棒-环电极大气压等离子体射流的光谱特性

通过设计新型的交流电压激励的氩气等离子体射流,在棒电极的上游与下游区域均产生了大气压非平衡态等离子体羽。该射流与平行场射流和交叉场射流不同,它的电场与气流方向的夹角可以在一定范围内变化。结果表明,随着外加电压或夹角的增加,上游羽的长度增加而下游羽的长度减小。利用光学和电学的方法,研究发现随着外加电压的增加,上下游放电脉冲的个数均增加。利用放电的光学发射谱,发现上游羽有Ar和OH的谱线,而下游羽除了Ar和OH的谱线外,还可以观察到N2的谱线。并且下游羽的谱线强度比上游羽的略高。基于碰撞辐射模型,通过谱线强度比的方法研究了上下游羽的电子密度和电子激发温度。结果表明上下游羽的电子密度随着外加电压的增加而增加。上下游羽的电子激发温度也随着外加电压的增加而增加。并且,在同一外加电压时下游羽的电子密度和电子激发温度均比上游羽的高。此外,利用OH发射光谱研究了上下游羽的气体温度,发现下游羽的气体温度也比上游羽的略高。

Spectroscopic Characteristics of Atmospheric Pressure Plasma Plume in a Rod-Ring Electrode Geometry

A novel argon plasma jet driven by an alternating current voltage is developed to generate atmospheric pressure non-equilibrium plasma plumes in the upstream and downstream regions of the rod electrode.The novel jet is neither similar to a linear-field jet,nor a cross-field jet.The angle between the electric field and the gas flow direction can be changed easily in this novel jet.By increasing the applied voltage or the angle,the upstream plume length increases and the downstream plume length decreases.With optical and electrical methods,the discharge aspects are investigated and it is found that the discharge pulse number increases with increasing the applied voltage for every voltage cycle.With optical emission spectroscopy,it is found that the spectral lines of Ar and OH can be observed in both of the upstream and downstream plumes.Besides,the spectral lines of N2 can be only observed in the downstream plume.Moreover,the spectral intensity of the downstream plume is slightly higher than that of the upstream plume.Based on the collision-radiation model,the intensity ratio of two spectral lines is investigated to obtain the electron density and the excited electron temperature for the upstream and downstream plumes.Results indicate that the electron densities increase with increasing the applied voltage for the upstream and downstream plumes.The excited electron temperatures of the two plumes also increase with increasing the applied voltage.Moreover,the electron density and the excited electron temperature of the downstream plume are higher than those of the upstream plume under the same applied voltage.Additionally,the gas temperature is also investigated by fitting the spectra of OH radicals for the upstream and downstream plumes.It is also found that the gas temperature of the downstream plume is slightly higher than that of the upstream plume.