Research On Graphene Modification Of Phase Change Composite Used In Flight Vehicle And Heat Transfer

Phase change material（PCM）can absorb a lot of heat and stay at certain temperature while melting,which shows great prospect in the field of flight vehicle.But the thermal conductivity of PCM is not high,when used in thermal management of flight vehicle,it cannot transmit heat to other section timely,which leads to temperature rising of object that needs thermal control.In order to solve this problem,this paper usesgraphene with high thermal conductivity and low mass to enhance heat transfer of PCM.This paper prepares graphene foam via vacuum filtration,and studiesthe effect of raw material,solvent,disperser,preparation of dispersion liquid and the rate of filtrationon the structure of graphene foam,by which the preparation method and technology was ascertained.Then the pore structure,thermal conductivity,mechanical property,XRD and Raman areanalyzed.Utilizing the prepared graphene foam as skeleton,this paper prepares the graphene foam with melting infiltration method.the vacuum infiltration-atmospheric pressure solidification,as well as infiltration temperature of 70 degree centigrade and infiltration time of 1 hour are ascertained.The infiltration rate of as prepared GF/P reaches 83.3%,in panel thermal conductivity reaches 10.17Wm^-1K^-1,which is 39.7 times higher than pure paraffin.DSC shows the latent thermal energy is 178.26J/g,and the temperature of phase change is 53.8℃.The GF/P has excellent thermal stability,the mass loss rate is 0.7%after 10 thermal cycles.SEM shows goof contact between graphene and paraffin.XRD shows no new phase structure was generated.Byanalyzing the GF/P with effective media theory,this paper obtains the equation of effective thermal conductivity.Based on thermal management of instrument cabin in flight vehicle,numerical simulation is used to find the factor that affects heat transmit,thedirection of heat flux should be aligned to direction of graphene sheets to obtain best result.With the help of thermal response test platform,the numerical simulation result was verified.