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1.
常压窄间隙介质阻挡放电等离子体辐射特性   总被引:1,自引:0,他引:1  
利用带有透明电极与可测向观察的一个介质阻挡放电(DBD)实验装置对它的常压窄间隙等离子体辐射特性进行了实验研究。结果表明:这一DBD装置的辐射特性会受激励电压、激励频率、DBD结构等多种因素影响。在频率为10~20kHz高压电源激励下,采用窄间隙、薄电介质层结构DBD可以大幅度提高放电空间的电场强度,增加放电功率密度,提高了放电装置性能。  相似文献   

2.
基于介质阻挡放电(DBD)原理,研究设计了一种悬浮电极式的低温等离子体发生设备,产生的等离子体温度较低且对人体安全,可直接接触。用所研制的低温等离子体发生设备对大肠杆菌做了灭活实验,实验结果表明,该设备产生的低温等离子体对大肠杆菌作用10s 以上,在等离子体有效作用区内大肠杆菌杀灭率为100%,表明所研制的低温等离子体发生设备具有很好的杀菌消毒效果。  相似文献   

3.
基于介质阻挡放电(DBD)原理,研究设计了一种悬浮电极式的低温等离子体发生设备,产生的等离子体温度较低且对人体安全,可直接接触。用所研制的低温等离子体发生设备对大肠杆菌做了灭活实验,实验结果表明,该设备产生的低温等离子体对大肠杆菌作用10s 以上,在等离子体有效作用区内大肠杆菌杀灭率为100%,表明所研制的低温等离子体发生设备具有很好的杀菌消毒效果。  相似文献   

4.
Experiments are performed to investigate and compare the characteristics of stable parallel-plate and planar-surface dielectric barrier discharge in helium gas at atmospheric pressure. The evolution of applied electric field profile and the discharge initiation processes are found quite different for both electrode geometries. Further discharge voltage, discharge current, power densities etc. are compared. The differences of basic plasma properties are presented for both the electrode configurations.  相似文献   

5.
通过测量大气压介质阻挡放电等离子体辐射信号,建立偶极子辐射模型,利用快速傅立叶变换,计算了大气压介质阻挡放电等离子体中离子速度分布。计算结果表明,速度分布偏离麦克斯韦分布,并且随着放电过程的进行,离子速度及相对离子数进行有规律的变化。  相似文献   

6.
In this paper, a dielectric barrier discharge operating in nitrogen at atmospheric pressure has been used to improve the surface hydrophilic property of polypropylene (PP) non-woven fabric. The changes in the hydrophilic property of the modified PP samples are investigated by the contact angle measurements and the variation of water contact angle is obtained as a function of the energy density; micrographs of the PP before and after plasma treatment are observed by scanning electron microscopy (SEM) and the chemical composition of the PP surface before and after plasma treatment is also analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the surface hydrophilic property of the PP samples is greatly improved with plasma treatment for a few seconds, as evidenced by the fact that the contact angle of the treated PP samples significantly decreases after plasma treatment. The analysis of SEM shows that the surface roughness of the treated PP samples increases due to bonding and etching in plasma processing. The analyses of FTIR and the C1s peak in the high-resolution XPS indicate that oxygen-containing and nitrogen-containing polar functional groups are introduced into PP surface in plasma processing. It can be concluded that the surface hydrophilic property of the modified PP samples has been obviously improved due to the introduction of oxygen-containing and nitrogen-containing polar groups and the increase of the surface roughness on the PP surface.  相似文献   

7.
通过测量大气压介质阻挡放电等离子体辐射信号,建立偶极子辐射模型,利用快速傅立叶变换,计算了大气压介质阻挡放电等离子体中离子速度分布。计算结果表明,速度分布偏离麦克斯韦分布,并且随着放电过程的进行,离子速度及相对离子数进行有规律的变化。  相似文献   

8.
This paper performs a numerical simulation of concentric-ring discharge structures within the scope of a two-dimensional diffusion--drift model at atmospheric pressure between two parallel circular electrodes covered with thin dielectric layers. With a relative high frequency the discharge structures present different appearances of ring structures within different radii in time due to the evolvement of the filaments. The spontaneous electron density distributions help understanding the formation and development of self-organized discharge structures. During a cycle the electron avalanches are triggered by the electric field strengthened by the feeding voltage and the residual charged particles on the barrier surface deposited in the previous discharges. The accumulation of charges is shown to play a dominant role in the generation and annihilation of the discharge structures. Besides, the rings split and unify to bring and annihilate rings which form a new discharge structure.  相似文献   

