A Computational Model Of Silica Aerogel
Silica Aerogel in Insulation is one of the most outstanding insulating materials ever developed. Its unique combination of exceptional properties has attracted the attention of both the scientific world and the engineering community. Its main characteristics are its very low bulk density (0.1 g/cm3), very high porosity, a large specific surface area (1000 m2/g), optical transparency in the visible spectrum (99%), low refractive index (1.05), and acoustical properties with sound velocity reduced to 100 m/s, which is much lower than that of air.
These properties make silica aerogels very attractive for a wide range of applications including thermal insulation in the aerospace industry. To achieve the required temperature resistance, a special manufacturing process is needed. In this case, a combination of sol-gel chemistry and supercritical drying technology is applied.
The special manufacturing process results in a silica aerogel with a 95% porosity that is initially filled with the solvent, ethanol. Since ethanol has a strong surface tension that would otherwise compromise the porosity, it is necessary to remove it from the aerogel. This is accomplished using a computer controlled evaporation microwave oven and a three-meter-high vacuum pump. This allows the production of large quantities of silica aerogel at a very high purity and without compromising the physical properties of the material.
Another feature of the silica aerogel is that it has a closed porous structure with very few pores of diameter greater than 10 nm. As a result, it is very easy to handle and work with. This contrasts with other insulating materials that have open or unstructured pores, which make them more fragile and difficult to work with.
In order to further optimize the physical properties of silica aerogels, it is important to understand how these properties are influenced by the geometry of the porous network. This is why a computational model has been developed to help design structures with optimal performance for a variety of applications.
The model is based on the assumption that the thermal conductivity of the material is proportional to its volume and that the pore structure determines its permeability. The results of the simulations show that, for a given geometry and doping level, the geometry of the pore network can significantly influence the material's thermal conductivity. Furthermore, the model suggests that a more dense porous structure can be achieved by increasing the size of the pore openings. This could be an important step toward achieving the high thermal insulation needed in the aerospace industry. It also opens the door for the development of multifunctional silica aerogels with tailored properties that can be used in a wide range of military applications. The need for such high-performance technical products is growing as militaries strive to adapt their equipment to meet modern war needs. This includes the need for protective clothing that provides not only thermal insulation but also infrared shielding and stealth. Multifunctional silica aerogels can provide all of these functions at once in a single material, which is an exciting possibility for the future.