重型燃气轮机燃烧过程的反应动力学数值模拟

Reaction Kinetic Simulation of Combustion Process

关键词:  重型燃气轮机  甲烷  燃烧特性  反应动力学特性

Key words:  Large scale  Methane  Combustion characteristics  Reaction kinetic characteristics

摘要:

为了阐明重型燃气轮机燃烧过程的反应动力学特性，采用Gri_3.0，NUI_Galway与USC_2.0动力学模型对甲烷燃料在定容燃烧反应器中的燃烧特性进行了数值计算，并与实验结果进行了对比分析，确定了甲烷燃料的反应动力学模型；耦合该反应动力学模型与CFD计算软件，对燃用甲烷燃料的重型燃气轮机燃烧室单个火焰筒的燃烧过程进行了反应动力学分析，并与相应实验结果进行了对比分析。结果表明:与NUI_Galway及USC_2.0动力学模型相比，采用Gri_3.0动力学模型计算得到的甲烷燃料多工况下的燃烧特性与实验值吻合较好；在该重型燃气轮机燃烧室单个火焰筒中，在火焰筒头部与主燃区同时存在两个明显的呈对称状态的回流区；在该火焰筒中的高温区域，O，OH与H等活性组分以及CO₂的摩尔分数达到最大，而在低温区域CO的摩尔分数达到最大；同时，与实验值相比，采用Gri_3.0动力学模型计算得到的单个火焰筒的出口平均温度略高约4K，热点温度高约197K。

Abstract:

In order to illustrate the reaction kinetic characteristics of the combustion process in large scale gas turbine，the combustion characteristics of methane in the constant volume combustor were simulated using the Gri_3.0，NUI_Galway and USC_2.0 reaction mechanisms. At the same time，the computed results were compared with the experimental data，and the reaction mechanism of methane was determined. The reaction kinetic characteristics of combustion process in a flame tube of the gas turbine were analyzed by combining this reaction mechanism with the CFD，and the computed results were compared with the experimental data. The results show that compared with the NUI_Galway and USC_2.0 mechanisms，the combustion characteristics of methane at some conditions simulated using the Gri_3.0 reaction mechanism agree well with the experimental data. Furthermore，there are two symmetric recirculation zones at the flame tube head and in the primary combustion zone of the flame tube，respectively. The mole fractions of active components (such as O，OH and H) and CO₂ are maximum at high temperature zone. However，the mole fraction of CO is the maximum at the low temperature zone. At the same time，compared with the experimental data，the outlet average and maximum temperature of the flame tube simulated by the Gri_3.0 reaction mechanism are higher about 4K and 197K，respectively.