A single micro proton exchange membrane fuel cell （PEMFC） has been produced using Micro-electromechanical systems （MEMS） technology with the active area of 2.5 cm 2 and channel depth of about 500 μ m.A theoretica...A single micro proton exchange membrane fuel cell （PEMFC） has been produced using Micro-electromechanical systems （MEMS） technology with the active area of 2.5 cm 2 and channel depth of about 500 μ m.A theoretical analysis is performed in this study for a novel MEMS-based design of a micro PEMFC.The model consists of the conservation equations of mass,momentum,species and electric current in a fully integrated finite-volume solver using the CFD-ACE＋ commercial code.The polarization curves of simulation are well correlated with experimental data.Three-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature,current density and water distributions in two different fuel flow rates （15 cm 3 /min and 40 cm 3 /min）.Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4 V operating voltage.Model predictions are well within those known for experimental mechanism phenomena.展开更多
The motion of micro-particles with different mass flow rate in the planer turbulent jet flow has been simulated,using LES method to obtain the flow vorticity evolution and Lagrangian method to track micro-particles.Th...The motion of micro-particles with different mass flow rate in the planer turbulent jet flow has been simulated,using LES method to obtain the flow vorticity evolution and Lagrangian method to track micro-particles.The results showed that when the flow rate is small,the particles more likely to present in the vortex periphery,the distribution pattern is similar to the flow pattern.When the flow rate is high,some particles will escape from the motion region to the original static region,so that in the jet region,particles are relatively evenly distributed.When the flow field is full developed,the particles average concentration in the y direction affected by the mass flow rate relative slightly,the normalized mean particles concentrations at different flow rate were similar to Gaussian shape.展开更多
基金National Science Council for financially supporting this research under Contract No. NSC98-2221-E-009-162
文摘A single micro proton exchange membrane fuel cell （PEMFC） has been produced using Micro-electromechanical systems （MEMS） technology with the active area of 2.5 cm 2 and channel depth of about 500 μ m.A theoretical analysis is performed in this study for a novel MEMS-based design of a micro PEMFC.The model consists of the conservation equations of mass,momentum,species and electric current in a fully integrated finite-volume solver using the CFD-ACE＋ commercial code.The polarization curves of simulation are well correlated with experimental data.Three-dimensional simulations are carried out to treat prediction and analysis of micro PEMFC temperature,current density and water distributions in two different fuel flow rates （15 cm 3 /min and 40 cm 3 /min）.Simulation results show that temperature distribution within the micro PEMFC is affected by water distribution in the membrane and indicate that low and uniform temperature distribution in the membrane at low fuel flow rates leads to increased membrane water distribution and obtains superior micro PEMFC current density distribution under 0.4 V operating voltage.Model predictions are well within those known for experimental mechanism phenomena.
基金supported by National Natural Science Foundation of China (Grant No. 50976107 and 51206149)National Key Technology R&D Program of China (Grant No. 2009BAF39B01)Zhejiang Science Technology Project (Grant No. 2011C11073)
文摘The motion of micro-particles with different mass flow rate in the planer turbulent jet flow has been simulated,using LES method to obtain the flow vorticity evolution and Lagrangian method to track micro-particles.The results showed that when the flow rate is small,the particles more likely to present in the vortex periphery,the distribution pattern is similar to the flow pattern.When the flow rate is high,some particles will escape from the motion region to the original static region,so that in the jet region,particles are relatively evenly distributed.When the flow field is full developed,the particles average concentration in the y direction affected by the mass flow rate relative slightly,the normalized mean particles concentrations at different flow rate were similar to Gaussian shape.
