scholarly journals A coaxial-output rolled strip pulse forming line based on multi-layer films

2018 ◽  
Vol 36 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Jian-Cang Su ◽  
Rui Li ◽  
Jie Cheng ◽  
Bin-Xiong Yu ◽  
Xi-Bo Zhang ◽  
...  
Keyword(s):  
Rise Time ◽  
Axial Direction ◽  
Output Pulse ◽  
Rolled Strip ◽  
Strip Line ◽  
Matched Load ◽  
Multi Stage ◽  
Output Electrode ◽  
In Series ◽  
Discharging Characteristic

AbstractA coaxial-output rolled strip pulse-forming line (RSPFL) with a dry structure is researched for the purpose of miniaturization and all-solid state of pulse-forming lines (PFL). The coaxial-output RSPFL consists of a coaxial-output electrode (COE) and a rolled strip line (RSL). The COE is characterized by quasi-coaxial structure, making the output pulse propagate along the axial direction with a small output inductance. The RSL is rolled on the COE, whose transmission characteristics are analyzed theoretically. It shows that the RSL can be regarded as a planar strip line when the rolling radius of the strip line is larger than 60 times of the thickness of the insulation dielectric layer of RSL. CST modeling was carried out to simulate the discharging characteristic of the coaxial-output RSPFL. It shows that the coaxial-output RSPFL can deliver a discharging pulse with a rise time <6 ns when the impedance of the RSL matches that of the COE, which confirms the theoretical analysis. A prototype of the coaxial-output RSPFL was developed. A 49-kV discharging pulse on a matched load was achieved when it was charged to 100 kV. The discharging waveform has a pulse width of 32 ns, with a rise time of 6 ns, which is consistent with the simulation waveform. An energy-storage density of 1.9 J/L was realized in the coaxial-output RSPFL. By the method of multi-stage connection in series, a much higher output voltage is convenient to be obtained.

An air insulated linear pulse transformer for electrodischarge technology

2021 ◽  
Vol 16 (12) ◽  
pp. P12006
Author(s):  
A.A. Zherlitsyn ◽  
V.M. Alexeenko ◽  
S.S. Kondratiev
Keyword(s):  
Output Pulse ◽  
Pulse Transformer ◽  
Wide Field ◽  
Matched Load ◽  
Charge Voltage ◽  
Mode Of Operation ◽  
In Series ◽  
Linear Pulse ◽  
A Charge ◽  
Transformer Output

Abstract A linear pulse transformer with air insulation at atmospheric pressure was created and tested under both constant resistance and non linear loads. The maximum power of the transformer output pulse reached ∼500 MW at a matched load with a charge voltage 50 kV. The transformer transferred ∼60% of the stored energy to the load over a characteristic time of about 1 μs. The scalability the generator was studied by connecting two identical transformers in series which gave a power output of ∼850 MW with doubled output voltage and reduced current. The frequency mode of operation was studied using one and two transformers with a charge voltage of 50 kV and a load that was, close to matched. In both cases, the power maximum and jitter showed no significant changes at any of the frequencies tested (up to 5 Hz). These results mean that the use of this generator can be recommended for a wide field of applications due to its scalability and low internal impedance.

scholarly journals Development and testing of a three-section pulse-forming network and its application to Marx circuit

2019 ◽  
Vol 37 (4) ◽  
pp. 408-414
Author(s):  
Falun Song ◽  
Beizhen Zhang ◽  
Chunxia Li ◽  
Fei Li ◽  
Ganping Wang ◽  
...  
Keyword(s):  
Rise Time ◽  
Design Parameters ◽  
Marx Generator ◽  
Output Waveform ◽  
Pulse Forming Network ◽  
Multi Stage ◽  
Output Peak Power ◽  
In Series ◽  
Type C ◽  
Compact Design

