具有梯度孔隙率的多孔介质封闭方腔内的自然对流

Natural Convection in a Closed Square Cavity of Porous Media with Gradient Porosity

为研究梯度孔隙分布多孔介质内自然对流流动和传热问题,建立了三种不同孔隙率分布的多孔介质模型,采用有限元方法进行了模拟计算。基于场协同理论分析了具有梯度孔隙率的多孔介质方腔内速度场与温度梯度的协同关系,探讨了不同方向孔隙率梯度分布对多孔介质腔体内温度场和速度场的影响。研究结果表明,梯度孔隙率的多孔结构低孔隙率区域通过导热强化传热,高孔隙率区域随着Ra数的增加,对流换热逐渐增强,平均Nu数增大很快,具有梯度孔隙率的多孔介质封闭方腔内的自然对流得到强化。

In order to study the natural convection flow and heat transfer in porous media with gradient pore distribution, three porous media models with different pore distribution were established and simulated by finite element method. Based on the field synergy theory, the synergistic relationship between the velocity field and the temperature gradient in the square cavity of porous media with gradient porosity is analyzed, and the influence of the gradient distribution of porosity in different directions on the temperature field and the velocity field in the cavity of porous media is discussed. The results show that heat transfer is enhanced by thermal conduction in the low porosity region of porous structure with gradient porosity. With the increase of Ra number, convective heat transfer is gradually enhanced in the high porosity region, and the average Nu number increases rapidly. Natural convection in the enclosed square cavity of porous medium with gradient porosity is enhanced.