Lattice Boltzmann simulation of falling film flow under low Reynolds number

Abstract

In this paper, a new two-dimensional simulation model was developed for the falling film flow under low Reynolds number (below 20). The phase-field multiphase lattice Boltzmann model was developed to simulate the flow pattern of the two-phase falling film with high density ratio. The approaches to treating the liquid-gas interface with high density ratio (up to 775), surface tension, gravity, inlet and outlet open boundary conditions as well as solid-liquid interface considering contact angle were developed firstly, and then implemented in the model. The dynamic characteristics of the film flow, including the development of the liquid-gas interface and the film thickness, were simulated under the Reynolds numbers between 1.0 and 20. The results show that the film is fully laminar under low Reynolds numbers. The falling film flow model developed in this study lays the foundation for the study of heat and mass transfer in the falling film based liquid desiccant dehumidifier.