AbstractA three-section pulse forming network (PFN) based on Guillemin type-C circuit was developed to meet the challenge of a compact design, high withstand voltage, and high-quality output waveform with fast rise time, flat-top duration, and 100-ns pulse width. A simplified pulse forming circuit was proposed and studied that includes only three LC-sections connected in parallel, with each section containing an inductor and a capacitor connected in series. The effect of the capacitance deviation on the output waveform was investigated. The simulation results show that when the capacitance deviation exceeds +3%, both the flat top and fall time of the output waveform of single PFN module deteriorate greatly. Fortunately, in a multi-stage PFN-Marx circuit, even if the capacitance deviation exceeds +10%, when the average capacitance of the same LC sections is close to the theoretical value, the output waveform maintains a good quality and is in good agreement with the theoretical prediction. The compact three-section PFN developed during this project has a size of only 360 mm × 342 mm × 65 mm, and a maximum withstand voltage of 120 kV. Sixteen PFN stages were assembled to form a Marx generator with design parameters to provide of an output peak power of 12 GW and a maximum peak current of 15 kA. The tested output waveform agrees well with the theoretical results, having a rise time of 31 ns, a flat-top of 104 ns, and a pulse with of 164 ns.

Assessment of a Novel Non-Axial Counter-Rotating Compressor Concept for Aero-Engines

2018 ◽  
Author(s):  
Quentin Dejour ◽  
Huu Duc Vo
Keyword(s):  
Pressure Rise ◽  
Axial Direction ◽  
Boundary Layer Separation ◽  
Low Flow ◽  
Compressor Stage ◽  
Mixed Flow ◽  
Stall Margin ◽  
High Loss ◽  
Multi Stage ◽  
Flow Compressor

This paper presents the first assessment of a new non-axial counter-rotating compressor concept. This concept consists of replacing the stator of a mixed-flow compressor stage or the diffuser of a centrifugal compressor stage with a counter-rotating rotor that will turn the flow back to the axial direction with much lower diffusion factor, while providing the equivalent in work of the upstream mixed-flow rotor or impeller. This concept has two advantages. First, the very high stage pressure rise means that only a single counter-rotating rotor may be required, making mechanical implementation simpler than for multi-stage axial counter-rotating compressors. Second, the replacement of the high flow turning (high loss) stator/diffuser in a non-axial stage with a low flow turning counter-rotating rotor gives the new concept potential for achieving higher efficiency than conventional non-axial compressors. As a first proof of concept, a subsonic counter-rotating mixed-flow compressor and its conventional (i.e. rotor-stator) equivalent have been designed with the intent of being implemented in a test rig. CFD simulations have been carried out for a comparative evaluation of both configurations. Results show that the counter-rotating mixed-flow compressor produces more than double the pressure rise of its conventional version with a slightly higher peak-efficiency while having a smaller axial length. Moreover, the counter-rotating configuration has a better stall margin than its conventional counterpart, for which the boundary layer separation from excessive flow turning in the stator causes early stall.

Development of a Pulsed Power Supply Utilizing 13 kV Class SiC-MOSFETs

2020 ◽  
Vol 1004 ◽  
pp. 1141-1147
Author(s):  
Katsuya Okamura ◽  
Fujio Naito ◽  
Ken Takayama ◽  
Hidenori Kitai ◽  
Hisato Michikoshi ◽  
...  
Keyword(s):  
Rise Time ◽  
Short Pulse ◽  
Load Resistance ◽  
Pulsed Power ◽  
Circuit Board ◽  
Resistive Load ◽  
Circuit Boards ◽  
Pulse Switching ◽  
2Nd Generation ◽  
In Series

To resolve the drawback of conventional thyratron switches, development of a semiconductor high voltage switch utilizing a 13 kV class SiC-MOSFET developed by Tsukuba Power Electronics Constellations (TPEC) is proceeding. At first, the device evaluation test was carried out with a resistive load circuit. With the conditions of drain voltage of 10 kV and load resistance of 1 kΩ, turn on loss Eon, turn off loss Eoff, rise time Tr and fall time Tf were 1.7 mJ, 1.1 mJ, 64 ns, and 75 ns, respectively. Thereafter, the 2s-12p switch array was designed and assembled, where 12 MOSFETs are equally aligned on a circle shaped circuit board and two circuit boards are stacked in series. An 18 kV-318 A-1 us pulse with a rise time of 289 ns in the short pulse switching test were successfully demonstrated. Moreover, switching tests of 2nd generation MOSFET that has a twice larger device area was conducted. As a result, 60 % reduction of on-resistance was confirmed.

