Investigation of vapor condensation on a flat plate and horizontal cryogenic tube using lattice Boltzmann method

摘要

In this paper simulation of vapor condensation, liquid film formation, and dew drop sprinkling from cryogenic horizontal tube base on two-dimensional lattice Boltzmann method is presented. Lee's multiphase model is used which is applicable to high density and viscosity ratios. The passive scalar thermal lattice Boltzmann framework and proper source term due to phase change are combined with the multiphase model to simulate the film condensation. Lee's model is based on convective Cahn-Hilliard equation and the divergence-free condition of the velocity field. However, as the phase change occurs at the interface, the divergence-free condition is no longer satisfied. The simple passive scalar approach is employed for the evolution of the temperature field in the computational domain and the flow field is affected by temperature under the hypothesis of Boussinesq. The D2Q9 lattice structure is used for the case of density ratio of 25), and the effects of gravitational superheating, contact angle and the temperature of sub-cooled tube on vapor condensation are illustrated. Finally flow fields and three-phase contact line movement of film condensation are analyzed.