为了比较不同频率的高频交流电场在辅助燃烧方面的作用,对常温、常压下定容燃烧弹中网状电极结构下的电场对甲烷/空气预混稀燃火焰的火焰形状、火焰传播速度、燃烧压力的影响进行研究.结果表明:在高频交流电场作用下,火焰均在水平方向被拉伸,且频率越高,拉伸越剧烈,平均火焰传播速度和燃烧压力均随着交流电频率的增加而增加;混合气越稀,电场对火焰的作用效果越明显,与未加电压相比,当交流电压有效值为5kV,交流电频率为25kHz,过量空气系数为1.2、1.4和1.6时,平均火焰传播速度分别提高45.77%、50.00%和87.93%,相对燃烧压力增大率的最大值分别为0.51、0.66和0.86.
An experiment was conducted in a constant volume combustion bomb under a lean combustion condition to compare the roles of different frequencies of high-frequency alternating electric fields in promoting combustion process. The different effects of high-frequency alternating electric fields with the mesh electrode on the flame shape, propagation speed and combustion pressure of premixed CH4/air mixtures were also analyzed at room temperature and atmospheric pressure. The results show that the flame is stretched in the horizontal when high-frequency alternating electric field is applied to the electrodes and is stretched more severely with the frequency increase. The average flame propagation speed and combustion pressure also increase with the frequency. In addition, the effect of electric field on the flame is greater when the mixture is diluted. Compared with those without the applied voltage, when the voltage virtual value is 5 kV and the frequency is 25 kHz, the average flame propagation speeds at the excess air ratio of 1.2, 1.4 and 1.6 increase by 45.77 %, 50.00 % and 87.93 % ; the maxima of the increasing rate of relative combustion pressure are 0.51, 0.66 and 0. 86, respectively.