Abstract:

The effect of DC electric field on methane/air premixed flame was studied under the room temperature (298 K) and initial pressure P_initial of 0.1-0.5 MPa. The results are as follows. The flame is mainly stretched in the horizontal direction with the applied voltage under different initial pressures. The change of the flame deformation increases with the voltage amplitude. The flame instability increases with the initial pressure. Compared to without the applied voltage, the flame propagation speed is improved obviously with the applied voltage, and the enhancement in flame propagation speed increases with the voltage amplitude and initial pressure, so the effect of the electric fields on the flame increases with the initial pressure. When λ=1.4,U=-10 kV,and P_initial=0.1-0.5 MPa, the average flame propagation speed increases by 35.67%-52.71%. The enhancement in the mass burning rate increases with the voltage amplitude and the initial pressure with the applied voltage. The initial burning period and the main combustion period are shortened with the applied voltage, and the decrease in them increase with the initial pressure, and the change of the initial burning period is more obvious.

Key words: initial pressure, methane, air, direct current electric field, constant volume combustion bomb, flame propagation speed, combustion pressure

摘要：

在定容燃烧弹中研究了常温（298 K），初始压力P_initial为0.1～0.5 MPa，加载U=-5、-10 kV直流电场对甲烷/空气预混火焰燃烧特性的影响。结果表明：不同初始压力下，加载电压，火焰主要在水平方向发生拉伸变形，加载电压幅值越高，火焰变形越明显，初始压力越高，火焰不稳定性增加，火焰面褶皱增加。加载电压后，火焰传播速率明显提高，电压幅值增大，其提高程度逐渐明显，初始压力增大，其提高程度更加明显，电场对火焰的促进效果更加明显，λ=1.4，U=-10 kV，P_initial=0.1～0.5 MPa时，平均火焰传播速率分别提高35.67%～52.71%。相对于未加载电压，加载电压后，各初始压力下质量燃烧率均增大，随电压幅值升高而升高，且初始压力越大，质量燃烧率变化越明显；火焰的初始燃烧期和主燃烧期均缩短，初始压力越高，缩短程度也越明显，二者相比，初始燃烧期缩短的程度更为明显。

关键词: 初始压力, 甲烷, 空气, 直流电场, 定容燃烧弹, 火焰传播速率, 燃烧压力