方腔内双扩散混合对流数值模拟

Numerical investigations of double diffusive mixed convection in enclosure

对内置发热圆的方腔内双扩散混合对流现象进行了数值模拟研究。发热圆位于方腔中心,流体从方腔左侧底部流进,右侧顶部流出。首先,分析了在不同Richardson数Ri下方腔内的流动特性,发现Ri=0.001时方腔内部流动出现了振荡现象,而Ri=1.0时流动处于稳定状态。其次,研究了流动处于稳定状态时,Lewis数Le及浮升力比Br对方腔内双扩散混合对流的影响,得出平均Nusselt数Nuav和平均Sherwood数Shav随着Le及Br的变化规律,可为空间内部污染物处理、热舒适性研究以及烟气控制等提供理论参考。

The double diffusive mixed convection around a heated cylinder in an enclosure was numerically studied.The heated cylinder was located at the center of the enclosure with high temperature and concentration.The inlet flow with low temperature and concentration was located at the lower-left wall of the enclosure and the exit was at the upper-right wall.First,the influences of Richardson number(Ri)on the interior flow characteristics were presented.It showed that the oscillation phenomenon occurred at Ri=0.001.At Ri=1.0,the flow was in a steady state.Then,the influences of Lewis number(Le)and buoyancy ratio(Br)on the double diffusive mixed convection were investigated while the Richardson number was kept constant at 1.0.The average Nusselt number Nuavand Sherwood number Shav were reported.The current study can provide the theoretical supports for the pollutant control,thermal comfort or smoke control in space.