几何结构对贫油直喷燃烧室流场特性影响的研究

Effect of geometry on flow field characteristics of lean direct injection combustor

基于现有单点贫油直喷燃烧室,采用数值模拟方法研究了头部几何角度对燃烧室流场特性的影响。分别对比了冷态与燃烧态条件下不同头部几何角对燃烧室轴向速度分布、燃烧效率、总压损失等特性的影响。研究表明:在所研究的几何角度范围内,冷态下头部几何角度对回流区的长度影响很小,对回流区内轴向速度分布具有较大影响。燃烧态下随着头部几何角度的增加,回流区轴向尺寸逐渐增加,中轴线上轴向速度值逐渐降低。燃烧室的出口平均温度、燃烧效率、总压恢复系数基本保持不变,60°结构产生的NO_x生成量最低,30°结构产生的NO_x生成量最高。

The effect of geometry on the flow field characteristics of lean direct injection combustor is studied by using computational fluid dynamics（CFD）method based on the present LDI geometry.The axial velocity distribution,combustion efficiency,and pressure drop are compared with different dome geometries under the non-reacting conditions and reacting conditions.It is shown that the effect of dome geometry on the length of recirculation zone is negligible within the angle range in the study,but it changes the axial velocity distribution in the recirculation zone.Under the combustion condition,the length of recirculation zone grows with the increased dome angles,but the axial velocity decreases.The outlet temperature,combustion efficiency,and the total pressure recovery coefficient remain unchanged under different dome angles.The configuration with 60°dome geometry yields the minimal NO_x with the 30° dome geometry yields the maximum NO_x.