Simulations on Ostwald Ripening by Using Lattice Boltzmann Methods*

Lattice Boltzmann methods have solid basis of particle kinetics, and it can be extended to simulations for multiphase flows by simply adding inter-particle forces. It is proven that it shares common fundamentals with thermodynamic models, saying phase field model. Growth of bubbles is simulated by Shan-Chen multiphase lattice Boltzmann methods (SC-LBM). The tests for single and dual bubble growth show SC-LBM simulation agrees with Rayleigh-Plesset predictions, which is applied widely for cavitating phenomena. Further tests for a cluster of bubbles show that such processes fulfill reaction-limited phase separation (coarsening), one of the important regimes of Ostwald ripening. During the processes, a thermal equilibrium is reached, while the interfacial energy keeps decreasing. The phenomenon of larger bubble eating smaller bubble can be well captured. The results also show that the  R ̅∼t^(1/2) and N∼t^(-1) scalings are well satisfied, where R ̅, N and t are the averaged bubble size, bubble number and time, respectively. We believe SC-LBM has great potential to be applied in both mechanical and chemical circumstances.