氩气等离子体射流特性:电压、气流、外磁场的综合影响

Characteristics of argon discharge plasma jet:comprehensive effects of discharge voltage,gas flow rate,and external magnetic field

大气压等离子体射流具有广阔的应用前景,而电压、气体流速、外磁场均会影响其性能,其综合影响更会使得放电规律复杂化.但是目前缺乏三者组合对射流特性的综合影响研究,无法更全面评估多放电条件下的放电特性规律.因此,本文以交流氩气等离子体射流为对象,研究了电压、外磁场、气体流速三者组合作用对放电的宏观形貌、功率、气体温度、电子激发温度、电子密度、Ar*光谱强度、·OH粒子数密度等参量的影响.结果表明,电压对射流参量的影响规律不受气体流速和外磁场的影响,增大电压能提升放电性能;加入外磁场可以在不引起放电功率显著变化的情况下提升放电性能,尤其是当磁场仅作用于等离子羽时,提升效果最显著;气体流速对射流性能的改变会受到电压和外磁场的影响,并不是在单个放电条件最优的组合情况下取得最佳的射流性能.本研究有助于更全面了解不同放电条件下射流特性,为优化射流性能提供指导,有利于推动大气压等离子体射流技术的发展.

Atmospheric pressure plasma jet has received widespread attention due to its enormous potential applications in various fields,and its discharge conditions play a key role in changing their physical and chemical properties and ultimately determining its application effectiveness.Factors such as discharge voltage,gas flow rate,and the introduction of an external magnetic field intricately influence the performance of plasma jet.The combined effects of any two of these factors can yield enhanced outcomes,while also bringing complexity to the discharge phenomenon.However,there is currently a lack of research on the combined effects of external magnetic field,discharge voltage,and gas flow rate on the characteristics of plasma jets,making it difficult to comprehensively evaluate the discharge characteristics of plasma jet under multiple discharge conditions.Therefore,this paper focuses on an AC excited atmospheric pressure argon plasma jet and investigates the combined effects of external magnetic field,discharge voltage,and gas flow rate on various characteristic parameters of the plasma jet,including macroscopic morphology,discharge power,gas temperature T_(g),electron excitation temperature T_(exc),electron density n_(e),emission intensity of excited state Ar*particles,and number density of ground state·OH particles by using methods of camera shooting,and electrical parameter measurement,spectroscopic analysis of emission and absorption spectra.The obtained results are shown below.The effect of discharge voltage on the characteristic parameters of the plasma jet is not affected by gas flow rate or the existence of an external magnetic field.The increase of discharge voltage can improve jet performance by enhancing the discharge power,extending the plasma plume length,elevating the gas temperature T_(g)and electron excitation temperature T_(exc),increasing the electron density n_(e)and emission intensity of excited state Ar*particles,as well as the number density of ground state·OH particles.The addition of an external magnetic field can improve the jet performance without significantly changing the discharge power,and the extent of this improvement is influenced by the mode of magnetic field action.Notably,the enhancement of jet performance is most significant when the magnetic field selectively targets the plasma plume,excluding direct interaction with electrode discharge region.The effect of gas flow rate on jet performance becomes intricate:it is intertwined with the effect of voltage and the effect of external magnetic field.When an external magnetic field is present,excessive voltage and gas flow rate may reduce the number density of ground state·OH particles generated by plasma jet.This underscores the need for a detailed understanding when optimizing jet performance under various discharge conditions.Simply combining the optimal conditions for each individual factor does not guarantee the achievement of peak jet performance when all three discharge conditions work synergistically.This study presents valuable insights into the discharge characteristics of plasma jet under different discharge conditions,providing guidance for optimizing the performance of plasma jet and promoting the advancement of atmospheric pressure plasma jet technology in different application fields.