Ar/H_2O大气压等离子体射流放电特性

Discharge characteristics of Ar/H_2O atmosphere pressure plasma jet

为了研究水蒸气体积分数对大气压等离子体射流放电机理及放电效率的影响，进而产生高活性低温等离子体并优化其效率。通过对大气压氩水等离子体射流的电压电流波形和Lissajous图形等电气特性的测量及发射光谱和发光图像等光学特性诊断，研究了不同水蒸气体积分数时，等离子体射流的放电特性。通过计算放电功率、传输电荷量、电子激发温度、分子振动温度和分子转动温度等主要放电参量，研究了它们随水蒸气体积分数的变化趋势，并结合放电机理对所得实验结果进行分析。结果表明，Ar／H2O等离子体射流除了产生N2和Ar。还有OH和O，气体温度在525～720K之间变化，为典型的低温等离子体；随着水蒸气体积分数的增加，等离子体习习喷出管口的长度减小，放电功率减小，发光强度减弱，转动温度和振动温度增加；相同功率下，水蒸气体积分数为0．5％时，产生的OH达到最大。

The influences of water vapor concentration on discharge mechanisms and discharge efficiency of atmosphere pressure plasma jet （APPJ） are studied to generate highly active cold plasma and optimize its efficiency. The discharge character- istics of APPJ with different water vapor content are studied by means of electrical measurements on voltage and current wave- forms and Lissajous figures, and the optical properties are diagnosed using optical emission spectra and light-emission pictures. The main discharge parameters, such as discharge power, transported charges, electronic excitation temperature, molecular vi- brational temperature and molecular rotational temperature are calculated, and the changing tendencies of them with applied volt- age are studied, with the experimental results being explained by analyzing the discharge mechanism. The results show that the APPJ in Ar/H20 produces Nz, At, O, and OH. Gas temperature changes between 525 K and 720 K, which shows that the AP- PJ in Ar/H20 plasma is a typical non-thermal one. With the increase of water vapor concentration, the plasma plume, light in- tensity and discharge power decrease, and the rotational temperature and vibrational temperature increase. Under certain dis- charge power, the content of OH produced reaches maximum when the water vapor content is 0.5%. Accordingly, better results can be achieved under this condition for application in surface modificaicion of polymer materials.