格子玻尔兹曼方法模拟PEM燃料电池阴极的热质耦合反应传递
Simulation of Coupled Heat and Mass Transport With Reaction in PEM Fuel Cell Cathode using Lattice Boltzmann Method
摘要：
采用多重弛豫格子玻尔兹曼方法模拟了质子交换膜（PEM）燃料电池阴极中的流体、热量和组分输运以及氧还原过程。考虑了由于氧还原产生的热量及其对运输和反应的影响。模拟不同的电池工作电压，温度和流速与多孔介质的性质，即渗透率，孔隙率，和有效的多孔介质扩散系数的各种值，进行研究的电极中的传输和操作特性。可以看出，可实现的最大输出功率密度受到质量传输速率的限制。通过提高工作温度可以获得电流密度的小幅增加。然而，这会导致发热速率的增加。气体扩散层的渗透率和孔隙率在目前模拟的值范围内对性能没有显着影响。更高的渗透性，反过来，导致在多孔层中的热梯度的增强。随着流速的增加，观察到可获得的最大电流密度显著增加。与高流速相关的较高对流促进了催化剂层处物质和热量的更好传输，导致较大的电流密度，热点形成的可能性较小。物种扩散系数的增加也导致功率输出大幅增加。此外，在多孔介质中的高扩散速率下也提高了燃料利用率。该研究分析和显示的各种操作和材料参数的影响，影响性能的PEM燃料电池，特别注意提高可达到的最大功率密度。
英文摘要：
Fluid, heat and species transport and oxygen reduction in the cathode of a PEM fuel cell are simulated using multi relaxation lattice Boltzmann method. Heat generation due to oxygen reduction and its effects on transport and reaction are considered. Simulations for various cell operating voltages, temperatures and flow rates with various values of porous media properties, namely, permeability, porosity, and effective porous media diffusion coefficient, are performed to study transport and operating characteristics in the electrode. It is seen that maximum output power density achievable is limited by the mass transport rate. A small increase in current density is obtained by increasing the operating temperature. However, this results in an increase in the rate of heat generation. Permeability and porosity of the gas diffusion layer do not show a significant impact on the performance in the range of values presently simulated. Higher permeability, in turn, resulted in enhancement of thermal gradients in the porous layer. A significant increase in the maximum current density obtainable is observed with increase in flow rates. The higher convection associated with high flow rate facilitates better transport of species and heat at the catalyst layer resulting in larger current density with a lesser chance of hotspot formation. Increased species diffusion coefficient also resulted in increasing the power output substantially. In addition, the fuel utilization is also improved at high diffusion rates in the porous media. The study analyses and shows the impact of various operating and material parameters affecting the performance of a PEM fuel cell with special attention on enhancing the maximum power density attainable.
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