Advances in multiscale numerical simulation of gas–liquid two-phase flows in liquid metals

The gas–liquid two-phase flow of liquid metals has important applications in extreme industrial scenarios such as nuclear reactor cooling, aerospace thermal control, and additive manufacturing. However, its complex gas–liquid interface dynamics, coupling of phase change heat transfer, and interactions among multiple physical fields pose challenges to traditional numerical methods. This review comprehensively surveys recent advances of multiscale numerical simulations in this field, covering macroscopic, mesoscopic, and microscopic scale methods. At the macroscopic scale, the improvements and optimizations of the finite volume method, finite difference method, and custom numerical algorithms in phase interface tracking, porous medium coupling, and complex boundary treatment are analyzed with emphasis. At the mesoscopic scale, the mesoscopic modeling methods for the coupling of gas–liquid phase change heat transfer in porous media and microchannels are discussed. At the microscopic scale, the latest achievements of interface dynamics and molecular scale simulations are summarized. The limitations of current research are further analyzed, including issues such as insufficient accuracy of porous medium modeling, large errors in phase change heat transfer models, and limited ability to analyze interface dynamics. This review proposes future research directions: developing high-precision interface and phase-change models, achieving multiscale-method coupling, and optimizing numerical algorithms through machine-learning integration. It aims to offer theoretical references and technical support for the multiscale simulation of gas–liquid two-phase flow in liquid metals.