Numerical simulation on thermal performance of vacuum insulation panels with fiber /powder porous media based on CFD method

Up to now, the fiber/powder porous media is getting more and more attention as a new development direction in the field of vacuum insulation panels. In this paper, the random generation-growth method is used to generate the structure of the fiber/powder porous media. The numerical simulation method is used to simulate the thermal conductivity of the fiber/powder porous media based on Fourier's law to study the correlation between the effective thermal conductivity and the microstructure of the fiber/powder porous media under vacuum conditions. The model was verified with experimental and theoretical data. The effect of different microstructure parameters such as powder diameter and fiber orientation angle on the effective thermal conductivity of the fiber/powder porous media is introduced in detail. The results show that the finer the diameter of the powder leads to the smaller the pore size of the fiber/powder porous media and has the stronger the ability to maintain a lower effective thermal conductivity under higher pressure. In addition, the more inconsistent between the fiber axial direction and the heat transfer direction, the better the thermal insulation performance. The results are very important for the optimization of the core material of the vacuum insulation panel.