预混段出口角度对旋流预混燃烧特性影响

Numerical simulation of influence of premixed section exit angle on swirl premixed combustion characteristics

采用数值模拟研究了预混段出口角度对某燃气轮机燃烧室旋流预混燃烧特性的影响,分析了不同预混段出口角度下燃烧室内的流场、温度场、CH4分布及NOx生成特性。结果表明:随着预混段出口角度的增大,轴向速度减小,回流速度下降,预混段出口处回流区变宽,总回流区面积减小,角回流区逐渐消失,回流强度减弱;CH4逐渐向角回流区扩散,火焰长度有所延长,高温区范围扩大,出口处NOx摩尔分数逐渐升高,而CO摩尔分数变化则相反;在进口参数相同的情况下,最为合理的预混段出口角度为12°。

Numerical simulation was conducted to investigate the effect of the premixed section exit angle on swirling premixed combustion characteristics of a gas turbine combustor, and the flow field, temperature field,CH4 distribution and NO_x generation characteristics in the combustion chamber at different exit angles of the premixed section were analyzed. The results show that, as the angle of exit of the premixed section increases, the axial velocity decreases, the reflux velocity reduces, the recirculation zone at the exit of the premixed zone broadens, the area of the total recirculation zone decreases, the angular recirculation zone disappears gradually,and the reflow intensity weakens. CH4 gradually diffused into the corner recirculation zone, the length of the flame extended, the range of the high-temperature zone expanded, and the NO_x mole fraction at the outlet gradually increased, while the CO mole fraction changed the opposite. In the case with the same inlet parameters,the most reasonable premixed section exit angle is 12°.