The Molecular Dynamic Study On Phase Changing Process Of Phase Change Material

Phase Change Materials, which are energy transfer mediums by heat reception orrelease, are used widely in solar energy, building energy conservation, industrialexhaust heat and textile industry.Molecular dynamics simulations are studied in this dissertation, which havebeen used to study the crystallization mechanism of glycerol/1,6-hexanediol mixtureand calcium chloride. The process can be characterized by three stages:1Under periodic boundary condition, molecular dynamics simulation isproceeding to investigate phase transition of mixture of glycerol/1,6-hexanediol indifferent ratio and different temperature in NPT system. By means of relation ofmolecular self-diffusion coefficient/specific volume and temperature, phasetransformation temperatures of different mixture systems are gotten; at the same time,influencing factors on phase transition temperature are also analyzed, such as materialcompatibility, molecular arrangement in phase transition, molecular structure,components and so on.2Amorphous silica is used to absorb mixture of glycerol/1,6-hexanediol, andits adsorption property depends on the existing of silanol hydroxyl; radialdistribution function is applied to simulate adsorption ability. Through radialdistribution function, adsorption configurations of solid-liquid interface and particlediffusion under average pair potential or in solid-liquid interface are analyzed.3As inorganic phase-change material, phase change proceses of calcium chloridesolution are calculated under different temperature drop rates; meanwhile amorphoussilica is added as nucleating agent, moleculer configuration and correspondingstructure at the interface of nucleating agent and calcium chloride solution are alsostudied.