共查询到20条相似文献,搜索用时 268 毫秒
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为研究理论模型关联式对内螺纹管内流体冷凝压降的预测效果,本文首先对管内压降产生机制、理论模型拟合机理进行了阐述,而后基于4种内螺纹管内R1234yf流动冷凝压降实验数据,对所选的5个分相模型关联式、2个均相模型关联式的预测效果进行了校核。校核结果显示:由于关联式对管内流体流动机制的假设工况与流体实际流动工况相近,文献[12]、[13]提出的关联式对管内压降表现出较好的预测效果,而文献[8]、[15]基于人字齿管压降数据拟合的关联式均不适用于管内压降的预测,此外,文献[16]、[18]提出的均相模型关联式对管内压降的预测误差虽不大,但预测精度受肋片结构的影响较大。 相似文献
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介绍了一种用于测试X波段加速管中高阶模电场分布的笼子式微扰体的研制与标定,该微型拢动体通过专门设计加工的固定装置,在尼龙线表面平行沉积溅射数根金属丝膜制成,利用一标准圆柱腔,对笼子式扰动体的扰动因子进行了定标,证实金属丝笼子式拢动体与同外形尺寸的金属圆筒相比,具有高分辨率、高灵敏度的优点,采用笼子式拢动体测试了一根长30cm的X波段加速管中TM110模的纵向电场分布。 相似文献
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A. N. Didenko A. E. Shikanov V. I. Rashchikov V. I. Ryzhkov V. L. Shatokhin 《Technical Physics》2014,59(6):904-910
The generation of neutron pulses with a duration of 1–100 ns using small vacuum accelerating tubes is considered. Two physical models of acceleration of short deuteron bunches in pulse neutron generators are described. The dependences of an instantaneous neutron flux in accelerating tubes on the parameters of pulse neutron generators are obtained using computer simulation. The results of experimental investigation of short-pulse neutron generators based on the accelerating tube with a vacuum-arc deuteron source, connected in the circuit with a discharge peaker, and an accelerating tube with a laser deuteron source, connected according to the Arkad’ev-Marx circuit, are given. In the experiments, the neutron yield per pulse reached 107 for a pulse duration of 10–100 ns. The resultant experimental data are in satisfactory agreement with the results of computer simulation. 相似文献
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研制了一种双极性交替的纳秒高压脉冲电源,进行了双极性纳秒脉冲放电产生等离子体研究。该电源先通过固态开关IGBT将直流电压截断成电压脉冲,通过可饱和脉冲变压器拓扑,实现升压并缩短脉冲上升沿。该电源可在一个周期内输出极性相反的2个脉冲,且时序可以灵活控制。通过优化调整器件参数,研制了两种不同输出性能参数的双极性纳秒脉冲电源:①峰值电压10 kV、爆发模式脉冲重复频率500 kHz(正负脉冲间隔2 μs)、连续重复频率1 kHz;②峰值电压25 kV、爆发重频200 kHz、连续重频600 Hz。测试电源的运行性能,发现电源存在温度升高的情况,但长时间(>0.5 h)运行温度趋于稳定。10 kV电源连续运行在1 kHz时最高温度点50.5 ℃;25 kV电源连续运行在600 Hz时最高温度点60 ℃。利用该电源驱动线板电极阵列和表面介质阻挡放电结构,证实了该电源可以用于常压空气条件下产生大面积等离子体。 相似文献
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A new method of pumping electric-discharge gas lasers and excimer lamps is proposed on the basis of generators with inductive
energy storage and opening switches of various types (exploding wires, gas-discharge low-pressure devices, plasma erosion
opening switches, and semiconductor SOS diodes). It is shown that the inductive energy storage provides a convenient way of
varying the pump pulse parameters (primarily, the pulse duration and the input power) and obtaining optimal excitation pulses
for various types of lasers. The potential of using generators with inductive energy storage for pumping gas lasers is demonstrated.
Original Text ? Astro, Ltd., 2006. 相似文献
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New types of high-voltage pulse generators based on spiral striplines are studied experimentally. A new theoretical model
of these generators is suggested. Some of the generators demonstrate a high (25–50%) efficiency. A functional breadboard of
a pulsed X-ray apparatus based on a modified spiral generator is designed. The output parameters of the apparatus are sufficient
to detect fast processes. 相似文献
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PFN-Marx发生器可同时实现升压和脉冲形成,具有紧凑的基因。特别是近年来脉冲储能技术的发展,使得直接利用PFN-Marx发生器驱动各类负载成为现实,因而PFN-Marx发生器逐渐成为国内外研究热点。对国内外的高功率紧凑PFN-Marx发生器的研究进展进行了系统介绍,评述其参数和结构特点。通过总结,从时间发展历程上看,PFN-Marx发生器采用高储能密度器件,装置的储能密度水平在不断地提高,尺寸紧凑化水平也在提高;在追求紧凑化的手段上,PFN-Marx发生器的空间结构的优化设计效果优于PFN网络拓扑参数的优化设计;PFN-Marx发生器采用波形优化方法具有较明显的收益,可有效降低装置紧凑化带来级间分布参数更强耦合的负面影响。同时论文探讨了PFN-Marx发生器的发展趋势,为PFN-Marx发生器的研究和技术路线探索提供参考和依据。 相似文献
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为了调节固态Marx发生器输出脉冲的边沿,提出了一种新型的的驱动电路,该方案通过调整充放电管的驱动电压,结合驱动电路的硬件结构,调节米勒平台时间,进而调整充放电管开通速度,实现了对于高压输出脉冲的边沿调节,其结构简单,不需要每级独立的控制信号。对于该电路中驱动电压和开关管开通速度的关系建立了模型进行了推导。结合理论分析结果设计了驱动电路的参数,仿真结果表明该驱动电路能够调节输出脉冲边沿。搭建带有设计参数下驱动电路的固态Marx发生器在容性负载下和阻性负载下进行了实验验证。利用该方案实现了对于6级Marx电路的3.6 kV输出脉冲在55~7.7μs的边沿调节,验证了该方案的可行性,并对比分析了不同阻性负载对于脉冲边沿造成的影响。实验结果表明:该电路在提高固态脉冲电源的边沿调节性能方面有独特的优势。 相似文献
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Engel T.G. Kaplicki C. Nunnally W.C. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(5):1377-1381
The analysis, design, and operation of high-voltage, transformer-coupled LC vector inversion generators are presented and discussed. The transformer-coupled LC inversion generator is easy to construct and, compared with Marx-type generators and conventional LC vector inversion generators, requires only one inversion switch, independent of the number of voltage multiplication stages. The transformer-coupled LC generator, therefore, satisfies a niche area need for some high-voltage pulse applications. The primary factor that limits the performance of the transformer-coupled LC generator is magnetic saturation in the transformer core. This investigation develops theoretical scaling relationships for magnetic saturation in the transformer core and other performance-limiting factors. The results of transformer-coupled LC vector inversion generator numerical simulations are also compared with theoretical results 相似文献