Large-Scale Vortical Motion and Pressure Fluctuation in Noise-Controlled, Swirl-Stabilized Combustor
Large-Scale Vortical Motion and Pressure Fluctuation in Noise-Controlled, Swirl-Stabilized Combustor
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DOI：
10.1299/jtst.4.494
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发表时间：
2009
影响因子：
1.2
通讯作者：
M. Shimura;M. Tanahashi;G. Choi;T. Miyauchi
中科院分区：
文献类型：
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作者：
M. Shimura;M. Tanahashi;G. Choi;T. Miyauchi
为了阐明二次喷油对燃烧振荡、燃烧噪声及其抑制机理，在连续二次喷油无控制和有噪声控制的涡流稳定湍流预混火焰的多个平面上同时进行了立体粒子成像测速（SPIV）和燃烧室压力波动的测量。SPIV测量的速度在压力波动的8个阶段进行平均，并由相平均速度得到流线。在无控制的情况下，低压阶段在燃烧室轴向中心线周围区域和旋流喷管外缘区域产生大规模的旋涡结构。随着压力的增大，它们在前人研究中得到的平均进度变量c = 0.5的等值面附近移动。这些大尺度的涡旋运动引起了火焰锋面的波动，增强了声源的熵项。二次喷射抑制了内循环区的速度波动，从而降低了燃烧噪声。结果表明，控制大范围的涡流运动对降低燃烧噪声具有重要意义。
To clarify the mechanisms of combustion oscillation, combustion noise and their suppression by secondary fuel injection, simultaneous measurements of stereoscopic particle image velocimetry (SPIV) and pressure fluctuation in combustion chamber were conducted on several planes of a swirl-stabilized turbulent premixed flame for no control case and noise-controlled case by continuous secondary fuel injection. Velocities measured by SPIV were averaged in 8 phases of the pressure fluctuation and streamlines were obtained from the phase-averaged velocities. For no control case, large-scale vortical structures are generated in regions around the axial centerline of the combustor and outer edge of the swirl nozzle in the phase of low pressure. With increasing pressure, they move near the contour surface of mean progress variable c = 0.5 which have been obtained in the previous study. These large-scale vortical motions induce fluctuation of flame front and enhance entropy term in the acoustic sound source. The secondary fuel injection suppresses the velocity fluctuation in the inner recirculation zone, resulting in reduction of combustion noise. These results show that control of the large-scale vortical motion is important for reduction of combustion noise.