大气温度对某型燃气轮机燃烧稳定性和NOx排放影响的数值研究

Numerical Study on the Influence of Atmospheric Temperature on Combustion Stability and NOx Emission of a Heavy-duty Gas Turbine

为了对比扩散和预混两种不同燃烧模式下大气温度对燃气轮机燃烧稳定性和NOx排放的影响规律,针对某重型燃气轮机燃烧室,对多旋流喷嘴燃烧室的燃烧稳定性和NOx排放进行了数值研究。结果表明:对于扩散燃烧,大气温度升高,燃烧室内高频脉动增强,燃烧稳定性变差;对于预混燃烧,大气温度升高,有利于提高燃烧的稳定性;在扩散燃烧模式下燃烧室燃料喷嘴下游回流区的温度最高,NOx生成量最大;预混燃烧下燃烧室头部温度分布较均匀,燃烧室NOx生成主要集中在驻涡回流区和燃烧室中下游位置,燃料喷嘴下游回流区NOx生成量很小;随着大气温度的升高,扩散燃烧和预混燃烧下燃烧室内NOx的生成量均增加。研究结果可为指导燃气轮机运行提供参考。

In order to compare the influence of environmental temperature on combustion stability and NOx emission under different combustion modes of a gas turbine,taking a heavy gas turbine combustor as the research object,the numerical models of full-scale combustor for the diffusion and premixed combustion were established.The combustion stability and NOx emissions of the multi-swirl nozzle combustor were numerically calculated.The results show that for the diffusion combustion,the high frequency pulsation in the combustor is enhanced after the environmental temperature rises,and the combustion stability is deteriorated.For the premixed combustion,the increase of the environmental temperature is beneficial to improve the stability of combustion;In the diffusion combustion mode,the temperature in the downstream recirculation zone of the combustor fuel nozzle is the highest,and the NOx production is also the largest.In the premixed combustion mode,the temperature distribution in the combustor head is relatively uniform,the NOx formation in the combustor is mainly concentrated in the trapped vortex recirculation zone and the middle and downstream of the combustor,the NOx formation in the downstream recirculation zone of the fuel nozzle is small;As the environmental temperature increases,the amount of NOx generated in the combustor increases under both diffusion and premixed combustion.The research results provide a reference for guiding the operation of gas turbines.