LPP燃烧室振荡燃烧机理及二次燃料对振荡的抑制

Mechanism Governing the Oscillationand Combustion in a LPP Combustor and Suppression on the Oscillation Exerted by the Secondary Fuel

开展了贫预混合预蒸发燃烧室（LPP）振荡燃烧机理的实验研究,利用锁相的平面激光诱导荧光（PLIF）测量技术测量了一个振荡燃烧周期内不同相位上贫预混合预蒸发燃烧室火焰结构。研究表明：靠近燃烧室轴线处火焰会间歇性地局部熄灭、重新点燃、逐渐增强;远离燃烧室轴线处火焰会周期性地脱体和融合;计算了LPP燃烧室内瑞利指数分布,瑞利指数为正的两个区域与靠近燃烧室轴线处和远离燃烧室轴线处发生周期性波动的火焰区域重合;确定了LPP燃烧室中的振荡燃烧是由上述两个区域的火焰周期性波动共同作用所激励;通过二次燃料喷射,成功地抑制了LPP燃烧室内的振荡燃烧,实现了振荡燃烧的主动控制。

Experimentally studied was the mechanism governing the oscillation and combustion in a lean premixed prevaporized （LPP） combustor. In this connection, the phase-locked PLIF measurement tech- nology was employed to measure the flame configuration in the lean premixed prevaporized combustor at various phases in an oscillation and combustion period. It has been found that an intermittent local extinc- tion, reignition and gradual intensification of the flame may occur at locations close to the axial line of the combustor and a periodical separation and fusion of the flame may appear at locations away from the axial line of the eombustor. The Rayleigh indexes inside the LPP combustor were calculated and the two zones with positive Rayleigh indexes were superposed with the flame zones where a periodical fluctuation hap- pened at locations close to and away from the axial line of the combustor. It has been determined that the oscillation and combustion inside the LPP combustor were excited by a joint action of the flame in a peri- odical fluctuation in both zones. Through a secondary jet of the fuel, the oscillation and combustion inside the LPP combustor were successfully restrained, therefore, realizing an active control over the oscillation and combustion.