贫燃料预混燃烧的回火特性研究

FLASHBACK CHARACTERISTICS OF LEAN PREMIXED COMBUSTION

回火问题是贫燃料预混燃烧面临的主要问题之一。本文采用计算和实验相结合的方法研究甲烷与富氢合成气贫预混燃烧的回火现象,得到不同燃料、不同稳定方式之间的回火特性。研究结果表明,回火极限可以关联为丕雷数模型,环形稳定器的回火稳定性最好,其次为杆稳定器,旋流稳定器的稳定性最差;环形稳定的甲烷预混火焰的回火过程为边缘稳定,适当加入边缘空气同轴射流后变为中心回火,且同轴射流速度存在最佳范围可以提高回火稳定性。

Flashback is one of the major problems in lean premixed combustion of gas turbine combustor. Mechanism and characteristics of methane and syngas flashback for 3 types of flame holders, i.e. ring shape, rod shape and swirl have been researched through experiment as well as numerical simulation. Experiments demonstrate that, the flashback velocity of different fuel composition or flame holder size generally can be correlated to the same dimensionless function by using Peclet number model if the structures of flame holders are the same. Peclet function curves were used to compare the anti-flashback performance of the 3 types of flame holders above. Boundary coaxial jet can change the mode of the flashback from boundary layer flashback into core flow flashback and significantly improve the anti-flashback performance of the ring-type flame holder on condition that the flow rate of is in an optimal range. As the result, ring shape holder shows the best while swirl holder the worst on anti-flashback performance.