Separation of Azeotropic Mixture Using Multi-stage Ultrasound-Assisted Flash Distillation

2015 ◽  
Vol 10 (4) ◽  
pp. 237-242 ◽  
Author(s):  
Taha Mahdi ◽  
Arshad Ahmad ◽  
Adnan Ripin ◽  
Mohamed Mahmud Nasef
Keyword(s):  
Ethyl Acetate ◽  
Azeotropic Mixture ◽  
Separation Unit ◽  
Multi Stage ◽  
Azeotropic Mixtures ◽  
In Series ◽  
Flash Distillation ◽  
Ultrasound Assisted ◽  
Aspen Custom Modeler

Abstract A mathematical model for an ultrasound-assisted vapor liquid equilibrium (VLE) system developed in Aspen Custom Modeler is exported to Aspen Plus flowsheeting environment to form a block in the software library to represent a single stage flash separation unit. The block is then arranged in series to mimic an ultrasonically intensified distillation process. As a case study, an ethanol/ethyl acetate separation process is examined. The results show that a 99 mol% ethyl acetate recovery is established when a series of 27 flash VLE devices are used. The system is also evaluated for other minimum boiling azeotropic mixtures, and consistent results are obtained, thus revealing the potentials of ultrasound-assisted system as an alternative strategy for azeotropic mixture separations.

scholarly journals Study on strip spiral Blumlein line for the pulsed forming line of intense electron-beam accelerators

2009 ◽  
Vol 27 (1) ◽  
pp. 95-102 ◽  
Author(s):  
J.L. Liu ◽  
X.B. Cheng ◽  
B.L. Qian ◽  
B. Ge ◽  
J.D. Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Output Voltage ◽  
Beam Quality ◽  
Characteristic Impedance ◽  
Output Pulse ◽  
Voltage Waveform ◽  
Matched Load ◽  
Intense Electron Beam ◽  
Blumlein Line ◽  
Intense Electron

AbstractThe pulse forming line (PFL) is the key part of the intense electron-beam accelerators (IEBA), which determines the quality and characteristic of the output beam current of the IEBA. Compared with the accelerator with traditional Blumlein line, an IEBA based on strip spiral Blumlein line (SSBL) can increase the duration of the output pulse in the same geometrical dimension. But the disadvantage of the SSBL is that the output voltage waveform at the matched load may be distorted, which influences the electron beam quality. In this paper, according to the electromagnetic theory, formulas for calculating the main electric parameters of SSBL (inductance, capacitance, transmission time, and characteristic impedance) are deduced. The effect of the geometric parameters of SSBL on the slowing coefficient is analyzed. The designed condition of SSBL for the output ideal voltage pulse in the matched load is obtained by theoretical analysis. Furthermore, the Karat code is used to simulate the output voltage waveform of SSBL on the matched load for different spiral angels. At last, a couple of contrastive experiments are performed on an electron-beam accelerator based on the SSBL with water dielectric. The experimental results agree with the theoretical and simulated results.

Pumping Capacity of Pitched Blade Multi-Stage Impellers

2014 ◽  
Vol 35 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Tomáš Jirout
Keyword(s):  
Axial Velocity ◽  
Laser Doppler Anemometry ◽  
Velocity Profiles ◽  
Circulation Loop ◽  
Geometrical Parameters ◽  
Main Attention ◽  
Blade Number ◽  
Multi Stage ◽  
In Series ◽  
Close Distance

Abstract This paper extends knowledge about flow in an agitated batch with pitched blade multi-stage impellers. Effects of various geometrical parameters (blade number, distance between impellers) of pitched blade multi-stage impellers on pumping ability have been investigated. Axial velocity profiles were measured by LDA (Laser Doppler Anemometry). Axial pumping capacities were obtained by integration of measured axial velocity profiles in outflow from impellers. Main attention was focused on the effect of the distance between impellers in multi-stage configurations, on their pumping capacity and flow in the mixing bath in comparison with an independently operating pitched blade impeller with the same geometry. In case of a relatively close distance between impellers H3/d = 0.5 - 0.75, the multi-stage impeller creates only one circulation loop and the impellers itself behave identically as pumps in series. However for relative higher distance of impellers than H3/d = 1.25, the multi-stage impeller creates two separated circulation loops.

scholarly journals 40 GW Linear Transformer Driver stage for pulse generators of Mega-ampere range

