通过二维流体模型,研究介质管的介电常数对大气压氩气冷等离子体射流放电性质的影响.结果表明,射流在介质管内外具有不同的放电性质.当射流在介质管内时,电离波沿着介质管内表面向管口传播,因而呈现环状结构,其传播速度先增加后减小.介电常数越大,环形结构的半径越小,电子密度越低,射流传播的速度也越小.当射流喷出管口后,射流的传播速度迅速提升,然后减小,介电常数越大,提升越快.随着射流的传播,环状结构不断收缩,最终消失.研究结果对大气压冷等离子体源的设计和优化具有一定的理论指导意义.
The effect of dielectric constant of tube on characteristics of atmospheric pressure Ar cold plasma jets has been investigated by using two-dimensional fluid model. It is shown that there are different features of plasma jets in and out of the tube. In the dielectric tube, the ionization wave accelerates firstly and then decelerates as it is propagating along with the dielectric surface, giving rise to the ring structure. The larger the dielectric constant, the smaller jet radius of the ring structure, the lower the electron density, and the smaller jet propagation velocity. When the plasma jet leaves the dielectric tube, its velocity increases dramatically and then slows down. The larger the dielectric constant is, the larger the acceleration is. The ring structure shrinks all the time and vanishes eventually in the jet propagating process. These results provide certain guiding significance for design and optimization of cold plasma sources.
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