On the refinement of the theoretical model for a high-voltage spiral generator

The principle of operation of high-voltage pulse generators proposed by Fitch and Howell and independently by Belkin and Zharkova (1961) is analyzed. It is shown that the Fitch-Howell spiral generator is a particular case of the Belkin-Zharkova transformer. Models are suggested making it possible to describe the performance capabilities of the spiral generator for the case of nonideal geometry and operating conditions. A radically modified Ruhl-Herziger model improving the calculation accuracy by several times is presented. Comparison between calculation results and experimental data shows that the spiral generator is best described by the Tesla coil model when the number of turns is small and the inductance of the switch is high or by the modified Ruhl-Herziger model when the number of turns is large and the inductance of the switch is low.     

基于螺旋线的紧凑型高压纳秒脉冲发生器

提出了一种结合高耦合Tesla变压器和螺旋形成线(FL)的紧凑型高压纳秒脉冲发生器,由内置Tesla变压器充电的螺旋FL包含外屏蔽筒、螺旋中筒和内导体筒,内外筒的两端均短路连接,螺旋中筒的一端开路,另一端穿过内外筒短路端面并与主开关电极连接。该结构简单紧凑、易于实现,输出脉冲前沿快、平顶好。给出了一组10 GW功率、百ns脉宽的FL设计,采用Midel 7131合成酯绝缘介质,FL外筒内径0.88 m,长度2 m。     

基于螺旋线的紧凑型高压纳秒脉冲发生器

提出了一种结合高耦合Tesla变压器和螺旋形成线(FL)的紧凑型高压纳秒脉冲发生器,由内置Tesla变压器充电的螺旋FL包含外屏蔽筒、螺旋中筒和内导体筒,内外筒的两端均短路连接,螺旋中筒的一端开路,另一端穿过内外筒短路端面并与主开关电极连接。该结构简单紧凑、易于实现,输出脉冲前沿快、平顶好。给出了一组10 GW功率、百ns脉宽的FL设计,采用Midel 7131合成酯绝缘介质,FL外筒内径0.88 m,长度2 m。     

多路高电压纳秒矩形波脉冲发生器的研制

为满足脉冲功率实验中对多路高电压纳秒矩形波激励的需求,研制了一台21路高电压纳秒矩形波发生器。此发生器由一个单路高电压纳秒矩形波脉冲发生器和一个21路分路器组成。其中单路高电压纳秒矩形波脉冲发生器可输出幅值约1.07 kV、半高宽约10 ns、上升沿约1.45 ns的矩形波脉冲。利用21路分路器可将该矩形波脉冲分为21路矩形波脉冲,测得每路脉冲幅值可达51 V,半高宽约为10 ns,上升沿约为2.25 ns。     

多路高电压纳秒矩形波脉冲发生器的研制

为满足脉冲功率实验中对多路高电压纳秒矩形波激励的需求,研制了一台21路高电压纳秒矩形波发生器。此发生器由一个单路高电压纳秒矩形波脉冲发生器和一个21路分路器组成。其中单路高电压纳秒矩形波脉冲发生器可输出幅值约1.07kV、半高宽约10ns、上升沿约1.45ns的矩形波脉冲。利用21路分路器可将该矩形波脉冲分为21路矩形波脉冲,测得每路脉冲幅值可达51V,半高宽约为10ns,上升沿约为2.25ns。     

500 kV亚纳秒脉冲X光机研制

高能量亚纳秒脉冲X射线可用于精确定标辐射探测系统的时间响应特性和探测灵敏度,对于脉冲辐射场诊断技术研究具有重要意义。研制了一种小型化、可移动的亚纳秒脉冲X射线源,装置占地区域尺寸为1.2 m×40 cm,重142 kg。设计了双锥形绕组同轴结构变压器,采用新颖的三谐振变压技术,将纳秒脉冲形成线充电至520 kV,通过油介质自击穿开关放电,输出370 kV,3.8 ns的高压脉冲。设计了多级过匹配传输线提升输出电压,并利用油介质peaking-chopping开关进行脉冲压缩,产生了峰值520 kV、半高宽0.5 ns、功率1.8 GW的高压脉冲。基于Child-Langmuir定理,设计了刀刃阴极X光管,在520 kV电压下的运行阻抗为150 Ω,管前20 cm处的X射线峰值能量注量率约为1×10¹⁶ MeV·cm^-2·s^-1,累积照射量为4.1 mR。     

