环形中心钝体驻涡燃烧室进气方式研究

Study of Air Injection Mode in an Annular Central Bluff-body Trapped Vortex Combustor

关键词:  燃烧室  驻涡腔  进气方式  冷态流场  数值模拟

Key words:  Combustor  Trapped vortex cavity  Injection mode  Cold flow field  Numerical simulation

摘要:

采用FLUENT软件对两种驻涡腔进气方式时环形中心钝体驻涡燃烧室的冷态流场进行了数值模拟，并对两种驻涡腔进气方式时环形中心钝体驻涡燃烧室驻涡腔内的旋涡结构、平均流动参数以及燃烧室总体性能等进行了对比分析。结果表明:两种进气方式时，环形中心钝体驻涡燃烧室驻涡腔内均能形成相对稳定的涡系结构，进气方式由后钝体中心逆流进气变为前钝体中心顺流进气时，驻涡腔内涡系结构由单对涡转变为双对涡；与后钝体中心逆流进气相比，前钝体中心顺流进气时，燃烧室总压损失系数、驻涡腔平均静压和总压分别增加约1.345%，8.207%和6.479%，驻涡腔平均速度降低约48.423%；驻涡腔进气方式的变化对燃烧室出口气流参数沿流道高度方向的变化趋势影响不大。

Abstract:

FLUENT software was adopted to simulate the cold flow field of an annular central bluff-body trapped vortex combustor with two kinds of trapped vortex cavity injection mode. The vortex structure，averaged flow parameters of the trapped vortex cavity and the performance of the annular central bluff-body trapped vortex combustor under two kinds of trapped vortex cavity injection mode were comparatively analyzed. It has been found that the relatively stable vortex structure can all be formed in the trapped vortex cavity under both kinds of injection mode. When the injection mode changes from central upstream injection of aft-bluff-body to central downstream injection of fore-bluff-body，the vortex structure in the trapped vortex cavity changes from single vortex pairs to double. Compared with central upstream injection of aft-bluff-body，the total pressure loss coefficient of the combustor，averaged static pressure and total pressure of the trapped vortex cavity are increased by 1.345%，8.207% and 6.479%，respectively，but the averaged velocity of the trapped vortex cavity is decreased by 48.423% under central downstream injection of fore-bluff-body. The injection mode of the trapped vortex cavity 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.