Curved boundary in multiphase flow simulations remains a formidable challenge for the lattice Boltzmann method. This is fraught with problems such as mass leakage and spurious currents. To address these issues, the present work proposes two improved curved boundary schemes by introducing non-ideal force into two extrapolation-based schemes (i.e., Mei-Luo-Shyy (MLS) scheme and Guo-Zheng-Shi (GZS) scheme), followed by mass-conservation correction. Moreover, an additional term is introduced. The accuracy and mass conservation of the two proposed boundary schemes are thoroughly validated through two numerical tests of droplet resting on a circular cylinder and boiling on a circular cylinder. The present improved schemes strictly not only ensure exact (i.e., 100%) mass conservation, but also have improved in terms of the spurious current. Furthermore, the present improved schemes are suitable for simulating boiling on curved surfaces.

curved boundary, lattice Boltzmann method, multiphase simulation, pseudopotential model