Simulation Of Interfacial Convection Via Lattice Boltzmann Method

Interfacial transport phenomena play an important role in mass transfer process. The density gradient and surface tension gradient caused by the existence of concentration gradient at the interface, may lead to the loss of stableness of the interface and then the interfacial convections (also known as interfacial turbulence). This kind of interface convections could enhance the mass transfer and have drawn much attention of research.The most up-to-date experimental studies can give some detailed observations on this phenomenon, but it is difficult to reach some quantitative results. In this work, the Lattice Boltzmann Method (LBM) is introduced and implemented to simulation quantitatively the interfacial convection phenomena.The Lattice Boltzmann Method is developed from the Lattice Gas Automata (LGA). It is based on the molecule dynamics theory and statistical mechanics. This method discrete the space, time and velocity, and it can be used to simulate the mesoscopic phenomenon of fluid flow with the simple particles collision principles. Comparing to the traditional CFD methods, LBM has advantages in simulating fluid flow in mesoscopic scale and parallel calculation.In this dissertation, the theory of the Lattice Boltzmann Method is introduced. Some exercises are provided to prove that this method is reliable with its mature model. Then interfacial convection processes are simulated with this method, and the results of concentration distributions are well agreed with the experimental observation. Additionally, different cases with variety of values of Rayleigh number (Ra) are simulated in order to find out the critical value for Ra, the result shows that the calculated critical Ra is agree with the experimental results.The study in this work demonstrated that the Lattice Boltzmann Method, as a new CFD method, provides a promising alternative to the approach to the quantitative simulation for the interfacial convection phenomena.