脉动燃烧抑制乙炔扩散火焰碳烟排放的研究

Soot suppression of acetylene diffusion flamesby pulse combustion

针对乙炔燃烧高碳烟排放的问题,提出对火焰施加脉动波以抑制碳烟的生成并对抑制效果进行了研究。分析了振幅、频率、喷嘴内径、燃料流量和波形对碳烟抑制效果的影响。结果表明:随着振幅的增大,碳烟生成量明显下降;当施加频率为40 Hz、振幅为0.02 V的脉动波时,碳烟抑制率超过90%;在振幅不变的情况下,碳烟抑制率先随频率的增大而增大,在频率为40 Hz的条件下,抑制率最优,而后随频率的增大开始下降,当频率大于80 Hz时基本上不变;喷嘴内径与碳烟生成量没有明显的相关性;在其他条件不变时,采用相对较小的燃料流量,脉动对碳烟生成的抑制效果更好;在锯齿波、方波、正弦波3种波形中,方波对碳烟生成的抑制效果最好。扫描电子显微镜(scanning electron microscope,SEM)结果表明,脉动燃烧可以抑制碳烟颗粒的团聚和促进碳烟颗粒的氧化,使其颗粒变小,最终达到抑制碳烟生成的目的。因此,脉动燃烧是一种抑制碳烟生成的有效手段,可为燃烧污染控制提供参考。

In response to the problem of high soot emission from acetylene combustion,the study proposed a method of applying pulsating wave to acetylene diffusion flames to suppress the generation of soot,and then investigated the effect of amplitude,frequency,internal diameter of the nozzle,flow rate of the fuel and wave shapes on the soot suppression.The results show that with the increase of amplitude,the soot emission is decreased obviously.In case of frequency being 40 Hz and amplitude being 0.02 V,the soot suppression rate exceeds 90%.When a fixed amplitude is applied,the soot suppression rate increases with the increase of the frequency,and reaches the optimal in case of frequency being 40 Hz.From 40 to 80 Hz,the soot suppression rate is on the decline,and has no change when frequency being greater than 80Hz.The internal diameter of the nozzle has little effect on the soot suppression.When other conditions remain unchanged,the soot suppression is enhanced at a relatively lower flow rate of the fuel by pulse combustion.Among three waves shapes of saw tooth wave,square wave and sine wave,square wave has the best performance on soot suppression.The results of scanning electron microscope(SEM)show that pulse combustion can suppress agglomeration of soot particles,accelerate soot oxidation and decrease the size of soot particles,thus leading to soot suppression.Therefore,pulse combustion is an effective way to suppress the generation of soot,which can provide a reference for the combustion pollution control.