数分别为0％、0.1％、0.2％、0.5％、1％、2％的铜纳米粒子/正十八烷复合相变材料,并对其热物性进行了实验研究.采用瞬态热针法测量复合相变材料的导热系数.实验结果表明,铜纳米粒子可有效提高正十八烷的导热系数.利用DSC对铜纳米粒子/正十八烷复合相变材料进行热分析,结果表明,体系中添加铜纳米粒子后正十八烷的相变温度变化很小,而体系的相变潜热随铜纳米粒子质量分数的增加而逐渐减小,但减小幅度不大,因此铜纳米粒子的加入对正十八烷的蓄热能力影响较小.另外,对铜纳米粒子质量分数为1％的铜纳米粒子/正十八烷复合相变材料的热稳定性进行研究,结果表明其具有良好的热稳定性.%Based on paraffin wax (octadecane) as a kind of solid-liquid phase change materials (PCMs) having the disadvantages of low thermal conductivity and bad heat transfer performance, octadecane/copper nano-particles composite PCMs were prepared by two steps and their thermal properties were measured. The mass fraction of copper nano-particles in PCMs is 0. 1%, 0. 2%, 0. 5%, 1% and 2%, respectively. Transient hot probe method was used to measure the thermal conductivity of PCMs. The results show that copper nano-particles can effectively improve the thermal conductivity of octadecane. Thermoanalysis measurement was finished by differential scanning calorimetry (DSC) analysis techniques. The results show that the phase-transition temperature of octadecane which is added with copper nano-particles changes little, while the latent heat of the composite PCMs gradually decrease with the increasing mass fraction of copper nano-particles, but decrease slightly. Therefore copper nano-particles have less influence on the heat storage capacity of octadecane. Finally, the heat stability of octadecane/copper nano-particles composite PCMs which contain 1 % copper nano-particles was studied by DSC analysis techniques. The results show that latent heat and phase-transition temperature of composite PCMs do not obviously decrease with the increasing number of thermal cycles, demonstrating that composite PCMs have good thermal stability.
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