Research On Anode Two-phase Flow For Fluid Of Micro Direct Methanol Fuel Cell

Micro direct methanol fuel cell (Micro Direct Methanol Fuel Cell, μDMFC) have a lotof great advantages,For example, methanol sources are clean, abundant and convenient storage, the processof Chemical reaction always has the low temperature. The fuel cells can be integtated intobattery pack,and can be made into micro-batteries in order to take along. They have alonger working time than conventional batteries and less pollution. μDMFC is most likelyto replace conventional batteries to become one of the new power supply for portableelectronic devices.In this thesis, we use the Lattice Boltzmann Method(LBM), and we investigative themovement of the bubbles generated inside the battery in the electrochemical reactiontheoretically. Thus, a theoretical guidance for the optimization of cell structures as well asadjusting the reaction conditions are provided. So we can reduce the design cycle time andcost of the battery effectively. Therefore, the internal two-phase flow in micro directmethanol fuel cell research is particularly important.In this thesis, COMSOL software is applied to simulate gas-liquid two-phase flow andmass transfer in detail, and visualization experiments are used to verify the correctness ofthe simulation results. The visualization experiments also Analysis a variety of effectsunder the microscale which is different from the normal scale and large-scale conditions.The results showed that, in terms of the structure, the pore size and hydrophili of flowchannel as well as the cross-section shape have a great influence on the bubble dynamics.Secondly, the effect of imports and exports display that the structure of import and exporthave a great impact on the bubble removal. In the terms of reaction conditions, we usevisualization experiments to research the flow rate and concentration of methanol have agreat impact on the effective exclusion of carbon dioxide bubbles. And the gas remain timein the flow channel, and the detailed relationship between the bubble radius and structuralparameters as well as working conditions have been explored. The simulation method hasidentified optimized structures and the experimental conditions which have the mosteffective way of bubble excluded. The experiments results are expected.This thesis provides a theoretical basis for the optimized design and application ofmicro fuel cells effectively and can save the cost and time during the process of design.