Study On Thermal Insulation Performance Of Foam Metal And Ternary Aerogel Composite

As a new material,Because of its multi-nanometer pores,low density,and good thermal insulation properties,aerogels are widely used in various fields of life,especially in the field of thermal insulation of spacecraft.However,aerogel has poor mechanical properties,is relatively brittle,and has a low degree of stress,so it cannot be used directly as a thermal insulation material;Foam metal has the characteristics of low density,low thermal conductivity,excellent mechanical properties and high temperature resistance.Compared with aerogel,it is greatly affected by radiation and has higher thermal conductivity.Combining the characteristics of these two materials,the aerogel and foam metal are compounded to prepare a new type of thermal insulation material with good thermal insulation performance.In this paper,the numerical simulation method is used to study the Al2O3_SiO2_ZrO2 multi-component composite aerogel with Al2O3 aerogel as the main body,Foam nickel,Al2O3_SiO2_ZrO2 multi-component composite aerogel/foam nickel composite thermal insulation performance.Using comsol software to build a stick model,Simulated heat transfer analysis of SiO2 aerogel,Zr02 aerogel,Al2O3 aerogel and Al2O3_SiO2_ZrO2 multi-component composite aerogels with different ratios of n(Al):n(Si):n(Zr)were carried out.The best molar ratio of thermal conductivity is 12:4:2.Compared with the pure Al2O3 aerogel,the effective thermal conductivity of the composite aerogel at this ratio decreased by 27.5%at 300K,and by 8.59%at 1500K,and by 49%at 2100K.The face-centered model is used as the nickel foam characterization model.Ignoring the convective heat transfer in the pores,when the porosity is maintained at around 0.95875,the gas phase thermal conductivity and radiant thermal conductivity at 300K account for 18.4%and 36.6%of the overall thermal conductivity,respectively.The total proportion is as high as 55.2%;The effective thermal conductivity at 1500K is 2.725W/(m.K),of which the radiant thermal conductivity accounts for about 97%of the overall thermal conductivity.Established a simplified model of foamed nickel-multicomponent composite aerogel,When the foam nickel porosity is maintained at 0.95875,Without considering the pore structure of the composite aerogel,a composite aerogel with a porosity of 0.938 is used to completely fill the nickel foam.The effective thermal conductivity of the overall composite material at 300K is 0.02654W/(m.K),which is 62.51%lower than that of nickel foam.At 1500K,the temperature decreased by 95.67%,and after the porosity of nickel foam was greater than 0.96,the filling effect was basically similar.