紧凑型纳秒高压脉冲发生器研制

研制了一台紧凑型纳秒高压脉冲发生器。该发生器主要由铁芯变压器、脉冲形成线、油间隙自击穿开关组成。在变压器和形成线之间加入了一个50 pF的谐振电容和1.15 mH的谐振电感,通过三谐振设计,使发生器在不降低输出电压的情况下,降低了变压器次级绕组的电压,实现了脉冲发生器小型化。对该发生器进行了详细的设计、模拟和实验,结果表明：该发生器可在二极管上输出峰值约500 kV、脉宽2.2 ns的高压脉冲;电子束二极管产生的X射线在距二极管靶窗20 cm处辐射剂量为20 mR,可用于辐射探测系统闪烁体的时间响应测量。     

A compact high-voltage pulse generator using a rotary airhole sparkgap

A pulsed-corona-discharge nonthermal plasma technique offers the advantages of energy efficiency and capability for the simultaneous removal of coexisting pollutants. The key to success in a nonthermal plasma approach is to produce a corona discharge in which the bulk of the electrical energy goes into the production of energetic electrons, rather than into gas molecules heating. By driving the nonthermal plasma reactor with very short pulses of high-voltage, short-lived corona discharge plasmas are created that consist of energetic electrons, which in turn produce the radicals and ozone responsible for the decomposition of the toxic molecules. Because of the short lifetime of the pulsed corona discharge, little electrical power is dissipated in movement of heavy molecule ions in the processing region, thus avoiding heating the gas and providing good electrical energy efficiency.A high-voltage pulse generator with a rotary airhole sparkgap, instead of a conventional rotary ball sparkgap, has been proposed. Its rise and fall time characteristics to be used as a smart pulse generator for pulsed corona discharge-type nonthermal plasma reactor were investigated. Parametric studies showed that the proposed airhole sparkgap had a very fast rise time, very short fall time, very low-and-stable breakdown voltage, and reliable pulse repetition characteristics, compared with the conventional rotary ball sparkgap.     

Formation stage of a high-voltage pulsed discharge in a long tube

A study was made of discharges in long tubes (d 60–132 cm) in hydrogen through an analysis of the oscillograms of the discharge current and voltage pulses and through a photometric study. As the pressure increases from 0.4 to 5 torr and as the overvoltage decreases from 290 to 90%, the step current I_st decreases, while the times t_d, t_st, and t_f, which characterize the formation stage, increase. It is thus possible that the step forms as a result of the conversion of the avalanche-streamer maximum at the beginning of the formation stage to a cathode-directed streamer. The value pd 300 torr · cm found under the experimental conditions of this study corresponds to a transitional discharge mechanism.Translated from Izvestiya VUZ. Fizika, No. 8, pp. 128–133, August, 1970.The authors thank A. Ya. Sytnik for assistance in the measurements.     

紧凑型X箍缩脉冲功率发生器

为研究丝阵负载对X箍缩的影响,设计了一台紧凑型脉冲功率发生器。介绍了该脉冲功率发生器的设计及初步实验。根据装置的结构特点,研制了一种利用金属膜连接传输线外筒与负载内筒,构成回路测量负载电流的探头。结果表明:在对Marx电容器充电60 kV时,输出电流峰值117 kA,脉宽 60 ns,上升沿22 ns,该装置已经成功箍缩出X射线。     

