中文摘要：

通过对竖直放置直接甲醇燃料电池水平流道内扩散层壁面上CO2气泡的受力分析，建立描述气泡生长动力学方程，获得CO2气泡生长速率和气泡脱离直径的计算方法。计算结果表明：CO2气泡生长和脱离主要受浮力、曳力、剪切升力和表面张力的控制；气泡生长速率随电流密度和接触环直径的增大而增大；甲醇溶液流速增加，气泡脱离直径变小，且流速对气泡脱离直径的影响随接触环直径减小而变大；电池放电电流密度的变化对气泡脱离直径几乎没有影响；温度和甲醇浓度增加，均使气泡脱离直径略有减小；扩散层表面润湿性越好，气泡的脱离直径越小。

英文摘要：

Characteristics of CO2 bubble growth and departure from a vertical gas diffusion layer surface was studied in the horizontal flow channel of a Direct methanol fuel cell （DMFC）. Forces acting on a CO2 bubble were analyzed. Dynamical equations were established, by which bubble growth rate and departure diameter can be calculated. The results show that CO2 bubble growth and departure mainly controlled by buoyancy, drag force, shear lift force and surface tension force. Both a higher current density and a bigger diameter of contact ring can accelerate the growth of C02 bubble. The bubble departure diameter decreased with the increasing of methanol solution flow rate, but the diameter of contact ring grew bigger, the influence of flow rate on bubble departure diameter grew weaker. The variance of current density has negligible impact on bubble departure diameter. With the increasing of temperature and methanol concentration, the bubble departure diameter slightly reduced. Improving the surface wettability of gas diffusion layer, the bubble departure diameter also becomes smaller.