贫油直喷燃烧室燃烧稳定性的数值研究  

Numerical Study on Combustion Instability in Lean Direct Injection Combustor

作　　者：洪挺[1] 张文普[1] 

机构地区：[1]浙江大学航空航天学院力学系,浙江省杭州市310027

出　　处：《中国电机工程学报》2013年第2期24-30,7,共7页Proceedings of the CSEE

基　　金：国防基础科研计划项目(A1420080144)~~

摘　　要：贫油燃烧过程中很容易产生振荡燃烧现象,而振荡燃烧则会进一步影响燃烧室中氮氧化物(nitrogen oxides,NOx)的生成与排放。为了研究振荡燃烧的触发机制及其对NOx生成与排放的影响,利用FLUENT中的离散相模型、非预混燃烧模型和混合分数/PDF平衡化学反应模型,对贫油直喷燃烧室内的航空煤油/空气非预混燃烧进行了大涡数值模拟,亚网格模型采用WALE模型。将计算与实验值进行比较发现:在喷嘴附近区域,数值结果与预测结果略有差异,在其他区域,数值计算的各个物理参量值都与实验值非常吻合。通过改变入口空气流速,触发了振荡燃烧,其主频为560和1200Hz。对燃烧稳定性的模拟表明,可以通过调整燃烧室的入口条件来激励或者抑制振荡燃烧现象的出现。在此基础上分别计算了稳定燃烧和不稳定燃烧时的NOx排放,结果表明振荡燃烧现象的出现明显改变了NOx的生成与排放。Lean direct injection（LDI） combustion increases the occurrence probability of oscillation combustion, which affects the production and emission of nitrogen oxides （NOx）. In order to study the mechanism of oscillation combustion and its impact on the production and emission of NOx, Large eddy simulation （LES） was applied in FLUENT with non-premixed combustion model, discrete phase model （DPM）, mixture fraction/PDF equilibrium chemistry model and WALE subgrid-scale model to simulate the combustion of kerosene and air in a lean direct injection combustor. The results are little different from that of experimental measurements in the areas near the injection, while they agree well with the experimental results in the other areas. The combustion became unstable while the inlet air velocity changed, and the oscillation frequencies were 560 Hz and 1 200 Hz. It means that combustion instability should be induced by disturbance of equivalence ratio. In addition, both in stable and unstable combustion processes, nitrogen oxides emissions were calculated, which were mutually different. It means that combustion instability can have an obvious effect on production and emission of NOx.

关 键 词：贫油直喷燃烧室 大涡模拟 不稳定燃烧 NOx 排放 

分 类 号：TK16[动力工程及工程热物理—热能工程]