摘要
为制备一种稳定性好,过冷度低,导热性强且易于用泵输的相变乳液,研究采用超声乳化法,在石蜡(RT55)相变乳液中加入不同质量分数的纳米碳化硅,制备了一种改性相变乳液(SiC/PCME),并对其粒径分布、相变行为、导热性能、热响应速度及流变性能进行了研究.结果表明,当SiC添加量为0.09％(质量分数)的SiC/PCME稳定性最好,其体积平均粒径大小为480 nm,分别静置20天和经120次冷热循环前后粒径分布无明显变化;DSC测得0.09％(质量分数)的SiC/PCME的潜热值为39.0 J/g,过冷度仅为0.03 ℃,较未改性PCME降低了11.8 ℃,且经过120次循环过冷度不变,具有良好的循环热稳定性;55 ℃时,SiC/PCME的导热系数达到4.247 W/m·K;SiC强化了相变乳液的导热能力,提高了其热响应速度;且剪切速度为100 s-1时,SiC/PCME最低粘度达到3 mPa·s.
Abstract
In order to prepare a pumpable PCME with high stability,low subcooling and high thermal conductiv-ity,a modified PCME was prepared by adding different mass fractions of nano-SiC to paraffin(RT55)emulsion(SiC/PCME).The sample of SiC/PCME was prepared by ultrasonic method.The particle size distribution,phase change behaviors,thermal conductivity,thermal response rate and rheological properties of SiC/PCME were investigated.The results showed that the volume average particle size of SiC/PCME with 0.09 wt％SiC was 480 nm,and there was slight change in the particle size distribution before and after 20 days and 120 ther-mal cycles.The latent heat value of 0.09 wt％SiC/PCME measured by DSC was 39.0 J/g,and the subcooling degree was only 0.03 ℃,which was 11.8 ℃ lower than that of unmodified PCME.The subcooling degree of 0.09 wt％SiC/PCME was hardly changed after 120 cycles,which had good cycling thermal stability.The thermal conductivity of SiC/PCME was reached 4.247 W/m·K at 55 ℃.The thermal conductivity of the PCME and thermal response speed were improved by the addition of SiC nanoparticles.The lowest viscosity of SiC/PCME was 3 mPa·s at the shear speed of 100/s.
基金项目
天府实验室碳中和科技创新基地建设项目(2021ZYD0099)
南充市校科技战略合作项目(SXHZ036)
南充市校科技战略合作项目(SXHZ017)
NETL
NSTL
万方数据