Phase Change And Heat Transfer Behavior Of Paraffin In Carbon Aerogel

With the development of society,economy and science and technology,energy demand has become increasingly important.As a kind of energy storage material,phase change material?PCM?has good environmental protection and sustainability advantages.It can absorb or release energy through the melting and solidification process for energy recycling to improve energy efficiency.At present,PCM has been widely used in energy storage and temperature management.As a phase change material,paraffin has the advantages of high latent heat,no toxicity,no corrosion,good chemical stability,and low cost.However,its low thermal conductivity slows down the heat transfer process,resulting in slow energy storage.Paraffin adding into thermally conductive skeleton can accelerate the heat transfer process and increase the speed of energy storage.In this paper,paraffin was used as the phase change material,and carbon aerogel was used as the thermal conductive skeleton material.The phase change and heat transfer behavior of the paraffin in the carbon aerogel were experimentally and numerically simulated.Phase change and heat transfer behavior of paraffin in graphene aerogels was investigated.A numerical model was established,and the experimental test results were compared with the numerical simulation results.The parameter configuration in the simulation was adjusted,a reasonable numerical simulation setting was obtained,and the characteristics of phase change and heat transfer during melting and solidification were analyzed.Studies show that the heat transfer method of paraffin/graphene aerogels was mainly heat conduction,and the phase change process was affected by porosity and pore size.In order to further study the phase change and heat transfer behavior of paraffin in graphene aerogels,different content?0%,5%,10%?of ethylene-vinyl acetate copolymer?EVA?was added to paraffin,and the polymer was discussed.Effect of paraffin phase change and heat transfer behavior in graphene aerogels.Studies have shown that the addition of EVA had little effect on the phase change and heat transfer behavior of paraffin in graphene aerogels.EVA can hinder the flow of liquid paraffin,and because the thermal conductivity of polymer was slightly larger than paraffin,the heat transfer of paraffin also slightly accelerated.To further investigate the effect of thermally conductive skeleton on the phase change and heat transfer behavior of paraffin,paraffin in hybrid thermally conductive skeletons of graphene-carbon nanotube aerogels?GCA?with different proportions?carbon nanotubes:graphene=2/1,1/1,1/2?were investigated.Studies have shown that the thermal conductivity of a single graphene aerogel was weaker than that of hybrid thermal conductive skeletons of carbon nanotube-graphene aerogel.The relatively small content of paraffin in the GCA_1/1 made its latent heat energy slightly lower.The heat transfer of GCA_1/1 was faster than that of GCA_2/1 and GCA_1/2.