共查询到20条相似文献,搜索用时 15 毫秒
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介质阻挡放电的放电过程仿真研究 总被引:7,自引:5,他引:7
为深入地理解介质阻挡放电(DBD)的放电机理和实现DBD等离子体的大规模工业应用,采用基于连续性方程和泊松方程的DBD模型仿真研究了大气压空气中DBD的放电过程,计算得到放电空间的电子密度、电场强度和电压电流随时间变化的规律,讨论了阻挡介质在DBD放电不同阶段的作用。仿真结果表明,DBD的微放电过程可分为电子崩、流注和放电熄灭3个连续的阶段。在电子崩和流注阶段间,阻挡介质主要起到加速流注形成的作用;而在放电熄灭阶段,阻挡介质主要起到限制放电电流的自由增长,从而阻止放电发展到电弧的作用。 相似文献
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为了研究SF_6/N_2混合气体电介质击穿现象,利用编写的Matlab程序对放电通道发展过程进行数值模拟,并结合分形几何原理计算放电树枝的分形维数。基于分形理论,建立了考虑空间电荷分布和引入物理时间的棒-板分形放电仿真模型,通过有限元方法(FEM)计算空间电场,并首次结合通量校正传输(FCT)法求解带电粒子连续性方程,研究了不同发展概率指数、不同放电阈值和SF_6含量变化下分形放电特性。结果表明:概率指数越大,SF_6含量越高,则分形维数越小,放电树枝分叉也越少;体积含量50%/50%的SF_6/N_2混合气体放电分形维数D=1.219 2,整个放电过程流注发展平均速度为1.15Mm/s,并得到了不同时刻空间电荷及轴向电场与电子浓度的分布。 相似文献
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Bunni N.N. McGrath P.B. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1996,3(1):136-143
A simulation study of streamer growth within a dielectric liquid at a solid interface was undertaken. Using the finite element method with computer graphics, the shape of the growing streamer was determined and plotted. In addition, the changing voltage and electric field values within the dielectric were calculated, and simulated images of these parameters produced. The behavior of the streamer is based on the formation of a localized gas phase discharge and the growth of the resulting plasma within the liquid. The model determines an inception site and predicts a growth path that depends on the electric field immediately surrounding the streamer tip. Two liquids, n-hexane and water, both with an interface, were investigated using the simulation model. The effect of the choice of the liquid and the solid dielectric, in addition to the geometry, was explored. For mixed solid and liquid insulation, the results show that streamer growth depends on the permittivity mismatch between the two materials. Experimental findings are presented that show streamer growth for different interfacial conditions. A good correlation is observed between the theoretical and experimental work 相似文献
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Pompili M. Mazzetti C. Bartnikas R. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2000,7(1):113-117
Partial discharge pulse phase analysis carried out on a mineral oil and a perfluoropolyether with point-to-plane electrodes provided further and additional evidence that discharge epochs tend to be concentrated in the vicinity of the alternating voltage peaks at discharge inception in lieu of the voltage zeros characteristic of normal cavities occluded in solid and liquid-impregnated solid insulating systems. Relatively large positive polarity discharge pulses, having an associated charge transfer of ⩾15 pC with a recurrence rate of at least one per every ten consecutive cycles, appear initially on the positive half-cycle; with further increases in applied voltage both their number and magnitude continue to exceed those of negative polarity over the negative half-cycle. This behavior is to be distinguished from that commonly observed with high sensitivity measurements, which clearly indicate that early discharge onset in liquids is characterized by the occurrence of minute highly intermittent negative polarity pulses. The increase in charge transfer of the discharge pulses with applied voltage is suggestive of the development of longer more intense streamers in the dielectric liquids at the more elevated electrical fields. Also the results infer that discharges or streamers form and propagate more readily in the mineral oil than in the electronegative perfluoropolyether 相似文献
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Lisitsyn I.V. Inoue H. Katsuki S. Akiyama H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1999,6(1):105-108
