环形中心钝体驻涡燃烧室后钝体进气位置研究

Study of air injection position on aft-bluff-body in an annular central bluff-body trapped vortex combustor

采用Fluent软件对驻涡腔不同后钝体进气位置时冷态条件下环形中心钝体驻涡燃烧室流场进行数值研究.详细分析了不同后钝体进气位置时,环形中心钝体驻涡燃烧室典型截面的压力与流线分布,并对不同后钝体进气位置时驻涡腔内的流线、平均速度、平均静压以及燃烧室总压损失系数的变化规律进行比较.结果表明:不同后钝体进气位置时,驻涡腔内均形成了4个旋涡,但驻涡腔内旋涡的大小、形状和位置略有不同;在各个后钝体进气位置时,驻涡腔内的平均速度随后钝体进气位置向驻涡腔外侧偏移逐渐减小,平均静压、平均湍流度逐渐增大;燃烧室出口总压损失在后钝体进气位置为1.5时出现最小值,在后钝体进气位置为0.75时其次,其值为0.0799;燃烧室出口总压和出口气流速度沿径向随后钝体进气位置改变变化不大.

The flow field of an annular central bluff-body trapped vortex combustor with different air injection position on aft-bluff-body was simulated by using the fluent software.Streamlines and pressure distribution on typical cross-section were analyzed in detail under different air injection position on aft-bluff-body. The vortex structure,averaged flow parameters of the trapped vortex cavity and the performance of the annular central bluff-body trapped vortex combustor under different air injection position on aft-bluff-body were comparatively analyzed. Results show that the relatively stable vortex structure can all be formed in the trapped vortex cavity under different air injection position,except the slightly different in size,shape and position of the vortex in the trapped vortex cavity.With air injection position moving outside,the average velocity in the trapped vortex cavity decreases,and the average static pressure and averaged turbulence intensity increases. The total pressure loss coefficient of the combustor is minimal when air injection position on aft-bluff-body is 1. 5,followed is when the air injection position on aft-bluff-body is 0. 75 with a value 0. 0799. The air injection position on aft-bluffbody has little influence on changing trend of flow parameters along flow-path height direction at the exit of the annular central bluff body trapped vortex combustor.