| Dynamics of multiphase systems in micro-fluidic devices is a topic of great interest in many industrial applications such as chemical synthesis, DNA analysis, enhanced micromixing, and power generation. Due to the small transverse dimensions, microchannels provide a great surface to volume ratio, offering an enhanced heat and transfer efficiency. In addition, they provide a great alternative for many chemical reactions by minimizing the amount of reactants needed. Different from large scale channels, bubbles can create significant problems in micro-fluidic devices by altering or blocking the flow. On the other hand, controllable addition of bubbles is desired to improve mixing and heat transfer in microsystems. Therefore it is important to understand clearly the dynamic behavior of multiphase systems, from the point of formation to transport along the microchannel. Bubble formation dynamics is governed by the set-up geometry and ratio between interfacial and viscous forces in the system. Multiphase flow transport along microchannel is determined by wall surface wettability, initial fluid conditions, and velocities. A stable Lattice Boltzmann Method (LBM) based on the Cahn-Hilliard diffuse interface approach is used for the simulation of bubble formation and motion along the microchannel. Initial validation of the model is presented for the dynamics of a single bubble rising in unconfined and confined domains. |
