Numerical investigation on motion characteristic of a bubble rising along overheated surfaces with different curvatures

Abstract

In present work, a two-phase thermal LBM model for simulating liquid-gas phase transition in body-fitted coordinate system is proposed. Subsequently, model validation is performed by simulating bubble growth in the superheated liquid without consideration of gravity. After that, the hydrodynamic and thermodynamic behaviors of a bubble during its rising and sliding process along overheated surfaces are analyzed and compared in three cases with different surface axial ratios. The results indicate that bubble experiences the largest deformation and growth in the case with surface axial ratio a/b=1.5 . As for bubble average velocity, its horizontal component increases with surface axial ratio, yet opposite for vertical one. The influences of bubble deformation and growth on temperature field become more significant in the case with a larger axial ratio. Besides, the existence of bubble causes an extremely high temperature gradient on the surface during its sliding stage; such effect is weakened gradually as the bubble departs from surface and moves to the far field.