Abstract:

To study the influence of the flame propagation speed on the electric field-flame effects, an experiment was conducted on the constant volume combustion bomb to investigate the effects of negative direct current electric field(U=0, -5, -10 kV) on the C₃H₈/O₂/Ar/CO₂ premixed flame with the different CO₂ blending concentrations at equivalent fuel/air ratio of 1.0, room temperature and atmospheric pressure. The CO₂ blending concentrations are 0, 10%, 15%, and 20%, respectively. Given applied electric field and mixture concentration, the flame propagation speed of C₃H₈/O₂/Ar/CO₂ flame decreases with the CO₂ blending concentrations increasing, while both the normalized flame deformation ratio and the mean change rate of the flame propagation speed increase. When U=-10 kV and C₃H₈/O₂/Ar/CO₂ flames with the CO₂ blending concentrations of 0, 10%, 15%, and 20%, the mean normalized flame deformation ratios are 1.01, 1.31, 1.80, and 3.12, respectively. The mean change rate of the flame propagation speeds are 10.87%, 17.87%, 19.16%, and 34.63%, respectively. The results show that the promoting effect of negative DC electric field on C₃H₈/O₂/Ar/CO₂ flame propagation is significantly enhanced with the decrease of flame propagation rate.

Key words: CO₂ blending concentration, direct current electric field, premixed flame, deformation ratio, flame propagation speed

摘要：

为了揭示电场对火焰效应与火焰传播速率的关系，在定容燃烧弹上研究了常温常压下、负直流电场（U=0、-5、-10 kV）对当量燃空比f为1.0的C₃H₈/O₂/Ar/CO₂预混火焰影响规律随混合气中CO₂掺混浓度（混合气中CO₂体积分数分别为0、10%、15%、20%）的变化关系。实验结果表明：给定加载电压，随着CO₂掺混浓度的增大，C₃H₈/O₂/Ar/CO₂预混火焰传播速率降低，规范化火焰变形率与平均火焰传播速率变化率均增大。当U=-10 kV时，CO₂掺混浓度为0、10%、15%、20%时对应的平均火焰变形率分别为1.01、1.31、1.80、3.12，平均火焰传播速度变化率分别为10.87%、17.87%、19.16%和34.63%。研究结果表明负直流电场对C₃H₈/O₂/Ar/CO₂火焰传播的促进效应随着火焰传播速率的降低而显著增强。

关键词: CO₂掺混浓度, 直流电场, 预混火焰, 变形率, 火焰传播速率