9.
分别采用空气、氩气大气压介质阻挡放电(DBD)等离子体对重油进行了处理.对经空气DBD等离子体处理后的重油进行粘温特性分析,发现重油粘度升高,流动性变差.红外光谱和四组分分析结果表明重油的重质组分含量升高,重油胶体体系被破坏,同时生成大量刺激性气味气体.为了便于分析气态产物的成分和含量,采用大气压氩气DBD等离子体处理重油并收集气体产物.气相色谱分析发现生成气中含有大量C1-C5的烃类和一定量氢气,其中氢气和甲烷含量占生成气的70%以上.实验结果表明重油在等离子体作用下既发生裂解又发生聚合反应,既生成低碳烃类,本身的流动性也变差.  相似文献   

10.
The experimental observation of a two-dimensional self-organized square lattice pattern in a planar surface barrier discharge is reported. The discharge was operated near atmospheric pressure in helium gas. The transition from irregular plasma spot pattern to a square lattice pattern is achieved by reducing the discharge driving frequency. On increasing the driving frequency the regular lattice pattern is destroyed and again transforms to an irregular plasma spot pattern. Dielectric degradation and powder formation is also observed after discharge process. Spatio-temporal behavior of observed plasma pattern is presented.  相似文献   

11.
介绍一种结构设计简单、操作运行方便的新型毫米量级大气压冷等离子体射流发生技术.这种射流可以在大气压条件下,利用多种工作气体(如Ar,He,N2),通过毛细管介质阻挡放电(DBD)的方式实现.使用频率为33kHz,峰值电压为1—12kV的双向脉冲电源,利用Ar,He,N2等工作气体,在毛细管内形成了稳定的冷等离子体射流.放电区域的光辐射空间分布利用商用CCD摄像机记录,从中研究放电形态和空间分布,观察到了在DBD区域的流动气体放电和在毛细管出口处形成的等离子体射流 关键词: 冷等离子体射流 毛细管介质阻挡放电 射流射程 射流激发温度  相似文献   

12.
This paper presents surface dielectric barrier discharge plasma generators as an efficient source of low-energy ions. Either positive or negative ions can be extracted from a plasma cloud with an external DC field created by the third electrode. Three different cross-section geometries of DBD generators were analyzed, simulated and fabricated. Currents of ions extracted from the plasma cloud were measured and the results were discussed. It was demonstrated that if the third electrode consists of liquid–gas interface, the presented arrangement can be used as a versatile reactor for nanomaterial synthesis (on the example of the synthesis of silver nanoparticles).  相似文献   

13.
Safety and efficiency are two characteristics that must be satisfied by an electric charge neutralizer. The dielectric barrier discharge (DBD), which has the advantage of preventing arc transition, is an interesting tool to safely neutralize unwanted charge. This paper is aimed at studying the efficiency of neutralizing charged polyethylene (PE) granules by using a dielectric barrier discharge. During this study, several factors were considered such as the amplitude and the frequency of the AC voltage, the polarity and the charging mode of the samples, as well as the electrode configuration. Two DBD electrode configurations were considered: simple DBD and a DBD with installed metallic grid. The obtained results show that using the DBD can lead to excellent neutralization results when the grid is installed. With the appropriate voltage amplitude and frequency and with grid installed, the elimination of nearly 99% of the initial surface charges can be achieved. The metallic grid placed between the DBD electrode and the target enhances significantly the neutralization efficiency.  相似文献   

14.
The dielectric barrier discharge of helium in a 6 mm gap at atmospheric pressure was studied. In this paper, the influence of electric field distribution on the uniformity of DBD is analyzed theoretically and verified by experiments. The experimental results show that the mesh electrode produces a local enhancement effect by affecting the electric field and then produces corona discharge, which provides seed electrons for the subsequent discharge process. The effects of mesh diameter and size on discharge uniformity and stability are analyzed, the electrode structure parameters are optimized, the method of a segmented electrode is proposed, and the discharge process and charge distribution are studied. The electrical diagnosis results of plasma technology show that the segmented mesh electrode reduces the breakdown voltage of DBD and increases the charge deposition.  相似文献   

15.
Dielectric barrier discharge (DBD) of Helium and Helium + air modify the surface of Angora rabbit fibers. DBD treatment carried out at different power densities, changes the morphology and chemical composition of the surface of Angora fiber. Scanning electron microscopy (SEM) results reveal that the DBD treatment eliminates fibrosity from the fiber surface. X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer (FTIR) spectrum confirm the increase in oxygen bonding at the surface. These changes reduce shedding of the fibers and improve dye-uptake property. However, even after 10 min of plasma exposure the thermal insulation (heat keeping ratio) of Angora fibers nearly remain unchanged. It has been noticed that DBD treatment (10 min) reduces whiteness of the fiber.  相似文献   

