EFFECT OF HIGH THERMAL CONDUCTIVITY ION CONTENT ON THE THERMAL CONDUCTIVITY OF BLAST FURNACE SLAG-BASED LOW-TEMPERATURE PHASE CHANGE MATERIALS
The effects of graphene mass percentage content at different temperatures on the structure,phase transition and energy of blast furnace slag-based low-temperature phase change materials were studied by molecular dynamics simulation.The changes of C-H and C-C bond length,H-C-H bond angle,C-C-C torsion angle of carbon chain,terminal distance of alkane molecules,energy in the system and radial distribution function(RDF)of the system were systematically analyzed during the heating process of C28H58,C22H46 and graphene molecules,and the phase transition temperature of each system was determined according to the relationship between the self-diffusion coefficient and the temperature of the system.The results show that the C-H bond length is the most stable at 1.106 Å in the range of 280～320 K,the bond length of C-C bond is elongated from 1.537 Å to 1.539 Å,the stability of C-C bond in the alkane system is slightly smaller than that of C-H bond,the boundary effect of graphene cannot be ignored,and the boundary effect of graphene is weakened in the temperature range of 320～350 K,and the influence of graphene on the H-C-H bond angle of alkanes is less in the range of 280～350 K.With the increase of graphene,the phase transition temperature of the system gradually decreases,and when the added mass is 8％of the alkane mass,the phase transition temperature of the system begins to decrease rapidly,and the addition of graphene increases the order of the system by radial distribution function(RDF),and the thermal conductivity increases by 72％when the mass fraction of graphene is 10％.
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