Numerical Analysis of Gas Flows in a Microchannel Applying the Cascaded Lattice Boltzmann Method with Varying Bosanquet Parameter

In this study, a Cascaded Lattice Boltzmann Method with second-order slip boundary conditions is developed for inspecting gaseous flows in a microchannel in the slip and transition flow regimes with a wide range of Knudsen numbers. For the first time, the effect of wall confinement is deliberated on the effective mean free path of the gas molecules using a function with the nonconstant Bosanquet parameter as a substitute for the constant one. The constant-force driven and pressure-driven gas flows in a long microchannel are inquired under various conditions. The results of the velocity profile, pressure distribution, and flow rate are in good agreement with the benchmark solutions and experimental data in previous works. Further, the Knudsen minimum phenomenon is also well captured by the proposed model. The proposed Cascaded Lattice Boltzmann Method indicates a clear improvement in predicting the behavior of gaseous flows in microchannels for the previous classic and Cascaded Lattice Boltzmann Methods.