An inductive energy storage switch system for the destruction of solid materials is reported. This is based on creating a pulsed electric breakdown in the solid dielectric, which then propagates in the specimen. This scheme provides a higher destruction effectiveness compared to a capacitive energy storage system. The higher energy efficiency is attributed to a different discharge behavior during the discharge build-up in the solid material. A higher applied voltage causes a breakdown of a larger number of voids in a heterogeneous solid dielectric. The energy transfer to partial discharges, when using the inductive storage system, is faster than for the capacitive energy storage system, due to a shorter risetime of the discharge current 相似文献
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Wanou M. Kimura M. Nakajima J. Matsuda T. 《Industry Applications, IEEE Transactions on》1989,25(3):547-551
A dielectric surface is charged without a corona discharge using a conductive fur brush to which an electrical potential of several hundred volts is applied. The fur brush, which consists of 10-μm-thick conductive fiber, lightly touches the surface of the (Mylar film or photoreceptor) dielectric. It is clear that brush charging is accomplished by direct charge transfer, gas discharge, and triboelectric charging. The direct charge transfer, which is the primary charging process, is analyzed using an ohmic contact model. The charge potential is nearly proportional to that of the brush. When the charging time is longer than 0.3 s, the charged potential on the surface photoreceptor saturates at almost that of the brush, the difference being less than 50 V. This is about the same as in corona charging. Brush charging is, therefore, useful as a low-voltage charging technique 相似文献
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空气中介质阻挡大气压辉光放电特性的研究 总被引:3,自引:0,他引:3
采用筛网电极和聚对苯二甲酸乙二醇脂(PET)薄膜作为阻挡介质的介质阻挡放电(DBD)结构在空气中产生大气压辉光放电(APGD)。通过测量空气中APGD的电气特性和发光强度空间的分布特性,比较了它们与丝状DBD的区别: 通过研究APGD的放电特性,分析了空气中APGD的放电机理。实验结果与分析表明,采用该电极结构可以在空气中产生APGD,空气中APGD的放电特性与丝状DBD具有明显的区别,筛网电极起到了在气隙击穿前产生电晕放电对驻极体阻挡介质充电的作用。 相似文献
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气体放电对金属平板强化传热作用的研究 总被引:2,自引:0,他引:2
文中对比研究了电晕、介质阻挡以及辉光放电对空气-金属之间对流传热系数的影响作用。通过对加热器功率以及铜板电极温度测量,计算获得在自然对流以及电极间发生放电两种情况下对流传热系数。在气体放电强化传热的作用下对流传热系数获得数倍的增加。在直流电晕放电实验中,当均匀的直流辉光放电产生时,空气-金属之间传热速率获得最大幅度的提高。采用介质阻挡放电在提高空气-金属之间传热速率的同时,放电间隙击穿电压发生显著提高,也使放电在实际应用中更易于控制。 相似文献
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Pompili M. Mazzetti C. Bartnikas R. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1998,5(3):402-407
Simultaneous narrow band (300 kHz) and wide band (500 MHz) measurements were carried out to obtain estimates of the apparent charge transfer associated with discrete isolated discharge pulses and discharge pulse bursts, which are observed to occur in dielectric liquids when wide band detection systems are utilized. The integrated apparent charge transfers determined with the narrow band system ranged from 12 to 95 pC, which represents typically the lower range of values normally encountered with PD activity in dielectric liquid-filled or impregnated equipment. While the discharge phenomena in perfluoro polyether liquids was found to be typified by sporadic appearances of single isolated pulses involving charge transfers between 33 and 38 pC, the discharge events in mineral oils assumed most frequently the form of pulse bursts, displaying the usual pulse sequences of quasi-ascending amplitudes; the overall integrated apparent charge transfer of the observed pulse bursts extended commonly from 12 to 16 pC. The charge release, occurring with the first (initiating) smallest discharge pulse within the pulse bursts, was estimated to be of the order of ~1 pC 相似文献
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Kacprzyk R. Ulatowski W. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(3):655-660
