In this study, gaseous flow through a micro/nano-channel is investigated via a novel two relaxation time lattice Boltzmann method (TRT-LBM). In this method, the slip velocity at the fluid-solid interface is realized by defining the free relaxation parameter. Furthermore, in order to capture the non-linear phenomena associated with the Knudsen layer, the wall function correction is employed. To this respect, different available wall functions are implemented. The objective of the study is to provide a comparative study on the accuracy, range of applicability and computational efficiency of these wall functions in a wide range of Knudsen numbers. The results of the present study are compared against direct simulation Mont Carlo (DSMC) and information preservation (IP) data. It is found that only a few of the implemented wall functions are capable of predicting the flow behavior with reasonable accuracy, particularly when the Knudsen number lies in the transition flow regime.

Keywords