化工学报 ›› 2009, Vol. 60 ›› Issue (3): 627-633.

• 催化、动力学与反应器 • 上一篇    下一篇

微型燃烧器内甲烷预混催化燃烧的数值研究

张力;闫云飞;李丽仙;冉景煜   

  1. 重庆大学动力工程学院;重庆大学化学化工学院
  • 出版日期:2009-03-05 发布日期:2009-03-05

Numerical investigation of premixed catalytic combustion of methane in micro-combustor

ZHANG Li;YAN Yunfei;LI Lixian;RAN Jingyu   

  • Online:2009-03-05 Published:2009-03-05

摘要:

微尺度燃烧存在热量损失大、易熄火、燃烧不完全、转化效率不高等问题,因此对微型燃烧器内甲烷的燃烧采取预混催化燃烧方式来提高燃烧的稳定性和转化效率,为微型发动机碳氢燃料燃烧技术奠定基础。采用连续介质层流有限速率模型和二阶离散方法对微型燃烧器微流道内的催化燃烧、流动和传热进行了三维数值模拟。结果表明,甲烷质量流量和过量空气系数对催化转化效率有一定影响,壁面温度是影响催化转化效率的主要因素。甲烷质量流量、壁面温度与最佳过量空气系数之间具有一定的变化关系。可根据催化温度选择富燃料或富氧燃烧方式来提高微尺度催化转化效率。恒壁温边界条件下,催化燃烧主要发生在燃烧腔的下壁面。

关键词:

微型燃烧器, 甲烷, 预混, 催化燃烧

Abstract:

The characteristics of micro-combustion are easy flameout,great heat loss,incomplete combustion and low efficiency. The premixed catalytic combustion of methane can improve combustion stability and combustion efficiency. The premixed catalytic combustion characteristics of methane in micro-combustor were studied. It lays the foundation for the combustion technology of hydrocarbon-fuel in micro-engine. Numerical investigation of catalytic combustion,flow and heat transfer in micro-combustor was made by using laminar finite-rate and second-order upwind discretization model. The results showed that the mass flow rate of methane and excess air coefficient had an influence on catalytic combustion efficiency. Wall temperature was a primary factor of catalytic combustion efficiency. The optimal coefficient of excess air was related to the mass flow rate of methane and wall temperature. To improve micro catalytic combustion efficiency,an appropriate oxygen-enriched(or fuel-rich)combustion method should be selected according to wall temperature. Under the thermal boundary condition of constant wall temperature,catalytic combustion mostly happened on the downside wall of combustion-chamber.

Key words:

微型燃烧器, 甲烷, 预混, 催化燃烧