致密发散孔冷却环形折流甩油盘燃烧室设计研究

Design Investigation of Annular Combustor with Slinger and Compacted Effusion Cooling Holes

为了研究致密发散小孔冷却环形折流燃烧室的设计方法,根据火焰筒头部无冷却时的流场形态及期望引导的流场形态,对头部壁面发散小孔进行了两种对比性设计。为对比两种方案的优劣,对设计后的燃烧室进行了数值模拟。结果表明通过增加发散小孔,调节内外环射流孔的气量分配,可成功诱导出期望的多涡流场,且方案2的发散小孔冷却效果更佳。证明通过调整内外环发散小孔开孔数量来调节射流孔的射流穿透深度,并结合甩油盘油雾诱导理想的主燃区流场形成是可行的;采用孔倾角为钝角的发散小孔可更好地保护热负荷压力大的前几排火焰筒壁面;通过在高温区增大孔阵疏密度,把高温区处的发散小孔孔径由原先的0.68mm减小至0.3~0.55mm,可实现在不改变冷气流量的前提下,增强换热,降低壁面温度。

In order to design annular combustor with slinger and compacted effusion cooling holes,two kinds of comparative methods on effusion cooling holes are conducted according to the flow field of flame tube without effusion cooling holes and the desirable multi-vortexes flow field. For comparing the effectiveness of these two methods,the combustion field of combustors has been simulated. The computational results indicate that adding the number of effusion holes to adjust the gas distribution of jet holes of outer and inner liner can induce the multi-vortexes flow fields,and the cooling effectiveness of method 2 is better. It shows that adjusting the number of holes to change the air penetration distance of jet holes and using the atomized fuel from slinger can induce the desirable flow field. The effusion cooling holes with obtuse angle to the mainstream can protect the first rows of flame tube with large heat load better. Increasing porosity of holes array and changing the diameter of holes from 0.68 mm to 0.3~0.55 mm can enhance heat transfer and reduce the wall temperature without changing cooling air mass flow.