Three-dimensional lattice Boltzmann model for gaseous flow in rectangular microducts and microscale porous media

摘要

Microscale fluid dynamics has received intensive interest due to the rapid advances in microelectromechanical systems. In this work, the lattice Boltzmann method is applied to simulate isothermal gaseous slip flow in three-dimensional (3D) rectangular microducts and microscale porous structures. The flow characteristics in 3D microducts—including velocity profile, nonlinear pressure distribution, friction factor, and mass flow rate—are compared with analytical solutions, and the agreement is good. The flow-rate results show that due to the slip-velocity emergence at the walls, the lateral wall influence on the flow rate in 3D rectangular microducts is decreased. The predicted transport characteristics in 3D microscale porous media show that the rarefaction influence increases the gas permeability. The Klinkenberg effect is confirmed and the predicted gas permeability is qualitatively consistent with the experimental results. Furthermore, the nonlinear behavior of the porous flow at relatively higher Reynolds number is also observed. This study demonstrates that the lattice Boltzmann method can be employed to efficiently predict transport characteristics in microducts and microscale porous media.