微型开缝钝体燃烧器燃烧特性数值分析

Numerical Analysis on Combustion Characteristics in Micro-Combustor with a Slotted Bluff-Body

本文将开缝钝体稳燃技术应用于微型燃烧器中,采用详细化学反应机理模拟了不同速度下微型开缝钝体燃烧器与微型常规钝体燃烧器的燃烧情况.结果表明:开缝钝体燃烧器火焰宽度一致性较好,火焰中心温度沿轴向分布更加均匀,尤其在速度较大时,开缝钝体燃烧器优势更加明显;开缝钝体燃烧器燃烧效率高于常规钝体燃烧器,速度大于25m/s时,开缝钝体燃烧器效率高出常规钝体燃烧器5%左右;由于开缝钝体中钝体缝隙过大,濒临吹熄极限时,钝体后值班火焰被吹熄,开缝钝体燃烧器吹熄极限略有降低.

In this paper, a slotted bluff-body was used to stabilize the combustion in a micro burner. The detailed chemical reaction mechanism was adopted to simulate the combustion condition in a micro combustor with a slotted or unslotted bluff-body at different feed velocities. The simulation results show that the slotted bluff-body combustor has a more uniform and stable flame, and the center temperature of the flame is more uniform along the axial direction, especially at a high feed velocity; The combustion efficiency of micro slotted bluff-body combustor is higher than that of the conventional bluff-body combustor by about 5% at a feed velocity higher than 25m/s; As the bluff-body gap is too large, the flame behind slotted bluff-body is blown off and then the whole flame extinguishes in the slotted bluff-body burner, resulting in a slightly lower blow-off limit.