直交流电场对甲烷-空气预混球形扩展火焰的影响

摘要

Aerodynamic effect, thermal effect and combination effects on lfame were investigated by numerical simulation to verify the combustion assisted mechanism of DC/AC electric ifeld acting on the premixed methane-air spherical y expanding lfame. The simulation method was adding momentum source and energy source terms into the Navier-Stokes (N-S) equations on lfame surface. Some relative experiments were done to verify the simulation correctness. The results show that the aerodynamic effect including the particle motion on lfame surface and the vortexes, are the main factor that affect the lfame under DC electric ifeld. The lfame is affected by the superposition of aerodynamic effect and the thermal effect under an AC electric ifeld below 1 kHz. The lfame is only affected by the thermal effect without aerodynamic effect under an AC ifeld above 1 kHz, which is much higher than that particle response required.%为验证直流/交流电场对甲烷—空气预混球形传播火焰的助燃机理，模拟研究了火焰分别受气动效应、热效应和两者叠加作用的影响。采用的模拟方法是：向火焰锋面Navier-Stokes (N-S)方程添加动量源项和能量源项。进行了相关的实验，以验证模拟的正确性。结果表明：直流电场对火焰的影响主要是气动效应，火焰锋面内粒子的迁移和涡流是其中的主要因素。在1 kHz以下的低频交流电场中，电场对火焰的影响主要是气动效应和热效应的叠加作用。而在1 kHz以上的高频交流电场中，因该频率远高于粒子响应所需，故不存在气动效应，此时电场对火焰的影响是由热效应产生的。