Effect of Nanosecond Repetitively Pulsed Discharges on the Dynamics of a Swirl-Stabilized Lean Premixed Flame
Effect of Nanosecond Repetitively Pulsed Discharges on the Dynamics of a Swirl-Stabilized Lean Premixed Flame
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DOI：
10.1115/1.4024961
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发表时间：
2013-10
影响因子：
1.5
通讯作者：
D. Lacoste;J. Moeck;D. Durox;C. Laux;T. Schuller
中科院分区：
文献类型：
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作者：
D. Lacoste;J. Moeck;D. Durox;C. Laux;T. Schuller
实验研究了纳秒重复脉冲（NRP）等离子体放电对涡流稳定贫预混火焰动力学的影响。8千伏振幅和10纳秒持续时间的电压脉冲以30千赫的重复率施加。等离子体沉积的平均电功率被限制在40w，相当于火焰释放的4kw热功率的不到1%。这项研究是在一个专门的实验装置上进行的，该装置允许研究应用等离子体放电的火焰动力学。使用扬声器对火焰进行声学扰动，并在中心针电极和注射管边缘之间产生放电。假设等离子体放电不影响CH*发射与放热率波动之间的相关性，用速度和CH*化学发光信号确定火焰传递函数。记录了CH*发射的锁相图像，以评估等离子体对火焰振荡的影响。结果表明，NRP放电对声扰动火焰响应有很强的影响，从而为燃烧控制开辟了有趣的前景。考虑到放电的热效应和化学效应，提出了对火焰传递函数中观察到的变化的解释。然后证明，通过在不稳定条件下施加NRP放电，振荡幅度可以降低一个数量级，从而有效地稳定了系统。ASME版权所有©2013
The effects of Nanosecond Repetitively Pulsed (NRP) plasma discharges on the dynamics of a swirl-stabilized lean premixed flame are investigated experimentally. Voltage pulses of 8-kV amplitude and 10-ns duration are applied at a repetition rate of 30 kHz. The average electric power deposited by the plasma is limited to 40 W, corresponding to less than 1 % of the thermal power of 4 kW released by the flame. The investigation is carried out with a dedicated experimental setup that allows for studies of the flame dynamics with applied plasma discharges. A loudspeaker is used to perturb the flame acoustically, and the discharges are generated between a central pin electrode and the rim of the injection tube. Velocity and CH* chemiluminescence signals are used to determine the flame transfer function assuming that plasma discharges do not affect the correlation between CH* emission and heat release rate fluctuations. Phase-locked images of the CH* emission were recorded to assess the effect of the plasma on the oscillation of the flame. The results show a strong influence of the NRP discharges on the flame response to acoustic perturbations, thus opening interesting perspectives for combustion control. An interpretation of the modifications observed in the transfer function of the flame is proposed by taking into account the thermal and chemical effects of the discharges. It is then demonstrated that by applying NRP discharges at unstable conditions, the oscillation amplitudes can be reduced by an order of magnitude, thus effectively stabilizing the system.Copyright © 2013 by ASME