Research On The Flow And Heat Transfer In Porous Media Based On Lattice Boltzmann Method

Blunt body forms are widely used in life,such as bridge piers,housing construction,etc.When fluid flows through these bodies,the flow around the flow field is changed due to the existence of blunt bodies,resulting in a series of aerodynamic problems of blunt bodies.Fluid flow is often accompanied by complex heat exchange,and its research is of great significance for theoretical development and practical application in related fields.As a new numerical simulation method developed for the last thirty years,the lattice Boltzmann method has the advantages of simple algorithm and high parallelism.It has been applied to many fields of fluid mechanics and thermodynamics.In this paper,the progress in the study of flow around a blunt body at home and abroad is reviewed.The numerical simulation of the flow around a blunt body of a columnar body and the natural convection heat transfer in a porous medium is simulated by using the lattice Boltzmann method.The important work is as follows:Starting with the continuous Boltzmann equation,the lattice Boltzmann-BGK equation is derived by discrete time,space and velocity,and the relation between the macroscopic physical quantity and the boundary condition and the lattice Boltzmann method is established.Through the improvement of the basic model of lattice Boltzmann method,the lattice Boltzmann method is applied to the study of heat transfer.A program language processing method for complex geometric boundaries is proposed.The accuracy of the method is verified by simulating the flow around a single column.The simulation of the flow around a single column shows that Re has an important influence on the shape of the flow field and the size of the lift drag.The simulation of the relationship between the flow field and the spacing of the columns shows that when the column spacing is less than 1.0 times the length of the square column,the flow field shows the state of the flow around a single column,and the space between the square columns is greater than the square column of 3 times.On the side,the square columns form stable Carmen vortex street.Further simulation of the convective heat transfer in the porous medium of the closed square cavity and the Sierpinski carpet fractal structure shows that the Ra number has an important influence on the natural convection heat transfer mechanism.The heat transfer is mainly heat transfer in the Ra number,while the heat transfer is mainly convective heat transfer when the Ra is larger,and the results of the porous medium convection simulation show that Re The larger the number,the better the effect of convection heat transfer;and the increase of the inlet speed can also achieve the purpose of enhanced heat transfer.For the fractal structure of different orders,the higher the order is,the greater the heat transfer area is,but for the final heat transfer effect,the 3 order fractal structure is the best choice within the scope of the study.