壁面微通道冷却对旋流燃烧室性能影响实验

为了探索微通道高效换热技术在低污染燃烧室壁面冷却中的应用,实验研究了壁面微通道冷却对模型旋流燃烧室性能的影响。结果表明:微通道结构对燃烧室热壁面具有显著的冷却效果,在雷诺数小于350时,雷诺数增加对壁面冷却有明显提升作用,在雷诺数大于350后,雷诺数的增大对冷却效果提高的促进作用减小；雷诺数增大对相同进气工况下CH*化学发光信号表征的火焰时均结构几乎不产生影响,但在个别工况下会使火焰产生黄色火星,甚至间歇地产生黄色火焰,带来不完全的燃烧；雷诺数增大会增强微通道对流换热程度,加大壁面传热速率,加剧火焰和微通道换热间的相互作用,使火焰表面发生较大的热量损失,最终造成CO排放量增加,NOx排放量降低,并使整体燃烧效率下降。 

Experiment on effects of wall cooling with microchannels on performances of swirl combustor

In order to explore the cooling application of microchannels in gas turbine lower emissions combustors, the effects of wall cooling with microchannels on the performances of swirl combustor were studied with water as the coolant. Results showed that the microchannels had significant cooling effect on the combustor walls with high temperature. When Reynolds number of coolant passing through microchannels was less than 350, the increase of Reynolds number of coolant had a significant influence on the decrease of wall temperature, but when Reynolds number was greater than 350, the decrease of wall temperature was almost negligible as the flow rate increased. At fixed values of air mass flow rate and equivalent ratio, the flame structures characterized by CH* chemiluminescence signal hardly changed as Reynolds number of coolant increased, but swirl flame contained yellow sparks or even yellow flame, leading to incomplete combustion in a relatively high Reynolds number. As Reynolds number of coolant increased, the heat transfer rate of wall was raised, which enhanced the interaction between the flame and heat transfer of microchannels during combustion and led to results such as bigger heat loss on the flame surface, more CO emission, less NOx emission and lower overall efficiency of swirl combustion.