预混层流燃烧中离子电流与火焰传播速度的相关性研究

在当量空燃比φa=1、初始压力P0=0.1MPa、初始温度T0=300K、离子电流装置偏置电压U=400V的条件下,对压缩天然气掺氢(CNG+H2)、液化石油气(LPG)、二甲醚(DME)在定容燃烧弹中的球形火焰燃烧过程进行了分析,分别测量了三种燃料的层流火焰传播速度、离子电流以及燃烧压力,利用相关性原理探讨了预混层流火焰传播速度与离子电流之间的关系,研究结果表明:正常燃烧的离子电流通常由点火、火焰前锋以及焰后区三部分组成,而火焰传播速度与焰后区离子电流峰值的样本相关系数在0.51～0.95之间.因此,三种燃料焰后区的离子电流峰值与层流火焰传播速度之间均存在一定的相关性.

The correlation of ionic current and flame propagation speed

Spherically, expanding flames of mathane-hydrogen (hythane) and liquefied petroleum gas (LPG) and dimethyl ether (DME) were analysed in a constant volume combustion bomb at the initial condition of equivalence fuel-air ratio φa=1, pressure P0=0.1MPa and temperature T0=300K. The laminar flame speed, ionization current and pressure of three fuels were measured, respectively. The correlation theory principle is used to establish the relationship between premixed laminar flame propagation speed and the ionization current. The results show that the time history of the ionization current consists of three phases, I.e. Ignition, flame front and post flame, within a normal ignition and combustion processes. The correlation coefficient between flame propagation speed and the current peak during post flame phase is from 0.51 to 0.95. Therefore, the post flame current peak can be used to forecast laminar flame speed for the three fuels.