充满多孔介质的方腔内双扩散自然对流格子Boltzmann模拟

Lattice Boltzmann Simulation of Double Diffusive Natural Convection in a Square Enclosure Filled With Porous Medium

采用格子Boltzmann方法,对4个壁面均为低温、低浓度,内置高浓度发热圆的充满均匀多孔介质的方腔内双扩散自然对流现象进行了数值模拟研究.分析了Darcy(达西)数Da(10-4≤D_a≤10^(-2))和浮升力比B(-5.0≤B≤5.0)对内部发热圆表面平均Nusselt(努赛尔)数Nuav和平均Sherwood(舍伍德)数Shav的影响.模拟结果表明:除B=-1.0时,Nu_(av)和Sh_(av)随D_a的增加而增大;当-5.0<B<5.0,在D_a=10^(-4)时,Nu_(av)和Sh_(av)几乎不受B变化的影响;在Da=10^(-3)和Da=10^(-2)时,Nu_(av)和Sh_(av)随B的增加先减小后增大,在B=-1.0时取得最小值.

T he lattice Boltzmann method was adopted to investigate the double diffusive natural convection in a square enclosure filled with porous medium. T he temperature and concentration on surrounding walls were lowand those on the inner heat cylinder surface were high. T he influences of D arcy number Da（ 10^-4≤ Da≤ 10^-2） and buoyancy ratio B（- 5. 0 ≤ B ≤ 5. 0） on average Nusselt number Nuavand Sherwood number Shavon the heat cylinder surface were studied. T he results indicate that both Nuavand Shavincrease with Daexcept for the case of B =- 1. 0,and both Nuavand Shavare almost independent of B for D）a= 10^-4. Both Nuavand Shavfirst decrease and then increase with B increasing from- 5. 0 to 5. 0for Da= 10^-3and 10^-2 and reach the minimal value for B =- 1. 0.