CO_2气泡脱离扩散层孔口过程的数值模拟  

Simulation of Carbon-Dioxide Bubble Detachment Process from Diffusion Layer Orifice

作　　者：张怀生[1] 王良华[1] 章渊昶[1] 姚克俭[1] 

机构地区：[1]浙江工业大学化学工程与材料学院绿色化学合成技术国家重点实验室培育基地,浙江杭州310032

出　　处：《高校化学工程学报》2010年第1期35-40,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：浙江省自然科学基金项目(Y406163)

摘　　要：在直接甲醇燃料电池(DMFC)中,阳极催化层表面反应生成的CO2气体通过扩散层,及时排出阳极通道,对提高DMFC电流密度具有重要意义,因此研究气泡脱离孔口的过程很有益。今采用Fluent6.2.16对CO2气泡脱离扩散层孔口过程、两孔时气泡形成及聚并过程进行了数值模拟,考察了阳极通道内液体流速、扩散层孔道直径等因素对气泡脱离的影响。结果表明,阳极通道内液体流速越大,气泡脱离扩散层孔口所需的时间越短;扩散层孔道直径越大,气泡脱离扩散层孔口所需的时间越长,且生成的气泡越大;由于从相邻两扩散层孔道出来的气泡的阻挡和挤压作用,使得两气泡周围的压力分布与单气泡不同,气泡脱离过程与从单个扩散层孔口的脱离过程有所不同,脱离时间更早。In the direct methanol fuel cell （DMFC）, CO2 gas is generated on the surface of the anode catalyst layer, it should pass through the orifices on the diffusion layer and flow into the anode channel, via which the CO2 is exhausted from the DMFC. Exhaust promptly the CO2 from the DMFC is important for the improvement of the current density of the DMFC, therefore knowing the CO2 detachment process from the diffusion layer orifice is helpful. Fluent 6.2.16 was used tO simulate the detachment process of the CO2 bubble from the orifice of the diffusion layer, and the processes of bubble formation and coalescence when bubbles flow out from adjacent diffusion layer orifices were simulated too. The effects of the iiquid velocity in anode channel and the size of the diffusion layer orifice on the bubble detachment were investigated, and the results show that the faster the liquid velocity in the anode channel, the shorter the time for bubble detaching from the diffusion layer orifice. The larger the size of diffusion layer orifice, the longer the time for bubble detaching from it, and the larger the bubble forming in the anode channel. Due to the obstruction and compression between the bubbles formed from two adjacent diffusion layer orifices, in the anode channel, the pressure distribution near two adjacent bubbles is different from that around the single bubble formed when only one diffusion layer orifice exists; the bubble detachment process for bubbles formed from two adjacent orifices is different from that for one bubble formed from single diffusion layer orifice, and the bubbles detach earlier than the bubble formed from single diffusion layer orifice.

关 键 词：直接甲醇燃料电池 阳极通道 扩散层 气泡 数值模拟 

分 类 号：TM911.4[电气工程—电力电子与电力传动]