电极位置与电极面积对离子电流影响的试验研究

Experimental Investigation for Influences of Electrode Location and Area on Ionic Current

在定容燃烧弹中将5个不同面积的电极安装在容弹中的不同位置,通过采用不同测量电极组合测量了燃烧过程中产生的离子电流信号。以离子电流信号、燃烧压力信号和火焰纹影照片为基础数据,分析了电极位置和电极面积对离子电流的影响。试验结果表明:电极位置会影响离子电流的出现时刻、大小、峰值及峰值时刻等特征参数;当正电极一定时,离子电流升高的次数随负电极数量的增加而增多,说明离子电流能够反映电极附近的局部燃烧信息;火焰与正电极、负电极可接触面积影响着电极吸收的电荷量及离子电流的幅值,且负电极面积的影响大于正电极面积的影响。该研究结果可为离子电流法获取发动机缸内燃烧信息的应用提供理论依据。

Five electrodes with different areas were installed at different locations of the constant volume combustion bomb. Ionic current during combustion was obtained by the combination of different measuring electrodes. The influences of electrode location and area on ionic current were analyzed according to ionic current signals, pressure signals and schlieren pictures. The experiments show that the electrode location can affect starting timing, value, peak, peak timing, etc. of ionic current. When the anode keeps constant, the number of rising signals of ionic current increases with the number of cathode, revealing that partial combustion information in the vicinity of the electrode can be extracted from ionic current. The charge absorbed by electrodes increases with the increasing anode and cathode areas. Therefore, ionic current increases with the increasing anode and cathode areas, and cathode area exerts a greater effect on ionic current than anode area, which provides a theoretical basis for application of ionic current method to measuring combustion conditions of engine.