紧凑型X箍缩脉冲功率发生器

为研究丝阵负载对X箍缩的影响,设计了一台紧凑型脉冲功率发生器。介绍了该脉冲功率发生器的设计及初步实验。根据装置的结构特点,研制了一种利用金属膜连接传输线外筒与负载内筒,构成回路测量负载电流的探头。结果表明:在对Marx电容器充电60 kV时,输出电流峰值117 kA,脉宽 60 ns,上升沿22 ns,该装置已经成功箍缩出X射线。     

用于脉冲中子探测器的小型化高压模块性能研究

高压电源的性能特性对闪烁中子探测器的性能有着十分重要的影响。为克服传统高压供电设备体积大、便携性差的问题,在便携式脉冲中子探测器研制中拟采用内部集成小型化高压模块为光电倍增管提供高压的技术路线。根据实验结果,选用的高压模块最高输出高压可达2.5 kV并且具有良好的输出一致性,可适应16~36 V的工作电压,连续工作稳定性及温度稳定性优良,可以满足脉冲中子探测器研制的要求。     

Unsteady surface signature of a pulsed vortex generator jet

Abstract  

Porous pressure-sensitive paint (PSP) is employed as a visualization technique for unsteady flow features on a low-pressure turbine blade. Recognizing that the measurement of high-frequency pressure fluctuations in unsteady flows—especially in turbomachinery—has proven to be difficult, recent advancements in the development of porous PSP have enabled the high-resolution measurement of pressure fields with frequency content of at least 20 kHz. In this work, PSP is applied to an L1A low-pressure turbine blade section (Re = 20,000 based on axial chord) to visualize the surface dynamics of a vortex generator jet (VGJ) pulsed at 10.6 Hz with nitrogen gas. Intensity-based, time-resolved PSP measurements reveal the development and the surface structure of the VGJ as well as the spanwise variation in the blowing profile.     

PPCP用固态脉冲电源的实验研究

介绍了一种采用半导体开关与磁开关、可饱和脉冲变压器相结合技术的固态脉冲电源,此电源可用于脉冲放电等离子体烟气治理。在理论分析的基础上建立了实验模型,通过实验验证了此类电源的可行性,解决了8支晶闸管开关串联的动静态均压及开通同步性问题,并对可饱和脉冲变压器及磁开关的工作特性进行了分析计算。电源在阻性负载上得到峰值电压37.5 kV、前沿101 ns、脉宽1 μs的脉冲,重复频率300 Hz,输出功率10 kW。     

PPCP用固态脉冲电源的实验研究

 介绍了一种采用半导体开关与磁开关、可饱和脉冲变压器相结合技术的固态脉冲电源,此电源可用于脉冲放电等离子体烟气治理。在理论分析的基础上建立了实验模型,通过实验验证了此类电源的可行性,解决了8支晶闸管开关串联的动静态均压及开通同步性问题,并对可饱和脉冲变压器及磁开关的工作特性进行了分析计算。电源在阻性负载上得到峰值电压37.5 kV、前沿101 ns、脉宽1 μs的脉冲,重复频率300 Hz,输出功率10 kW。     

Rates and channels of water ionization by a high-current high-voltage pulsed discharge

The experimentally observed growth of the plasma density in a high-current high-voltage pulsed discharge in a liquid medium is compared with the results of calculations based on the effective cross sections for electron-impact ionization and other elementary processes. It is found that, in the initial stage of the discharge, the plasma density grows linearly with time, whereas at densities above 3 × 10¹⁰ cm^?3, the growth becomes exponential due to the collective acceleration of plasma electrons. The gas-vapor fraction of the water medium is ionized by two groups of electrons: low-energy electrons, with energies about several tens of electronvolts, and high-energy ones, with energies in the kiloelectronvolt range. The energy spent on water ionization is estimated and is found to be several times higher than the energy required to ionize a rarefied gas.     

A microprocessor-controlled apparatus for the measurement of pulsed spectra

A simple and relatively inexpensive microprocessor-controlled apparatus to measure pulsed spectra has been developed. The system enables the average for a given number of pulses to be taken at each data point. Spectra of a mercury lamp are presented as an example.Work supported by CNR through the Progetto Finalizzato Laser di Potenza.