A GPU-accelerated Helmholtz-EOS lattice Boltzmann method with modified MLS curved boundary for pool boiling on grooved surfaces

A GPU-accelerated pseudopotential lattice Boltzmann method (LBM) integrating a Helmholtz-energy equation of state (HEOS), an improved Mei-Luo-Shyy (MLS) boundary condition, and a fluid-solid conjugate boundary condition (CBC) is developed to investigate pool boiling on complex grooved surfaces. The HEOS improves thermodynamic consistency in liquid-vapor phase-change modeling compared with conventional cubic equations of state, while the modified MLS-CBC treatment accurately resolves fluid-solid conjugate heat transfer over complex geometries. Implemented via GPU parallel computing, the unified framework enables efficient simulation of complete boiling curves from natural convection to film boiling. Systematic comparison of smooth, triangular-grooved, and circular-grooved surfaces reveals that the circular groove enhances critical heat flux (CHF) by 107% over a smooth surface, yet its geometry promotes premature vapor film coverage at high superheat. In contrast, the triangular groove, despite a marginally lower CHF (6% lower than the circular case), delays the onset of film boiling due to geometric continuity. The enhanced nucleation and bubble dynamics on grooved surfaces induce more vigorous three-phase contact line motion and stronger thermal fluctuations than those on smooth surfaces.