Design And Expertiment Of Integrated Thermal Protection Systems With Shaped Composite Phase Change Materials

The integrated thermal protection systems(ITPS)combines thermal protection and loadbearing functions with higher structural efficiency than traditional thermal protection systems(TPS).However,in the integrated thermal protection system,the properties of the insulating material and the load-bearing material are quite different.The difference in material properties leads to the fact that ITPS has obvious thermal bridge effect at the web,which limits the engineering process.Based on the principle of heat bridge phenomenon,a new integrated thermal protection structure(PCM-ITPS)with shaped composite phase change materials layer is designed,which utilized from the high specific heat capacity of the phase change material.After verifying the excellent performance of the PCM-ITPS,a set of processes,which is based on Python,was developed to optimize the structural parameters for the specific working conditions,achieving the lightweight design of PCM-ITPS.In this paper,the causes of the thermal bridge phenomenon of the integrated thermal protection system are analyzed by the heat transfer.Starting from the basic principle of heat transfer,the phase change material which is different from the traditional insulation material is proposed to mitigate the effect of the thermal bridge effect.The PCM-ITPS was simulated to analyze its thermal protection properties and the influence of parameters such as phase change layer thickness on its thermal protection performance.The results show that the phase change material placed on the bottom face sheet of the PCM-ITPS structure can absorb the excessive heat load introduced by the thermal short circuit effect and improve the thermal protection performance of the thermal protection system.On this basis,the sequential thermal-mechanical coupling simulation is used to verify the bearing performance.The traditional one-dimensional equivalent thermal resistance calculation method can not simulate the internal temperature field of the sandwich panel.A new calculation method that accurately simulates the internal temperature distribution of the panel sandwich.The two-dimensional temperature field interpolation is used to generate the three-dimensional temperature field.Through the thermal coupling simulation,the load-bearing properties of PCM-ITPS such as stress and deformation were calculated.The thermal buckling analysis was carried out for PCM-ITPS to understand the bearing capacity and structural stability of PCMITPS in detail.After verifying the performance of PCM-ITPS by simulation,the test sample was made.The traditional phase change material such as parrfin is easy to leak,and the composite phase change material based on porous material is prepared,which solves the disadvantages of the traditional phase change material requiring additional packaging.Detailed material performance tests were carried out on the finished materials.PCM-ITPS test pieces were prepared for the PCM-ITPS design,and the important protection capabilities of the PCM-ITPS structure were verified by test.The experimental results verify the feasibility of this new type PCM-ITPS and show that this new integrated thermal protection structure has better thermal protection ability.The last but not the least,this paper developed a set of optimization programe,which is based on Python.This programe takes the PCM-ITPS structural parameters as design variables,and the thermal insulation and load bearing performance requirements as constraints.Under the specific conditions,the PCM-ITPS scheme is carried out.Optimized design to achieve a lightweight design of the PCM-ITPS structure.The PCM-ITPS optimized by different global algorithms has a weight loss of 14.32% and 10.03%,and a reduction of 46.09% and 45.55%.Compared with the traditional ITPS scheme,the above work provides the necessary theory for promoting the design-manufacturing integration process of the thermal protection system.