2009 ◽  
Vol 27 (3) ◽  
pp. 371-378 ◽  
Author(s):  
B.M. Kovalchuk ◽  
A.V. Kharlov ◽  
A.A. Zherlitsyn ◽  
E.V. Kumpjak ◽  
N.V. Tsoy ◽  
...  
Keyword(s):  
High Voltage ◽  
Rise Time ◽  
Inertial Confinement Fusion ◽  
Pulse Length ◽  
Output Pulse ◽  
Inertial Confinement ◽  
High Current ◽  
High Current Electronics ◽  
Isentropic Compression ◽  
Linear Transformer Driver

AbstractLinear transformer driver (LTD) technology is actively developed at the Institute of High Current Electronics in Tomsk, Russia. This technology is being examined for use in high current high voltage pulsed accelerators. Recent development of high voltage low inductance capacitors and low inductance switches enabled to achieve ~100 ns rise time of the LTD output pulse. This technique allows one to eliminate intermediate pulse forming sections, used in the present accelerator technology, which would keep the footprint of an LTD accelerator small. LTD based drivers are currently considered for many applications, including future very high current Z-pinch drivers for inertial confinement fusion, medium current drivers with adjustable pulse length for isentropic compression experiments, and finally relatively low current accelerators for radiography and X-pinches. In this article, we present the design and test results for a new LTD stage, that operates at 100 kV charging voltage. Current amplitude up to 850 kA with ~140 ns rise time was obtained on a 0.05 Ω load. Stack of the LTD stages can be easily assembled in series or in parallel, thus providing voltage or current multiplication, respectively. Design of multi-mega-volt and multi-mega-ampere generators becomes straightforward with the LTD technology.

Dome-Shaped High Power Transformer for Driving A 61 W T5 Lamp

2007 ◽  
Vol 544-545 ◽  
pp. 231-234
Author(s):  
Man Soon Yoon ◽  
Il Ho Kim ◽  
Soon Chul Ur
Keyword(s):  
High Power ◽  
Power Efficiency ◽  
Power Transformer ◽  
Temperature Stability ◽  
Powder Injection ◽  
Curvature Radius ◽  
Piezoelectric Transformer ◽  
Power Characteristics ◽  
Output Electrode ◽  
In Series

Processing and properties of a dome-shaped piezoelectric transformer with a composition of 0.03Pb(Sb0.5Nb0.5)O3-0.03Pb(Mn1/3Nb2/3)O3-0.465PbTiO3-0.475PbZrO3 have been investigated. A dome-shaped sample was fabricated by powder injection molding. The dimension of the domeshaped sample was a 28 mm in diameter and 2.1mm in thickness with a curvature radius of 18 mm. Finite element modeling for the complicated piezoelectric transformer was applied to simulate strains and vibration mode in the sample. The high power characteristics of a dome-shaped piezoelectric transformer were examined by the lighting test for 27 and 34 watt T5 circle lamps connected in series. The series connected T5 circle lamps were successfully driven by the domeshaped piezoelectric transformer with sustaining efficiency higher than 98.5%. The transformer with ring(input)/dot(output) electrode ratio of 2.5 exhibited the maximum properties in terms of output power, efficiency and temperature stability.

scholarly journals ENHANCED PERFORMANCE OF MULTI-STAGE ANAEROBIC DIGESTION OF TOFU WASTEWATER: ROLE OF RECIRCULATION

2019 ◽  
Vol 10 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Hanny Vistanty ◽  
Rizal Awaluddin Malik
Keyword(s):  
Anaerobic Digestion ◽  
Ph Value ◽  
Anaerobic Reactors ◽  
Multi Stage ◽  
Recirculation System ◽  
In Series ◽  
And Performance ◽  
Anaerobic System

Continuous three-stage anaerobic reactors with recirculation system were employed to treat real tofu wastewater. The system consists of 3 reactors connected in series and effluent of the last reactor was partly returned as feed of the first reactor along with fresh wastewater. The recirculation system was conducted on four variations of recirculation ratio (RR)s of 0, 1.0, 1.3, and 1.5 to evaluate the influence of recirculation on stability and performance of anaerobic system. Results showed that recirculation improved the performance of anaerobic digestion. COD was fluctuated without recirculation and gradually decreased to 373 and 298 mg/L at RR 1.3 and 1.5, respectively. Likewise, pH value was dropped to 6.5 at RR 0, and started to increase to approximately 8.0 upon employing recirculation. In addition, the system also showed excellent toleration against rise in ammonia loading, with effluent ammonia approximately 4.678 mg/L. The findings showed that the system employed had excellent efficiency and stability in treating tofu wastewater. 

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