多孔介质的孔隙特性对气体扩散过程影响的直接数值模拟

Numerical simulation for influence of pore characteristics on gas diffusion in porous media

引言多孔介质内的扩散过程广泛存在于化工、能源、环境和生物等领域,例如石油天然气开采、污水处理、填充床化学反应、催化剂和生物组织内的质量传递等,使得多孔介质内传质现象的研究尤为重要[1-2]。多孔介质由于结构和形状各异,难以有准确、有效且简单的描述方法。

Micro-structure of porous medium that approximates natural porous medium is generated stochastically by numerical method.Numerical simulation of gas diffusion in porous media is implemented with LTRT lattice Boltzmann method to investigate the effects of pore characteristics on diffusion process.It is demonstrated that diffusion processes are quite different in different porous micro-structures with the same porosity.The results also show that the dimension of the width of channels influences the diffusion.The diffusion rates increase as the channel width increases.The effect resulted from the variation of channel width and porosity in the diffusion process is far less than that for different pore structures.The influence caused by the variation of radii of filleted corners is little.These explorations provide theoretical basis and statistical support for the generation of porous media and the design and optimization of the pore characteristics of micro-reactor.