电工技术学报2025，Vol.40Issue(21)：6819-6831,13.DOI:10.19595/j.cnki.1000-6753.tces.250147
0.5%掺氨氩气脉冲介质阻挡放电特性的实验与仿真研究
Experimental and Simulation Research of Nanosecond Pulse Dielectric Barrier Discharge Characteristics Doped 0.5%NH3 in Argon
摘要
Abstract
Plasma technology,characterized by low operational temperatures and broad electron energy distribution,has emerged as a promising approach for hydrogen production through ammonia decomposition.Pulse voltage has the characteristics of steep rising/falling edges and narrow pulse width.The fast voltage change rate enhances the excitation and ionization processes and has significant superiority in improving discharge uniformity and increasing particle abundance.Precise regulation of pulsed voltage-driven plasma parameters is crucial for optimizing hydrogen generation efficiency. In this paper,under normal temperature and pressure,square wave pulse voltage is used to drive the Ar-NH3 dielectric barrier discharge(DBD)structure to generate uniform Ar-NH3 discharge plasma.The barrier dielectric is quartz with εr=3.7.The diameters of the barrier dielectric are both 40 mm,the thickness is d1=d2=1 mm,and the air gap distance is dg=4 mm.The proportion of NH3 in the mixed gas is 0.5%,and the total pressure is maintained at 100 kPa.The discharge drive voltage is a pulse waveform(tr=tf=100 ns,tw=1 000 ns,f=20 kHz).The voltage and current signals,discharge evolution behavior and emission spectra of Ar-NH3 discharge plasma were tested and analyzed.To further explain the experimental results,a one-dimensional fluid simulation model was established,whose parameters were kept consistent with the experimental data.The discharge characteristics and product distribution characteristics of the Ar-NH3 DBD plasma are systematically analyzed. The results reveal that the development process of discharge mainly includes three stages:rising edge-flat top period-falling edge.During the rising stage of the applied voltage,the air gap voltage ug increases rapidly with the increase of the applied voltage.The negative particles(mainly electrons)in the gas gap move towards the high-voltage side under the action of the electric field,and the positive ions produced by the reaction move towards the ground side.When ug reaches the gas breakdown threshold,discharge occurs,and the positive current pulse reaches its peak.The applied electric field dominates the ionization process in the gap at this time.As the discharge proceeds,negative charges(mainly ions)and positive ions continuously accumulate on the surface of the dielectrics and form stable surface charges.The self-built electric field significantly increases,resulting in a rapid decrease in the net electric field in the gap.The voltage amplitude during the pulse flat-top period remains unchanged,equivalent to a DC voltage.Due to the capacitive property of the DBD device,the gap voltage drops to zero,and the discharge remains in an extinguished state all the time.When the applied voltage pulse enters the descending stage,the applied electric field rapidly decreases.Electrons rapidly migrate to the surface of the dielectric on the grounding side and neutralize the originally accumulated positive surface charges.It rapidly weakens the positive surface charge density σ2,showing a steeper curve descending edge.Meanwhile,positive ions in the gap slowly migrate to the surface of the dielectric on the high-voltage side and neutralize the accumulated negative surface charges.This causes the negative surface charge density σ1 to decrease slowly,showing more gentle curve descending edge.It results in the net electric field in the gap being mainly self-built and significantly enhanced,leading to the occurrence of negative discharge and the appearance of a negative discharge peak.The discharge exhibits characteristic of glow discharge behavior with peak electron density and reduced electric field occurring near the cathode sheath region during the initial high-voltage plateau.Spectral analysis identifies dominant species including Ar* excimers,NH3+ions,and neutral NH and NH2 radicals.Reaction pathway analysis through time-integrated rate coefficients quantifies hydrogen production routes.Primary H2 generation pathways are R7(NH3+e→NH+H2),R8(NH2+NH2→N2H2+H2)and R9(NH+H→N+H2).Mechanistic insights demonstrate that electron density accumulation during voltage rising phases originates from initial electron energy accumulation,collisional excitation via metastable Ar atoms and secondary electron emission enhanced by cathode sheath acceleration.These cumulative effects promote intensive excitation/ionization processes,generating substantial NH,NH2 and H intermediates.Subsequent accumulation of these species during voltage plateau facilitates sustained R8 and R9 reactions,resulting in predominant H2 production near the cathode sheath region.The research results provide guidance for optimizing the hydrogen production effect and determining the optimal parameters.关键词
脉冲介质阻挡放电/氨气制氢/放电特性/放电产物Key words
Pulse dielectric barrier discharge/hydrogen generation from ammonia/discharge characteristics/discharge products分类
动力与电气工程引用本文复制引用
赵妮,田浩,王婧,付强,常正实..0.5%掺氨氩气脉冲介质阻挡放电特性的实验与仿真研究[J].电工技术学报,2025,40(21):6819-6831,13.基金项目
国家自然科学基金资助项目(52307187). （52307187）
