Thermal and nonthermal regimes of gliding arc discharge in air flow
Thermal and nonthermal regimes of gliding arc discharge in air flow
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DOI：
10.1063/1.372071
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发表时间：
2000-02-15
影响因子：
3.2
通讯作者：
Kennedy, LA
中科院分区：
文献类型：
--
作者：
Mutaf-Yardimci, O;Saveliev, AV;Kennedy, LA
包含平衡和非平衡等离子体条件的滑动放电为化学过程提供了高能量效率和选择性。应充分理解和表征在相对高功率水平下满足非平衡等离子体条件的主要参数。在目前的工作中，在广泛的气体速度和功率水平下，对气流中的发散电极之间形成的滑动放电进行了实验研究。根据系统参数，观察到以下放电方式：低功率非平衡放电；热准平衡放电；以及平衡到非平衡转变的滑动放电。分析了系统参数对放电特性的影响。通过实验观察电压增加率随放电长度增长的变化，从而观察到平衡到非平衡的转变。局部电场（定义为 dV/dl）增加了三倍，表明等离子体条件发生了变化。然而，之前报道的长度爆炸现象并没有得到我们的实验数据的支持。平衡相和非平衡相的共存也在现象学理论的框架中进行了讨论，假设在滑动放电通道内形成不断增长的非平衡碎片。研究发现，高流速提供强烈的冷却、电场的增加和气体温度的降低，促进高功率水平下的平衡到非平衡的转变。 (C) 2000 年美国物理研究所。 [S0021-8979(00)05304-4]。
Gliding discharges comprising both equilibrium and nonequilibrium plasma conditions offer high energy efficiency and selectivity for chemical processes. Prevailing parameters satisfying nonequilibrium plasma conditions at relatively high power levels should be well understood and characterized. In the present work, gliding discharges formed between diverging electrodes in air flow were studied experimentally over a wide range of gas velocities and power levels. Depending on the system parameters the following discharge regimes were observed: low power nonequilibrium discharge; thermal quasiequilibrium discharge; and gliding discharge with equilibrium to nonequilibrium transition. The effect of system parameters on discharge characteristics is analyzed. The equilibrium to nonequilibrium transition was experimentally observed as a change of voltage increase rate with discharge length growth. The local electric field, defined as dV/dl, increased up to three times, indicating the change of plasma conditions. However, previously reported phenomenon of length explosion was not supported by our experimental data. The co-existence of equilibrium and nonequilibrium phases is also discussed in the frame of phenomenological theory, assuming formation of a growing nonequilibrium fragment inside the gliding discharge channel. It was found that high flow velocities provide intensive cooling, an increase of electric field, and a decrease of gas temperature, promoting equilibrium to nonequilibrium transition at high power levels. (C) 2000 American Institute of Physics. [S0021-8979(00)05304-4].