轴对称等离子体射流的实验研究

Experimental Study on the Axial Symmetry Plasma Jets

等离子体射流具有广泛的应用前景。建立了轴对称等离子体射流的模型,显示层流状态下等离子体射流的长度与流量成正比。采用Ne、He、Ar在大气压下用介质阻挡放电的手段得到了等离子体射流,发现层流状态下等离子体射流长度与模型结论一致;但是随着激励电压的升高和气体流量的增大,等离子体射流会发生从辉光放电到丝状放电、从层流到湍流的转捩,射流长度会先增大后减小;工作气体的不同对等离子体射流的性质也有重要影响。

The potential application of atmospheric pressure plasma jets has attracted extensive interests recently. The mathematical model of axial symmetry plasma jets has been established, and it shows that the length of plasma jets is directly proportional to the flow rate when the plasma jets are in laminar mode. Effects of supplying voltage, gas flow rate, internal diameter of the quartz tube and different kinds of working gas （ helium, neon and argon） on the atmospheric pressure dielectric barrier discharge plasma jets have been investigated in the experi- ment. It is found that the length of plasma jets is identical to the result of the mathematical model when the jets are in laminar mode. However, the transitions from glow discharges to filamentary discharges and from the laminar mode to the turbulent mode have also been observed when the supplying voltage/flow rate increased, both of which have lead to the decrease of the plasma jets＇length. The composition of the working gas also has important effect on the transitions.