环形微细腔内甲烷催化转化效率的数值模拟

Numerical Simulation of Catalytic Conversion Efficiency of CH_4 in Annular Micro-chamber

甲烷在微燃烧器内存在燃烧效率不高、燃烧不稳定等问题。为了研究微尺度下甲烷持续稳定燃烧的性能，采用催化燃烧方式对环形微细腔内甲烷与空气混合物在铂催化表面上的催化燃烧进行了数值模拟，研究了甲烷当量比、壁面温度对微通道内甲烷与空气混合物催化燃烧的甲烷转化效率的影响。结果表明，甲烷当量比、壁面温度对甲烷转化率有重要影响，通过催化可以促进甲烷在环形微细腔内的稳定燃烧。为了获得较高的甲烷转化效率，微燃烧器入口的甲烷当量比在0．8～1．0范围内较为合理，温度是影响环形微细腔内甲烷催化燃烧的主要因素，尤其在甲烷当量比较低时，温度的提高对甲烷的催化转化有更好的促进作用。甲烷的质量流量为6．5g／h时，甲烷催化转化效率可达77％。

Generally, combustion of methane in micro chamber has some problems such as low efficiency and nonsteady. In it has been proposed that the steady combustion in micro-scale could be achieved with catalyst method. The influence of molar ratio of CH4/air and catalytic temperature for combustion in annular micro-chamber have been studied when Pt was used as catalyst. The results suggest that these factors have important influences on the combustion of CH4/air mixture in annular micro-chamber, and the steady of combustion can be improved via catalysis approach. The ideal molar ratio of methane/air for combustion is obtained as 0.8 - 1.0. Catalytic temperature playsa key role on the combustion of methane in micro chamber. The higher temperature can accelerate catalytic combustion of CH4/air mixture as the molar ratio of CH4 is small. When flow rate of methane is 6.5 g/h, the maximal conversion efficiency of methane is 77%.