多孔介质稳焰器对旋流火焰振荡燃烧特性影响的试验研究

为研究多孔介质稳焰器孔密度变化对贫预混旋流火焰振荡燃烧特性的影响，通过光电倍增管测量全局火焰热释放率，采用双麦克风方法测量旋流器入口速度脉动，获得不同孔密度多孔介质稳焰器火焰传递函数；并通过高速相机测量不同孔密度多孔介质稳焰器振荡火焰结构的变化。试验结果表明：多孔介质能够改变燃烧室声模态，有效抑制燃烧振荡，但孔密度对受迫燃烧火焰热释放率和压力脉动影响具有非线性；高频入口扰动对火焰响应特性影响较弱，火焰受迫响应呈现低通滤波特性；火焰传递函数增益峰值对应入口激励频率存在差异，但相位分布斜率基本一致；多孔介质导致火焰向稳焰器中心轴线聚拢，相干结构更加明显；宽频扰动范围内的火焰张角分布趋势与火焰传递函数增益曲线的分布趋势相反。

Experimental Study on the Effect of Porous Medium Burner on Oscillating Combustion Characteristics of Swirl Flame

In order to study the effect of pore density variation of porous medium burners on the forced response characteristics of lean premixed swirl combustion flames,the global flame heat release rate was measured by a photomultiplier tube.The two microphone method was used to measure the inlet velocity pulsation of the nozzle,and the flame transfer function of the porous medium burner with different pore densities was obtained.The changes of the oscillating flame structure of the porous medium burner with different pore densities were measured by a high speed camera.The experimental results indicate the porous medium can change the acoustic mode of combustor and inhibit combustion oscillation effectively,while the effect of pore density on the forced flame heat release rate and pressure pulse is nonlinear; the high frequency inlet disturbance has a weaker effect on the flame response characteristics,and the forced flame response exhibits low pass filtering characteristics;the inlet excitation frequencies corresponding to peak value of the flame transfer function gain are different,but the phase distribution slopes are basically the same;the porous medium causes the flame to converge toward the central axis of the burner,and the coherent structure in the flame becomes more obvious.The trend of flame angle distribution is exactly opposite to that of flame transfer function gain curve in the range of broadband disturbance.