负电场下点电极和网状电极对预混稀燃火焰的影响

Effect of Point and Mesh Electrodes with Applied Negative Voltage on Premixed Lean Combustion

针对相同能耗下电极形状对火焰的影响,研究了常温、常压下定容燃烧弹中过量空气系数为1.6时甲烷空气预混稀燃火焰的传播和燃烧特性与加载电压的关系,对比了点电极和网状电极对火焰的影响。结果表明:2种电极下加载电压都使得火焰发生了形变,对火焰横向传播均有明显的促进作用;与未加载电压相比,当加载电压为-5、-10、-12kV时,点电极下火焰纵向传播速度分别提高9.32%、17.20%、4.67%,网状电极下分别提高0.62%、-20.90%、-22.80%,点电极下压力峰值增幅分别为6.4%、9.8%、11.2%,网状电极下增幅分别为5.6%、2.4%、1.3%;加载-5kV电压时2种电极对火焰的影响相差不大,加载-10、-12kV电压时点电极对火焰的促进作用明显优于网状电极。综合考虑可以得出,点电极的性能更加优越。

An experiment was conducted to investigate the different influences of the point electrode and the mesh electrode with applied voltages on the flame propagation and combustion characteristics of premixed CH4/air mixtures at the excess air ratio of 1.6, room temperature, and atmospheric pressure. The results show that the flame shape deformed and the horizontal flame speed significantly increased when the vohage was applied to the two kinds of electrodes. Compared with those without the applied voltage, when the applied vohage was --5 kV, --10 kV and --12 kV, the vertical flame speed of the point electrode increased by 9.32%, 17.20% and 4.67% while that of the mesh electrode increased by 0.62%, --20.9% and --22.8%, respectively; the peak pressure of the point electrode rose by 6.4%, 9.8%, 11.2 % while that of the mesh electrode rose by 5.6 %, 2.4 % and 1.3 %, respectively. The two electrodes had slightly different effect on the flame at the input voltage of --5 kV while the point electrode was more beneficial to the flame propagation and combustion at the input voltages of --10 kV and --12 kV. It is likely that the point electrode performed better.