Two-phase flow in anode flow field of a small direct methanol fuel cell in different gravities

被引:0
作者
Hang Guo
Feng Wu
Fang Ye
JianFu Zhao
ShiXin Wan
CuiPing Lü
ChongFang Ma
机构
[1] Beijing University of Technology,Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education of China, College of Environmental and Energy Engineering
[2] Beijing University of Technology,Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality
[3] Chinese Academy of Sciences,Institute of Mechanics
来源
Science in China Series E: Technological Sciences | 2009年 / 52卷
关键词
direct methanol fuel cells; microgravity; two-phase flow; visualization; bubble behavior;
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学科分类号
摘要
An in-situ visualization of two-phase flow inside anode flow bed of a small liquid fed direct methanol fuel cells in normal and reduced gravity has been conducted in a drop tower. The anode flow bed consists of 11 parallel straight channels. The length, width and depth of single channel, which had rectangular cross section, are 48.0, 2.5 and 2.0 mm, respectively. The rib width was 2.0 mm. The experimental results indicated that when the fuel cell orientation is vertical, two-phase flow pattern in anode channels can evolve from bubbly flow in normal gravity into slug flow in microgravity. The size of bubbles in the reduced gravity is also bigger. In microgravity, the bubbles rising speed in vertical channels is obviously slower than that in normal gravity. When the fuel cell orientation is horizontal, the slug flow in the reduced gravity has almost the same characteristic with that in normal gravity. It implies that the effect of gravity on two-phase flow is small and the bubbles removal is governed by viscous drag. When the gas slugs or gas columns occupy channels, the performance of liquid fed direct methanol fuel cells is failing rapidly. It infers that in long-term microgravity, flow bed and operating condition should be optimized to avoid concentration polarization of fuel cells.
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