混合放电臭氧发生器的电场和电子能量分布

Distributions of Electric Field Strength and Electron Energy in Ozone Generation Using Multi-discharge

混合放电是一种非常有前途的臭氧发生形式,为了揭示混合放电臭氧高效发生机理,采用有限元方法数值求解了静电场的Poisson方程,并结合Bolsig+编码求解了电子Boltzmann方程,从而对混合放电高效臭氧发生器进行了电场和电子能量分析。研究结果表明:在无网孔和远离网孔的区域,电场分布比较均匀,而在有网孔存在的区域附近,电场强度表现出剧烈的波动现象;IESDO类型、CESDO类型和CISDO类型这3种类型混合放电臭氧发生器在内放电空间的平均折合电场强度分别为420.5 Td、409.1 Td和731.6 Td,平均电子能量分别为9.946 e V、9.778 e V和15.74 e V;在外放电空间的平均折合电场强度分别为391.3 Td、213.5 Td和184.1 Td,平均电子能量分别为9.497 e V、6.457 e V、5.799 e V;对IESDO类型混合放电臭氧发生器内外放电空间分别进行单独模拟时的电场强度基本与整体模拟一致。由于外放电空间在臭氧产生过程中取决定性作用,因此从电子能量分布角度分析,3种类型混合放电臭氧发生器的优劣排序为IESDO类型>CESDO类型>CISDO类型,与实验结果相符合。另外,性能最好的IESDO类型混合放电臭氧发生器的放电间隙中电场强度并没有因为电极数目的增多而产生叠加现象。

Multi-discharge is one of very promising types of ozone generation. To reveal the mechanism of highly effi- cient ozone generation using multi-discharge, finite element numerical method was employed to solve Poisson＇s equation, and Bolsig＋ code was used to compute electron Boltzmann equation, and in turn to investigate electric field strength dis- tribution and electron energy distribution in discharge gap. The results show that the electric field strength distribution is uniform in non-mesh area and area away from mesh. However, the electric field strength fluctuates intensively near mesh. The average electric field strengths in the internal discharge gap for three types of multi-discharge ozonizer, namely IESDO, CESDO, and CISDO multi-discharge ozonizers, are 420.5 Td, 409.1 Td, and 731.6 Td, respectively. Their aver- ages of reduced electron energy are 9.946 eV, 9.778 eV, and 15.74 eV, respectively. Meanwhile, the average electric field strengths in the external discharge gap are 391.3 Td, 213.5 Td, and 184.1 Td, respectively. Their averages of reduced elec- tron energy are 9.497 eV, 6.457 eV, and 5.799 eV, respectively. The average electric field strength obtained by separate simulation in both internal and external discharge gaps of IESDO multi-discharge ozonizer is little different from that by integral simulation. In terms of the electron energy distribution, IESDO multi-discharge ozonizer achieves the best per- formance followed by CESDO multi-discharge ozonizer, and CISDO multi-discharge ozonizer comes last. The order is consistent with that by experiment results. Additionally, the electric field strength of multi-discharge ozonizer does not overlap each other among different silent discharges because of increasing number of electrodes based on the analysis of the best IESDO multi-discharge ozonizer.