LBM simulates the effect of sole nucleate site geometry on pool boiling

Abstract

A two-particle distribution functions lattice Boltzmann method is selected to simulate periodic bubble nucleation, growth and departure from four different boiling nucleate cavity structured surfaces: square, circular, trapezoidal, and inverted trapezoidal. The effects of different structured nucleate site on bubble growth and departure are investigated in this paper. Fluid hydrodynamic and thermodynamic are characterized by the density distribution function and the temperature distribution function respectively. Pseudo-potential model and Peng-Robinson equations of state are selected in our simulations. Constant temperature boundary condition is applied to the bottom solid. It is found that at the four different structure cavity surfaces, at the given superheat temperature 0.96Tc, all the cavities are activated as boiling nucleate sites, but the onset boiling time on circular and trapezoidal cavity structure surfaces are shorter than on the other two surfaces. The temperature distribution pictures and the heat flux variation pictures for the four different cavity surfaces are given to analyze the heat transfer performance on different surfaces. The temperature distributions have obvious different on different cavity geometry surfaces in the bubble nucleation process. The heat flux distribution pictures show that the main heat transfer mechanism in nuclear boiling process is the microlayer evaporation.