| The fast development of automotive industry has improved the life level of people, but it has also caused the proliferation of the demand for petroleum and the environment deterioration.In order to walking out of this morass, we have two approaches: (1) modifying the traditional automotive using advanced combustion technique, fuel technique and post-disposal technique, and setting more strict regulation of the automotive pollutants emission; (2) developing new energy automotive. For the long run, it is an effective way to solve these problems to develop new energy automotive, especially fuel cell automotive based on hydrogen energy, which has causen increasing attention of people.Proton exchange membrane (PEM) fuel cell is suitable for fuel cell automotive because of its characteristics. Against the deficiencies in the present studies on PEM fuel cells, the PEM fuel cells with conventional flow field and interdigitated flow field has been simulated systemicly and the water management experimental researche on them has been performed with a combined researching way of numerical simulation and experiment in this study. An authenticity-improved, three-dimensional, non-isothermal, gas-liquid two-phase flow and transport mathematic model has been developed to simulate the PEM fuel cells with conventional flow field and interdigitated flow field systemicly. It is a success to inspect the flow regime of the gas-liquid two-phase flow in the PEM fuel cell using high-sensitivity double parallel conductance probes. A PEM fuel cell and internal combustion engine combined driving system has been developed and calculated.A three-dimensional, non-isothermal, gas-liquid two-phase flow and transport mathematic model has been developed. The calculation domain of the model includes the cathode/ anode flow channels, gas diffusion layers, catalyst layers and PEM of the PEM fuel cell. The developed model was solved in a computational fluid dynamics (CFD) software after it was coupled into the software through user-defined function (UDF). The calculation results for a PEM fuel cell with conventional flow field for the base case shows a good agreement with experimental data, which shows the developed model and its solving technique can be utilized to simulate the coupled three-dimensional, two-phase flow, heat and mass transfer, and electrochemical characteristic in the PEM fuel cells with conventional flow field and interdigitated flow field under different cases. The authenticity of the simulation has been improved because the three-dimensional, two-phase flow and non-isothermal characteristics in the cathode/ anode flow channels, gas diffusion layers, catalyst layers and PEM of the PEM fuel cells have been taken into account in the model at the same time.The flow field type affects the mass transfer mechanism, electrochemical characteristic, limit current density, and performance of the PEM fuel cell greatly. The calculation for the whole calculating domain of the PEM fuel cells with conventional flow field and interdigitated flow field has been performed. The three-dimensional, two-phase flow and transfer phenomena, and fuel cell performance and its influential factors have been simulated. The simulations are presented with an emphasis on the physical insight and fundamental understanding afforded by the detailed distributions of velocity vector in the flow channels and gas diffusion layers, temperature in the fuel cell, pressure in the flow channels, oxygen concentration in the cathode flow channel and gas diffusion layer, hydrogen concentration in the anode flow channel and gas diffusion layer, water vapor and liquid water concentrations in the flow channels and gas diffusion layers, net water flux per proton flux and water content in the PEM , overpotential and local current density for the PEM fuel cells with conventional flow field and interdigitated flow field. Cell performances of the PEM fuel cells with conventional flow field and interdigitated flow field with different cathode oxidants, channel inlet gas velocities, channel outlet pressures, PEM thicknesses, and channel rib widths are also presented and discussed. The influential degrees of these factors have been compared, and the order is the oxidant, flow field type, channel outlet pressure, channel inlet gas velocity, channel rib width and PEM thickness. Replacing the conventional flow field with interdigitated flow field, replacing the oxidant, air, with oxygen, increasing the inlet gas velocity and channel outlet pressure, and decreasing the widths of the PEM and channel rib can improve the performance of the PEM fuel cells. Based on the analysis, we know that the performance of the PEM fuel cell with interdigitated flow field is better than that of the PEM fuel cell with conventional flow field. The simulation results show that the developed mathematic model can provide detailed parameter distributions of the three-dimensional, two-phase flow and transfer, and electrochemical characteristic in the PEM fuel cells, and optimize the design and operation parameters of the PEM fuel cells. It is the first time to simulate a PEM fuel cell with interdigitated flow field in detail with a three-dimensional, non-isothermal, two-phase flow and transport mathematic model.Gas- liquid two-phase flow is a common phenomenon in the operation of the low-temperature PEM fuel cell. However, the research about it is few, and the commonly used research approach is visualization, which can not research the cell unit that dose not locate by the cathode end-plate. A simulated cathode flow channel experiment system was set up based on the gas flow flux and water flow flux in the PEM fuel cell. With the assistant of the visualization system, high-sensitivity double parallel conductance probes flow regime inspecting technique was adopted successfully in the experiment system to inspect the flow regime of the gas-liquid two-phase flow in the PEM fuel cell. The research results show that the double parallel conductance probes inspecting system and the flow regime image system for the gas-liquid two-phase flow in the PEM fuel cell simulated channel both can judge the slug flow and annular flow in it, and the double parallel conductance probes flow regime inspecting system can divide the annular flow into three subtypes. The probe inspecting system can research the cell unit that dose not locate by the cathode end-plate. The main probes inspecting system and the assistant image system validate reciprocally, which enhances the experimental veracity. The typical flow regimes of the PEM fuel cell simulated channel include slug flow, annular flow with big water film wave, annular flow with small water film wave and annular flow without water film wave. With the increase of the liquid superficial velocity, the frequencies of liquid slug and wave of liquid film increase. The flow regime map in the flow channel of the PEM fuel cell was developed with the abscissa axis of the gas superficial velocity and the vertical axis of the liquid superficial velocity. The flow regime of the gas-liquid two-phase flow in a PEM fuel cell in different operating conditions can be forecasted with this map. With the PEM fuel cell operating condition in this dissertation, the flow regimes of gas-liquid two-phase flow for different cases are all annular flow with small water film wave, and the liquid film waves more with bigger current density. With the location closer to the channel outlet, the liquid film waves more for the same current density.Based on the characteristics of PEM fuel cell, a PEM fuel cell and internal combustion engine combined driving system was developed. The PEM fuel cell and inter-combustion engine combined system was adopted to drive a bus; cold/ hot air was provided by a gas air-conditioner in the system. The mass balance and heat balance calculation for the system shows the efficiency of the whole system reaches more than 50%, which is higher than that of internal-combustion engine. Further more, the system can reduces the pollutants emmision. As a result, the fuel is utilized efficiently and cleanly.
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