Numerical Simulation Of Multi Physical Field Coupling In Porous Media

Porous media materials have the characteristics of low density,large specific surface area and complex structure.The specific surface area makes it possible to carry out rapid and effective heat exchange inside the porous media materials,which is valued by more and more scholars.It is the most efficient way of thermal protection to use porous media materials for sweat cooling on the surface of high-speed aircraft,but it is difficult to use it The complex internal structure also brings great difficulty to the research itself,so it is necessary to analyze the cooling performance and strength performance of porous media materials.In this paper,titanium alloy is used as porous medium material,which has the advantages of good heat transfer effect and high strength.The simulation results show that with the increase of coolant flow rate,the blue area in the temperature distribution cloud gradually increases.When the coolant flow rate increases to an appropriate value,a thin film will be formed above the porous medium,When the temperature inside the film changes dramatically,the porous medium area is separated from the high temperature area,and the three kinds of cooling media can effectively cool the upper surface of the porous medium material at a very small flow rate.Finally,the heat transfer of air and water as the cooling media is simulated,and it is found that the better the heat transfer effect is with the gradual increase of the mass ratio of water,The closer to water,the better the cooling effect.When water is used as cooling medium,the phase change position of water will gradually move up with the increase of flow rate.Under the same mass flow rate,the cooling effect of water is far greater than the former two.When the steady state is reached,the water vapor will be evenly distributed on the upper part of the porous medium,effectively protecting the porous medium area.At the same time,it is also found that when water is used as the cooling medium,the thermal concentration will occur at the leading edge of the porous media material contacting with the high-temperature mainstream.This is because the velocity direction of the cooling medium at the leading edge is vertical,while the direction of the high-temperature mainstream is horizontal,which can not effectively block the high-temperature mainstream.In order to solve this problem,this paper simulates the cooling situation under different inclination angles,and finds that when the inclination angle is 30 °At the same time,the cooling efficiency of the contact front increases from 34% to 66%,and the phase transition interface is smoother.Then,the cooling effect of porous media with different porosity and pore size is simulated.Based on the above simulation results,the temperature distribution and pressure distribution of the cooling scheme with cooling efficiency higher than 80% are applied to the established porous medium model as boundary conditions to calculate the stress.The simulation results show that the stress is mainly affected by the temperature distribution,and the pressure distribution has little effect.