Experimental and numerical investigation of phase change progress for paraffin in hybrid aerogel of graphene and carbon nanotubes

In this work, the phase change progress of paraffin filled hybrid aerogel of graphene and carbon nanotubes was investigated by numerical simulation. Volume averaging method and thermal equilibrium equation were used to simulate melting and solidification process. The trend of experimental and simulated temperature-time curves had good consistency. The phase change process of paraffin in graphene aerogel (GA) was much slower than that in graphene-carbon nanotubes aerogel (GCA). When the effective thermal conductivity of paraffin/GCA (PGCA) phase change composites was not significantly different, the local heat transfer mainly related to the effective thermal conductivity. However, the overall heat transfer was greatly affected by porosity. Low porosity indicated more content of GCA skeleton and less paraffin. On one hand, sufficient contact between GCA skeleton and paraffin promoted heat transfer. On the other hand, the decrease of latent heat energy of paraffin made temperature rise or fall rapidly during phase change process. The simulation results demonstrated the discrepancies in the heat transfer performance of GCA skeleton with different effective thermal conductivity and porosity, which can be applied to temperature management and accelerated heat transfer.