Numerical study of capillary-driven flow in square micro-channel by lattice Boltzmann method

This paper presents an investigation into capillary rise dynamics in a vertical square micro-channel based on the lattice Boltzmann method with the Shan-Chen multiphase model. Several different numerical test problems are carried out to validate the model and to provide parameter information, which is then used to simulate the wetting fluid rise in a square tube. The numerical simulation results depict fast flow and accumulation of liquid in the capillary corners. The dynamics of the liquid penetration into a square capillary is also illustrated, which reveals the occurrence of oscillations at the initial time before the liquid reaches a stable regime. Furthermore, the streamlines inside the square capillary as well as the density profiles are obtained by the numerical simulations. The results show the existence of recirculation zones in the cross section and in the inlet region of the micro-channel. The dynamic contact angle was clearly observed via the numerical simulations. Finally, the dynamics of capillary rise were also studied for the micro-channel in which a thin vertical plate was integrated.