Improved lattice Boltzmann model for realistic multicomponent gas–liquid two-phase flow and its application to slug flow in T-shaped microchannels

Microscale bubble systems have enormous engineering application value. However, due to the inherent complexity of microscale multiphase flow and the size limitation of microchannels, there are limitations in the current studies of microscale bubble flow behavior based on theoretical analysis and experimental test methods. Therefore, a pseudopotential lattice Boltzmann numerical computational model suitable for simulating real microchannel bubble flow was developed in this study, and the accuracy and applicability of the model were verified. On this basis, the bubble evolution process and the effects of the gas–liquid two-phase flow rate on the evolution, length, and local flow characteristics of bubbles were investigated in a T-shaped microchannel. The liquid flow rate has a decisive influence on bubble evolution, while the gas flow rate has a small influence. The bubble length has an inverse relationship with the liquid flow rate. The gas-phase flow inside the bubble is more stable with increasing two-phase flow velocity. In the head, middle, and tail sections of the bubble, the turbulence of the flow field is higher near the centerline along the flow direction in the head, near the channel wall in the middle, and near the channel wall in the tail than in other locations of the same section. Due to the stronger local turbulence, the heat and mass transfer occurring at these three locations is more intense.