中文摘要：

对均匀空气流中微尺度甲烷扩散燃烧进行了数值模拟，重点考察微喷管内的流动和传热传质对微尺度燃烧特性的影响．结果表明，在低流速下，内径为0．3mm的微喷管内进气速度为1．0m／s时燃料与空气的混合已经发生，混合气被管外的热量预热，同时火焰的热损失增加．在喷管直径一定时，减小燃料喷出速度，传热传质现象对微尺度甲烷扩散火焰特性的影响增强；当进气速度为0．5m／s时，甲烷在微喷管内开始燃烧，放出热量．在进行微尺度解析计算时，必须包含一定的喷管区域．

英文摘要：

The methane micro diffusion flames in micro nozzle in air are investigated numerically, with the focus on the influence of heat and mass transfer in the nozzle on the characteristics of the flames. The results show that at low flow velocity, the mixing process of fuel and air takes place in the nozzle whose inner diameter is 0.3 mm and where the fuel velocity is 1.0 m/s, the mixture is preheated by the flame, and the heat loss of the flame increases. In a nozzle with the same inner diameter, when the fuel inlet velocity decreases, the effect of heat and mass transfer in the nozzle enhances accordingly. When inlet velocity is 0.5 m/s, the combustion phenomenon occurs in the nozzle, and heat is released. Therefore, it is necessary to consider and include the nozzle as the calculated zone when numerically computing the micro flames because of heat and mass transfer in the micro nozzle.