大气压下脉冲DBD臭氧发生放电特性的数值模拟

发布时间：2018-05-17 07:04

本文选题：臭氧发生 + 脉冲介质阻挡放电　；参考：《南昌大学》2017年硕士论文

【摘要】：由于脉冲介质阻挡放电(Dielectric Barrier Discharge,DBD)是将能量在时间尺度上进行压缩,可以在极短时间内产生高功率和高能电子,从而使流光均匀分布,促进流光放电的发展。因此,脉冲DBD成为臭氧发生领域中的一个研究热点。许多学者通过改变电极结构,电压形式等方法,对脉冲DBD进行了深入的研究。虽然在一定程度上提高了臭氧产率,但是由于实验条件的限制,脉冲DBD机理还并不完善。因此,本文对纳秒脉冲DBD臭氧发生建立一维流体动力学仿真模型,模型中考虑了12种粒子和65个化学反应。同时,搭建纳秒脉冲DBD臭氧发生的实验平台,通过对比实验测量和模拟计算得到的电压-电流,验证了模型的正确性。在验证模型正确的基础上,对脉冲DBD臭氧发生的放电特性和能量传递机理开展系统的研究,得到的主要结论如下:1)首先对单次脉冲DBD臭氧发生进行数值模拟,模拟结果发现,一个脉冲电压周期出现两次极性相反的放电,分别位于电压的上升阶段和下降沿阶段。在电流密度上升阶段,折合电场强度和平均电子能量在阴极鞘获得最大值,而电子密度则在鞘层外获得最大值。随着放电的发展,三者的峰值都在不断增加并不断向阴极运动,同时阴极鞘也在不断的变窄。在电流密度下降阶段,阳极附近的折合电场强度和平均电子能量有所上升,放电空间其他位置的折合电场强度、平均电子能量和电子密度都在逐渐减小。另外还发现脉冲DBD一次放电的过程中,输入能量的19.4%被电子吸收,其中41.6%的能量被用于维持产生臭氧反应所需要的能量。2)通过系统地研究脉冲参数对脉冲DBD特性的影响,结果发现电流密度、电晕起始电压和电流密度峰值时刻的电子密度、平均电子能量都随着脉冲电压幅值的升高而不断增加。当脉冲电压上升时间增加时,一次放电的电流密度随之减小,而二次放电的电流密度则随之增加,另外电晕起始电压和电流密度峰值时刻的电子密度、平均电子能量都是随之不断减小。脉宽的变化对一次放电电流密度没有影响,但是二次放电的电流密度则随着脉宽的增加而逐渐降低。
[Abstract]:Since the pulse dielectric barrier discharge (DDBD) compresses energy on a time scale, it can produce high power and high energy electrons in a very short time, thus uniform distribution of streamer and promote the development of streamer discharge. Therefore, pulsed DBD has become a hot spot in ozone generation field. Many scholars have studied pulse DBD deeply by changing electrode structure and voltage form. Although the ozone yield is improved to some extent, the mechanism of pulsed DBD is not perfect due to the limitation of experimental conditions. Therefore, a one-dimensional hydrodynamic simulation model for nanosecond pulsed DBD ozone generation is established, in which 12 kinds of particles and 65 chemical reactions are considered in the model. At the same time, the experimental platform of nanosecond pulse DBD ozone generation is built, and the correctness of the model is verified by comparing the voltage-current obtained by experimental measurement and simulation calculation. Based on the correctness of the model, the discharge characteristics and energy transfer mechanism of pulsed DBD ozone are systematically studied. The main conclusions are as follows: (1) first, numerical simulation of monopulse DBD ozone generation is carried out, and the simulation results show that, Two discharges with opposite polarity occur in a pulse voltage cycle, which are located at the rising and descending stages of the voltage, respectively. At the stage of increasing current density, the maximum value of the reduced electric field intensity and the average electron energy are obtained in the cathode sheath, while the maximum electron density is obtained outside the sheath. With the development of discharge, the peak value of the three is increasing and moving to the cathode, and the cathode sheath is also becoming narrower. At the stage of decreasing current density, the electric field intensity and the average electron energy near the anode increased, while the electric field intensity, the average electron energy and the electron density at other positions in the discharge space decreased gradually. It was also found that 19.4% of the input energy was absorbed by electrons during the primary discharge of pulsed DBD, of which 41.6% of the energy was used to maintain the energy required to produce ozone reaction.) the effects of pulse parameters on the characteristics of pulsed DBD were systematically studied. The results show that the electron density and the average electron energy at the peak moment of current density, corona initial voltage and current density increase with the increase of pulse voltage amplitude. When the rise time of pulse voltage increases, the current density of primary discharge decreases, and the current density of secondary discharge increases. In addition, the electron density at the peak moment of corona initial voltage and current density increases. The average electron energy decreases with it. The change of pulse width has no effect on the current density of primary discharge, but the current density of secondary discharge decreases with the increase of pulse width.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ123.2

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