关键词: 成核, 相变, 八水氢氧化钡, 稳定性, 复合材料

Abstract: Pure barium hydroxide octahydrate has some problems such as super-cooling, phase separation and volume change, so it needs to be further improved. According to the nucleation mechanism of the phase change material, the composite phase change materials, with 95.1% Ba(OH)₂·8H₂O+2%Ba(OH)₂·H₂O+2.9%H₂O, were prepared by using the barium hydroxide octahydrate as the base material,the barium hydroxide monohydrate and deionized water as compound additives. The thermal performance test of the composite phase change material showed that the thermal conductivity coefficient was 1.2W/(m·K),and the latent heat was 263.7kJ/kg. During the melting process of composite phase change material,temperature-pressure test was carried out. The relative pressure inside the container was less than 0.09MPa. The melting/solidification cycle experiment of the composite phase change material was conducted 300 times in the thermostatic bath. The test data showed that the super-cooling degree of the composite phase change material increased to 0.7℃,and the phase change latent heat decreased by 0.796%. The composite phase change material has suitable melting temperature and stable thermal performance, so it can be widely applied to the phase change thermal energy storage system.

Key words: nucleation, phase change, barium hydroxide, stability, composites