Results of investigation of a double layer dielectric system applied for pressure distribution determination is discussed in the paper. The system consists of elastic and rigid solid dielectric layers. The trybo-charge is generated on the contact between the rough surface of the elastic and dielectric layers when the system is subjected to an external stress. It was shown that the local effective surface charge density on the rigid dielectric layer depends on the local pressure value. The generated charge produces a proportional voltage across the solid dielectric layer after removing the elastic one (foam). This way, the pressure may be converted into a voltage signal, which is ?memorised? by a solid dielectric layer. Finally, the ?pressure map? converted into ?an electric potential map? can be visualised by potential distribution determination. The potential distributions obtained in the system for different cases of non-uniform pressure distributions and different elastic layers are presented in the paper. 相似文献
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Prarthan D. Mehta S. B. Chakrabarty 《International Journal of Numerical Modelling》2013,26(2):127-139
This paper presents a method for the evaluation of capacitance and charge distribution of a dielectric coated metallic disk and a dielectric coated metallic hollow truncated cone with top and bottom cover plates using the method of moments (MoM) based on pulse basis function and point matching. Boundary conditions for the potential on the conductor surfaces and continuity of the normal component of the displacement density at the dielectric‐free space interface is used to generate two integral equations. Two sets of simultaneous equations are formed from the two integral equations by using MoM. The total free charge on the conductor surface is found from the solution for the set of simultaneous equations. The validity of the analysis has been justified by comparing the data on capacitance available in the literature for metallic disk and hollow truncated cone with top and bottom cover plates, with the data on the capacitance, computed by the presented method for similar structures considering very low dielectric constant as well as very thin dielectric coating. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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发展了一个用于固体氧化物燃料电池的三维数学模型,模型同时考虑了流体流动、热量传递、电荷传递、多组分传递和电化学动力学.研究的区域包括阳极和阴极的流道、扩散层和催化层,以及中间的电解质层在内的整个电池.采用统一的数学方程描述整个区域的传递现象,而用不同的源项和相应的物性参数反映不同性质的层.通过计算流体动力学(CFD)技术求解传递方程组,并耦合电化学动力学方程,获得了电池内的流动、温度、压力、反应物组分浓度等分布,并将模拟得到的极化性能与文献中的实验数据进行了比较,结果表明两者符合得较好. 相似文献
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Zhang S. Morcos M.M. Anis H. Gubanski S.M. Srivastava K.D. 《Power Delivery, IEEE Transactions on》2002,17(2):318-325
Coating the inside surface of gas insulated switchgear (GIS) enclosures with a dielectric film reduces the deleterious effect of electrode surface roughness, impedes the development of metallic particle initiated microdischarges, increases the field required to lift particles, and reduces the charge acquired by particles, all of which help alleviate the adverse effect of contaminating metallic particles on insulation withstand. The performance of particle-contaminated compressed gas systems with dielectric coated electrodes is analyzed. Two mechanisms for the transfer of charge from electrodes to contaminating particles are considered, namely, conduction through the coating layer and microdischarges in the surrounding gas. The paper presents an electrostatic study of the particle lifting fields with dielectric covered electrodes. The overall breakdown strength of the system is evaluated and the results are discussed in the light of experimental findings 相似文献
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高压脉冲放电水处理技术的理论研究 总被引:6,自引:3,他引:3
为了探讨高压脉冲放电水处理技术的机理及模型,归纳、概括了高压脉冲放电过程中物理效应的形成及其作用、液体介质的击穿机理及击穿模型,还分析了高压脉冲放电过程中发生的化学过程。所得结论为:弧光放电发射的光辐射最强,火花放电次之,流光放电较弱;紫外辐射可把臭氧和过氧化氢分解为氧化性更强的羟基;冲击波可间接引起热解和自由基反应;液体介质的击穿主要可分为电击穿理论、热力(气泡)击穿理论,建立的模型在一定的范围内能准确地预言实验结果;气、液界面发生苯酚降解的化学反应是羟基进攻和臭氧氧化,氧气和氩气导致形成不同的降解副产品,而溶液中的化学过程则主要是羟基进攻。 相似文献