同轴分级环形燃烧室低工况燃料分配特性

Fuel Distribution Strategies of Coaxial Stage Annular Combustor under Low Load Condition

针对天然气燃气轮机在低工况下的燃料分配策略问题,采用数值模拟研究了7种不同燃料分配模式下的同轴分级环形燃烧室燃烧特性,重点分析了燃料分配模式对速度场、燃料空间分布、温度场以及综合性能的影响。研究结果表明:燃料分配模式是影响燃烧室性能的关键因素,适量控制值班级燃料喷射量可以改善燃烧室内的燃料贯穿深度和温度场分布;预混级虽然可以提高燃料分布均匀性和降低污染物排放,但是会引发回火现象;当燃料通过第一、二级预混级喷入燃烧室时,燃烧室的效率较高、压力损失较小、污染物排放较低。

In order to solve the problems of fuel distribution strategies of natural gas based gas turbine under low load condition,the combustion characteristics of coaxial stage annular combustor under seven different fuel distribution modes have been studied by numerical simulation.The effects of fuel distribution mode on velocity field,fuel spatial distribution,temperature field and comprehensive performance have been analyzed in detail.The results show that the fuel distribution mode is a key factor affecting the performance of combustor,and the fuel penetration depth and temperature field distribution in combustor can be improved by proper control of pilot fuel injection.Although the premixing stage can improve the uniformity of fuel distribution and reduce the emission of pollutants,it will lead to the occurrence of backfire.When the fuel is injected into the combustor through the first and second premixing stages,the efficiency of the combustor is higher,the pressure loss is smaller,and the emission of pollutants is lower.