Soret和Dufour效应对方腔内双扩散自然对流影响的格子Boltzmann模拟

Lattice Boltzmann simulation of double diffusive natural convection with Soret and Dufour effects in enclosure

采用格子Boltzmann方法,并考虑双扩散过程中的Soret和Dufour耦合效应,对内置高浓度发热圆的方腔内双扩散自然对流现象进行数值模拟,高温高浓度发热圆位于方腔中心,四周壁面均为低温低浓度。在不同的浮升力比Br(-5≤Br≤5)、Soret数Sr(-0.4≤Sr≤0.4)和Dufour数Df(-0.4≤Df≤0.4)条件下,分析了方腔内部自然对流双扩散特性。研究结果表明:在相同的Br条件下,随着Sr和Df数同时增大,方腔内传热能力和传质能力均有所减弱;在相同Sr和Df数条件下,随着Br的增大,传热能力和传质能力均先减弱后增强。

Lattice Boltzmann method is adopted to investigate the characteristics of double-diffusive natural convection around a heated cylinder in square enclosure with coupled Soret and Dufour effects.The inner heated cylinder is located at the center of the enclosure and four surrounding walls are assumed to be low temperature and concentration.With different parameters of buoyancy ratio Br(-5≤Br≤5),Soret number Sr(-0.4≤Sr≤0.4)and Dufour number Df(-0.4≤Df≤0.4),the double-diffusive natural convective characteristics in the enclosure are analyzed.The results show that,at the same Br,and with the simultaneously increasing Sr and Df,both the heat and mass transfer capacities are weaken.At the same Sr and Df,the heat and mass transfer capacities are first weakened and then enhanced as Br increases.The simulation study of this physical model can provide the theoretical support for the analysis of indoor fire and pollutant diffusion.