16.
大气压下多脉冲均匀介质阻挡放电的研究   总被引:15,自引:0,他引:15       下载免费PDF全文
王艳辉  王德真 《物理学报》2005,54(3):1295-1300
基于一维流体力学模型,数值计算研究了大气压下氦气中多脉冲均匀介质阻挡放电的形成原因和性质,分析讨论了所加电压频率、幅值及介质板性质等对多脉冲均匀放电的影响. 模拟结果显示,当放电间隙较小时,由于介质表面积累电荷增加,感应电场增强,在外加电压的每半个周期内,可以形成多个放电脉冲,这些脉冲相应于等时间间隔的分立击穿. 放电间隙越窄,半个周期内形成的脉冲数目越多. 所加电压频率和幅值的变化不仅影响脉冲的幅度,同时也使放电脉冲的数目发生变化,而介质层厚度及介电常数的变化对放电脉冲数目没有明显的影响. 关键词: 大气压均匀放电 介质阻挡放电 数值模拟 等离子体  相似文献   

17.
在同轴圆柱单介质内外双水冷结构的DBD臭氧发生器的放电间隙内分别填充玻璃珠、高铝瓷、石英砂和熔融石英砂等颗粒,研究填充颗粒材料、粒径大小、间隙宽度等参数对臭氧生成效率的影响.结果表明:颗粒材料的介电常数是影响其臭氧制取效果的主要因素,随着介电常数的增加,间隙击穿电压降低,但由于颗粒导致电场的畸变,间隙折合场强增加,臭氧生成的最大能效降低,饱和浓度提升;高铝瓷具有最高的臭氧饱和浓度,与未填充的空床相比,饱和浓度提升136%;对于填充不同粒径熔融石英砂颗粒,随着粒径的增加,间隙击穿电压上升,间隙的折合场强提高,臭氧生成的最大能效降低,而饱和浓度提升;通过在宽间隙内填充介质颗粒可以得到窄间隙宽度的臭氧制取效果.  相似文献   

18.
雷枭  方志  邵涛  章程 《强激光与粒子束》2012,24(05):1206-1210
采用自行研制的低造价、小体积、可产生幅值0~35 kV、重复频率1 kHz的高压s脉冲电源,设计了一套以大气压氖气为工作气体的介质阻挡放电(DBD)等离子体射流源,通过测量并计算放电过程中的电压-电流波形、拍摄放电图像、光谱分析等手段,对电压幅值、气体流速对氖气等离子体射流特性的影响进行了研究。结果表明:s脉冲电源激励下大气压氖气DBD能产生锥状的等离子射流且其等离子强度适中;s脉冲电源电压幅值的快速上升,可在放电空间瞬间施加高的过电压,能有效促进放电功率、电子密度、电子激发温度和射流长度的增加;工作气体流速的增加使得放电功率、电子激发温度和电子密度减小,而射流长度变化很小;一定条件下,能形成长距离的射流。  相似文献   

19.
大气压介质阻挡丝状放电时空演化数值模拟   总被引:2,自引:0,他引:2       下载免费PDF全文
张远涛  王德真  王艳辉 《物理学报》2005,54(10):4808-4815
通过数值求解二维流体方程,在均匀的初始条件下研究了大气压丝状放电的整体时空演化.通过模拟可以发现,在丝状放电的时空演化过程中,各条放电通道在不同位置相继发生击穿,且放电通道有遍历整个放电空间的趋势.在一定条件下,放电通道还会发生分裂与合并现象,其中放电通道的分裂导致了放电空间中放电通道的增加,而放电通道的合并则提供了一条放电空间中放电通道减少的途径.研究还表明,介质表面电荷是影响丝状放电整体时空演化的关键因素之一. 关键词: 介质阻挡放电 丝状放电 数值模拟 时空演化  相似文献   

20.
介质阻挡均匀大气压氮气放电特性研究   总被引:1,自引:0,他引:1       下载免费PDF全文
王艳辉  王德真 《物理学报》2006,55(11):5923-5929
基于一维流体力学模型,对介质阻挡均匀大气压氮气放电特性进行了数值计算研究.模型中考虑了氮气中主要的电离、激发过程,所包含的粒子种类为e,N2,N+2,N+4,N2(a1-u),N2(A3+u).模拟结果显示,氮中的放电具有低气压下汤生放电的特性.放电电流幅度较小,放电过程中气体电压变化缓慢,电子密度远低于离子密度,而且最大值出现在阳极,电子不能在放电间隙中被俘获,不存在中性等离子体区,气体中的电场趋于线性变化.亚稳态N2(A3+u)和N2(a1+u)在整个放电空间都具有非常高的密度,比电子密度高三个量级以上,亚稳态密度的最大值出现在阳极,这样的分布决定了放电的空间结构.放电所需的种子电子主要由亚稳态之间潘宁电离提供,这种机理使放电的电离水平较低,导致氮气中的放电只能是汤生放电.随着放电参数的变化,多电流峰放电也可在氮气中获得. 关键词: 大气压均匀放电 介质阻挡放电 数值模拟 氮气  相似文献   

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