富油/焠熄/贫油(RQL)燃烧室燃烧和排放特性的实验研究

Experimental Investigation on Combustion and Emission Characteristics of Rich-Burn/Quick-Quench/Lean-Burn

关键词:  燃烧室  焠熄  低排放  富油燃烧  贫油燃烧

Key words:  RQL combustor  Quench  Low emission  Rich burn  Lean burn

摘要:

针对燃气轮机低排放燃烧室的研究，设计了以甲烷为燃料采用预混燃烧的富油/焠熄/贫油(RQL)模型燃烧室。通过对RQL模型燃烧室内轴向温度和组分浓度分布，燃烧室出口温度分布及排放进行实验研究，分析了焠熄与主流空气流量之比，富油区当量比对燃烧性能和排放特性的影响规律。结果表明:典型RQL燃烧方式下富油区火焰颜色较暗，贫油区火焰为淡蓝色，燃烧室内轴线方向温度呈M型分布，NO_x主要在焠熄区生成。CO，UHC和O₂浓度在经历焠熄区时发生突变；出口NO_x和CO排放都较低。保持头部当量比不变，随着焠熄与主流空气流量比的增加，燃烧室出口平均温度下降，NO_x排放下降，CO排放上升。保持焠熄与主流空气流量比不变，富油区当量比小于1.4时，不能再实现RQL燃烧模式。

Abstract:

A methane-fueled premixed rich-burn/quick-quench/lean-burn(RQL)model combustor was designed to inspect its low emission advantage in gas turbine applications. Experiments were conducted to characterize the temperature and gas composition distribution in the streamwise direction in the RQL combustor as well as the temperature distribution and emissions at the outlet of the combustor. The effects of the flowrate ratio of quench air to mainstream air and equivalence ratio in the rich zone on the combustion and emission characteristics were analyzed. Results show that dark flame combustion and the pale blue flame are presented in the rich-burn zone and lean-burn zone respectively in a typical RQL combustion. Temperature distribution in the streamwise direction presents to be M-type，and NO_x is mainly produced in the quench zone. Besides，concentration of CO，UHC and O₂ will experience a sudden decline when going across the quench zone. The outlet emission of NO_x and CO of the combustor is extremely low. When equivalence ratio in the rich zone is kept constant，the mean outlet temperature and NO_x emission decrease while CO emission increases with flowrate ratio of quench air to mainstream air increasing. And when flowrate ratio of quench air to mainstream is kept constant and equivalence ratio in the rich zone is less than 1.4，RQL combustion mode cannot be realized.