双旋流燃烧室主燃区流动特性PIV测量和分析 *

PIV Measurement and Analysis of Flow Characteristic in Primary Zone with Dual-Swirl Combustor

关键词:  燃烧室  主燃区  回流区  反向旋流  同向旋流  主燃射流  粒子成像测速仪(PIV)

Key words:  Combustor  Primary zone  Recirculation zone  Counter-swirl  Co-swirl  Primary jet  Particle image velocimety(PIV)

摘要:

针对采用斜切径向双级旋流器的环形燃烧室单头部矩形模型，利用非接触式测量方法粒子成像测速仪(PIV)测量了主燃区的300K冷态速度场。采用Realizable κ-? 湍流模型和稳态层流火焰面燃烧模型对燃烧室的冷流和燃烧流场进行数值模拟，得到燃烧室流场的速度分布和流场结构，并与试验测量数据进行对比验证。结果表明:瞬态流场结构变化剧烈，旋流和主燃射流的边界形成大量小尺度漩涡结构，回流区具有强烈的搅拌作用，回流区下游滞止点位置是随机变化的；反向旋流器比同向旋流器产生的回流区尺寸更小，燃烧状态的回流区尺寸比冷流的小，但主要受火焰筒壁面和主燃射流的约束；外旋流在距离头部5mm距离内控制内旋流，保持旋向相同；燃烧增大主燃射流穿透深度，改变流场的对称性。

Abstract:

For a single-dome annular combustor rectangular model with dual-swirler，including discrete jets and radial swirler，the velocity field in primary zone was measured with Particle Image Velocimetry(PIV) in isothermal condition with 300K. The isothermal and reacting flowfield of combustor were simulated with Realizable κ-? turbulent model and Steady Laminar Flamelet combustion model，obtaining distribution of velocity and flowfield structure，which are compared with the experiment results. The results indicate that instantaneous flowfield changes rapidly. A large number of small-scale vortex are formed along the boundary of swirl flow and primary jet illustrating the strongly stirring effect of recirculation zone，and instantaneous rear stagnation point is random. The size of recirculation zone generated by counter-swirler is smaller than that generated by co-swirler，and the size of recirculation zone in reacting condition is smaller than that in isothermal condition. However，the size of recirculation zone is primarily controlled by liner and primary jet. The outer swirl flow can control the inner swirl flow in 5mm from the exit of the dome，keeping the same direction as outer swirl flow. Combustion can increase the penetration depth of primary jet and change the symmetry property of flowfield.