Study On Performance And Application Simulation Of SiO₂/Al₂O₃ Microporous Powder Vacuum Insulation Material

China is a large energy-consuming country.With the increasing shortage of non-renewable energy in the world,for industrial kilns with high energy consumption in steel,cement,glass,ceramics,power and other industries,utilization of superior thermal insulation materials on kilns is the most direct and effective way to save energy,improve the energy utilization efficiency,and reduce energy consumption.The microporous powder heat insulation material has a porous structure co-formed by the micro-powders and fibers.The vacuum insulation material made by vacuum packaging has more excellent insulation performance,with great potentialIn this thesis,SiO₂/Al₂O₃ microporous powder is used as the matrix,Zr O₂ fiber is used as the reinforcing fiber,TiO₂ powder is used as the opacifier.Then the composite is pressed into a block core material by a dry molding process,and then vacuum-sealed by aluminum foil.The effects of the density of the core material,the amount of TiO₂opacifier and the degree of vacuum on the performance of SiO₂/Al₂O₃ composite microporous powder vacuum insulation materials are also discussed in detail,In addition,a high-temperature test furnace is established to evaluate the thermal insulation performance of the experimentally prepared SiO₂/Al₂O₃ composite microporous powder vacuum insulation material,and uses COMSOL software to simulate the steady heat transfer of the test furnace and analyze the performance of powder vacuum insulation materials.The main conclusions are as follows:?1?The thermal conductivity of the composite microporous powder thermal insulation materials with different densities will be changed after vacuum packaging.After vacuum packaging,the degree of thermal conductivity reduction of thermal insulation material increases first and then decreases with the increase of density.When the core material density is 0.62g/cm³,vacuum packaging has the most significant effect on the thermal conductivity of the material,and the thermal conductivity changed from 0.063W/m·K to 0.054W/m·K.?2?The effect of the amount of TiO₂ on the thermal conductivity of the microporous powder material before and after vacuum packaging shows that when the mass fraction of TiO₂ is 5wt%,the vacuum packaging has the biggest influence on the thermal conductivity of the sample.The thermal conductivity reduced from0.060W/m·K to 0.045W/m·K after encapsulation,the degree of reduction is 25.0%;as the TiO₂ content increases from 5%to 15%,the degree of influence of vacuum packaging on the thermal conductivity of the sample has a decrease,from 25.0%to13.3%.?3?The influence of vacuum degree on the thermal conductivity of microporous powder vacuum insulation materials shows that as the vacuum degree increases,the thermal conductivity of the sample gradually decreases and then tends to be stable.The appropriate vacuum degree is 1.5 k Pa.?4?The effect of temperature on the thermal conductivity of the microporous powder thermal insulation material before and after vacuum packaging shows that the vacuum packaging has the greatest impact on the thermal conductivity of the sample at200°C,with a reduction of 25.0%,but at 400°C and 600°C the vacuum structure of the package has been impaired,and the thermal conductivity of the sample just decrease a little by about 5%.?5?The application comparison of thermal insulation materials in high temperature test furnaces shows that when the materials are microporous powder vacuum insulation materials,the cold surface temperature in the high temperature test furnace is only 128°C,and the heat dissipation of the cold surface is only 53W;Under the same conditions,when the aluminum silicate thermal insulation fiber is the insulation layer,the cold surface temperature is 272°C,and the heat dissipation is 80W.The results show that the thermal insulation performance of the microporous powder vacuum insulation material is more significant.The COMSOL software was used to simulate and analyze the heat transfer of the high-temperature test furnace.The effect of the composite microporous powder vacuum insulation material on the temperature field distribution of the high-temperature test furnace was studied,and the excellent thermal insulation of the microporous powder vacuum insulation material was proved.