Simulation Of Convection Heat Transfer In Porous Media Based On Thermal LB Model

The flow and heat transfer phenomena are common in porous media and in engineering practice.The study of flow and heat transfer in porous media has important theoretical significance and engineering application value.First of all,this paper uses LB method to simulate the convection heat transfer in a two-dimensional square cavity.the effect of heat source location,size and number on characteristics of local heating at the bottom of the porous media the convection heat transfer is discussed.the simulation results show that the heat source location,size and number on characteristics of the convection heat transfer in porous medium and at the bottom of the local heating have a great impact,.there exists an optimum heat source location,size and number to make the characteristics influence of the convection transfer to the maximum under certain conditions.Second,this paper studies the effect of Darcy number,Rayleigh number,porosity and other characteristic parameters on the local heating characteristics of porous media at the bottom.the simulation results show that:(1)Da and Ra can enhance the convective heat transfer of the cavity.the critical length of heat source is affected by Da and Ra;(2)the change of porosity on the effects of the convection heat transfer in a square cavity are divided into two situations: in the case of a,the effect of porosity on the average Nusselt number is significant.In the case of b,the porosity of the impact is not obvious;the porosity change will also affect the size of the critical length heat source.Finally,the LB method is used to study the biological filter flow nonuniformity.filter the number and position of entrance,entrance velocity ratio and width ratio,distribution of porous medium,to reduce the effects of non-uniform flow are discussed in detail.Simulation results show that under certain conditions,the 2 model is better than the 1 entrance entrance and the 3 entrance model and has the best speed ratio and relative width than the entrance flow biofilter optimal;porous media from the middle to both sides by the linear distribution can make the flow heterogeneity of biological filter to improve.