电场分布对球形传播火焰变形率的影响

Effects of Electric Field Distribution on Deformation Rates of Spherical Propagation Flame

针对电场作用下球形传播火焰的变形问题,利用Maxwell 14.0软件分别对点状、环状、直径为20mm和60mm的网状等4种电极产生的电场进行了模拟,同时在常温、常压下,定容燃烧弹中过量空气系数为1.2时,通过对这4种结构的电极施加负电压(-5kV和-10kV)对甲烷/空气预混火焰在不同方向(与水平方向夹角为0°、15°、30°、45°、60°和70°)上的火焰变形率进行了研究。结果显示:施加负电压时,环状电极下的火焰在不同方向上的平均变形率最小,点状电极的次之,直径为20mm网状电极比点状电极的稍大;直径为60mm网状电极下施加-5kV电压时,火焰在不同方向上的平均变形率与点状电极的差别不大,施加-10kV电压时,火焰在大于45°方向上的平均火焰变形率最大。由此表明,环状电极的电场分布有利于火焰的均匀发展,可以降低火焰淬熄的可能性。

The electric fields around point electrode,ring electrode,and mesh electrodes with diameters of 20 mm and 60 mm are simulated with Ansoft Maxwell software,and the electric field distributions in constant volume combustion bomb are obtained.An experiment is also conducted to investigate the different influences of the four electrodes under applied negative voltages（-5kV and-10kV）on the deformation rates in different directions（at angels of 0°,15°,30°,45°,60°and 70°to the plane）of premixed CH4/air mixtures at the excess air ratio of1.2room temperature and atmospheric pressure.The results show that the average flame deformation rates in different directions of the ring electrode get the minimum in the case of negative voltages,followed by point electrode and mesh electrode with diameter of 20 mm.As applied voltage of-5kV,the average flame deformation rates in different directions of the mesh electrode with diameter of 60 mm slightly differ from those of point electrode.As applied voltage of-10 kV,the average flame deformation rates over 45°get larger than those of the other electrodes and the flame deforms greatly,the electric field distribution of the ring electrode thusis beneficial for whole flame development to reduce the probability of flame quenching