微隙介质阻挡放电装置中的空气均匀放电光谱特性

摘要

The plasmas generated by dielectric barrier discharge in atmospheric pressure air have wide application prospect in in‐dustry .In order to study generation condition and mechanism ,the dielectric barrier uniform discharge in atmospheric pressure air has been studied experimentally with a micro‐gap discharge device .Results of electrical characteristics indicate that it exist several current pulses with short width in half period of the applied voltage at a low voltage ,a large number of micro‐discharge filaments are observed .The discharge power increases with increasing peak value of applied voltage ,the micro‐discharge fila‐ments increase meanwhile .When the peak of applied voltage reaches to 9.2 kV ,only a discharge hump with a width of about 5.5μs appears in a half period of the applied voltage ,micro‐discharge filaments cannot be discerned .The uniform discharge has been obtained finally as the micro‐discharge filaments extend and superimpose randomly .The emission spectrum of dielectric barrier discharge scanning from 330 to 420 nm is collected .It is found that the intensity of 337.1 nm is stronger than that of 391.4 nm . If the intensity of 337.1 nm is considered as the datum reference ,the intensity of 391.4 nm shows the magnitude of electron av‐erage energy .The molecule internal energy is evaluated by vibration temperature .The electron average energy and molecule in‐ternal energy have been investigated by optical emission spectra .It is found that both of them decrease with increasing the ap‐plied voltage .Results indicate that it is not easy to form filamentary discharge when the electrical energy is lower .The average electron energy of uniform discharge is lower than that of the filamentary discharge .These results are of great significance to the application of dielectric barrier uniform discharge obtained in air at atmospheric pressure .%大气压空气中介质阻挡均匀放电产生的等离子体在工业领域具有广阔的应用前景，为研究其产生条件及机理，利用微间隙介质阻挡放电装置，在大气压空气中实现了均匀放电。电学实验结果表明，低电压时电流波形在电压每半个周期存在若干个脉冲宽度很小的脉冲，肉眼观察到大量的微放电丝，随着外加电压增加，放电功率逐渐增加，放电空间内微放细丝增多。当电压增大到9.2 kV时，电流波形在电压每半个周期只存在一个宽度较大（约5.5μs）强度较强的脉冲，观察不到微放电丝，微放电最终扩展叠加形成均匀放电。采集了光谱范围为330～420 nm的发射光谱，氮分子第二正带系337.1 nm的谱线强度明显比氮分子离子第一负带系391.4 nm的强。将337.1 nm谱线的强度归一，391.4 nm谱线的强度即反应了电子平均能量的大小，同时拟合计算了反映分子内部能量的氮分子振动温度。结果表明电子平均能量和分子内部能量都随外加电压的增加而降低。表明放电空间电场能量较低时不容易形成丝状放电，均匀放电模式中电子平均能量比微放电丝放电模式中的低。这些结果对于空气中介质阻挡均匀放电在工业应用方面具有一定的指导意义。