Basic Research On Infrared Digital Camouflage Based On Metal Foam And Phase Change Materials

With the development of infrared camouflage technology and infrared detection technology,infrared camouflage under multi-band detection cannot be realized only by the traditional infrared camouflage means of controlling the target emissivity.The continuous updating of infrared imaging detection equipment further increases the space detection rate and spectral resolution of the system,which leads to a lot of difficulties and challenges for target equipment in infrared camouflage.Therefore,it is necessary to use different camouflage methods to make the infrared radiation characteristics of the target equipment are consistent with the background.In this paper,foam metal composite phase change materials were studied from two aspects: software simulation and experimental research.Phase change materials with different phase transition temperatures and aluminum foam with different porosity were used to control the temperature by using two materials.Finally,an infrared camouflage method is realized to achieve the target infrared camouflage effect.Firstly,the foam metal aluminum material and the paraffin phase change material were selected to study the basic structure and thermodynamic properties of the two materials.Then theoretically discuss the equivalent thermal conductivity of the two materials after compounding,which proves that the temperature of the target can be controlled by using two materials.In order to study the temperature control effect of the combination of foam metal and phase change material,the single crystal structure of foam metal was designed by ANSYS software based on the microstructure of metal foam.Then based on the thermal properties of the phase change material,a three-dimensional physical model of the foamed metal composite phase change material was established.The finite element simulation of ANSYS software was carried out to analyze the heat transfer characteristics of foam metal with different porosity and phase change materials,and the effect of foam metal was evaluated by comparison with pure phase change materials without foam metal.The simulation results show that the heat transfer performance of the phase change material is closely related to the porosity of the foam metal.The use of metal foam can greatly increase the heat transfer rate of phase change materials,but the effect of foam metal with different porosity is different.The smaller the porosity of the foamed metal,the faster the temperature change of the composite phase change material during heat transfer,and the phase change process of the phase change material will be shortened to some extent.By observing the temperature distribution cloud map of the model,it can be seen that the use of foam metal can not only improve the heat exchange capacity of the phase change material,but also make the temperature distribution of the phase change material more uniform during heat transfer.Finally,based on the simulation results,the role and effect of foam metal in the temperature control ability of phase change materials were studied experimentally.Three typical foam metal aluminums(Three dimensional mesh aluminum foam,Spherical aluminum foam with open pores,Micro porous aluminum foam)and phase change paraffin materials with different phase transition temperatures(32??42??46?)were selected.These materials are used to prepare composite phase change materials of different combinations.The effects of different porosity of aluminum foam on paraffin materials were studied by designing different experiments.The experimental results show that the difference in porosity makes the phase change material have different temperature control time,and the experiment verifies the correctness of the software simulation analysis results.Finally,a randomly distributed foamed aluminum composite phase-change paraffin material was designed and observed by infrared thermal imager.It can be seen that different regions exhibit differences in brightness,resulting in an infrared distribution of digital camouflage,demonstrating the ability to achieve a camouflage effect of infrared digital camouflage by using different composite phase change materials.