Numerical Study On Natural Convection Of Cu-water Nanofluid In Porous Trapezoidal Cavity

The natural convection heat transfer in porous trapezoidal cavity widely exists in engineering application fields,such as material drying,chemical accumulation reaction bed,thermal energy storage,electronic equipment cooling and solar energy utilization.Due to the weak thermal conductivity of traditional liquids in porous media,the enhancement of natural convection heat transfer in porous trapezoidal cavity is limited.As a fluid with excellent heat transfer performance,nanofluid has received extensive attention.In addition,the natural convection heat transfer under the condition of partially cooled wall and linearly heated wall widely exists in many engineering application fields,such as electronic engineering,chemical engineering,and solar energy applications.In view of the importance of natural convection heat transfer phenomena in practical applications,the natural convection heat transfer of Cu-water nanofluid in porous trapezoidal cavity under the condition of partially cooled wall and linearly heated wall is studied numerically.The contents and conclusions of this paper are as follows:The natural convective heat transfer of Cu-water nanofluid in porous trapezoidal cavity is studied numerically.The right vertical wall of the cavity is heated,the left inclined wall is partially cooled,and the remaining walls are insulated.Three different partially cooled walls are considered.The partially cooled wall is located in the upper part of the inclined wall,adjacent to the top wall;the partially cooled wall is in the middle of the inclined wall;the partially cooled wall is located at the lower part of the inclined wall,adjacent to the bottom wall.With the length of partially cooled wall is certain,the effects of the aspect ratio,Rayleigh number,Darcy number and the volume fraction of nanoparticle on heat transfer are studied.The results show that the average Nusselt number on the right side increases with increasing Ra,Da and ?.As the position of partially cooled wall moves downward,the fluid flow intensity gradually decreases,and the convective heat transfer intensity decreases.When partially cooled wall is located at the lower part of the inclined wall,adjacent to the bottom wall;with the increase of the aspect ratio,the flow intensity gradually increases.The natural convective heat transfer of Cu-water nanofluid in porous trapezoidal cavity is studied numerically.The right vertical wall of the cavity is partially heated,the left inclined wall is partially cooled,the top wall is insulated,and the bottom wall is partially heated or insulated.The partially cooled wall is located in the upper part ofthe inclined wall and it is adjacent to the top wall.Three different partially heated walls are considered.With the aspect ratio is 0.50,the effects of ?,Ra,Da and the position of partially heated wall on heat transfer are studied.As Ra,Da and ? increase,the flow intensity and heat transfer rate are enhanced.The position of partially heated wall has a certain effect on the average Nusselt number.The natural convective heat transfer of Cu-water nanofluid in porous trapezoidal cavity is studied numerically.The right vertical wall of the cavity is linearly heated,the left inclined wall is partially cooled,and the remaining walls are insulated.The partially cooled wall is located in the upper part of the inclined wall which is adjacent to the top wall.With the linearly heated wall,the effects of Ra,Da and ? on heat transfer are studied.The results show that linearly heated right side wall has certain influence on the streamlines and isotherms of natural convection heat transfer of Cu-water nanofluid in porous trapezoidal cavity.The average Nusselt number on the right side wall increases with increasing with increasing Ra,Da and ?.