Electrical Wire Explosion Research Articles

Enhancement of underwater shock wave by coupling electrical explosion and al-powder-suspension combustion: Facing advanced reservoir stimulation technology

The development of fossil energy requires eco-friendly and high-efficient approaches, especially in contemporarily low-carbon scenarios. Using the high-power pulsed discharge to induce fractures has drawn increasingly academic and industrial attention in reservoir stimulation. Therein, the electrical wire explosion is commonly adopted as the pulsed discharge load to transfer electrical energy to mechanical one (shock wave and plasma bubble) efficiently. To strengthen mechanical loadings, a discharge capsule with a metallic wire inside Al-powder suspension has been designed and tested. Experiments were performed with a μs-timescale pulsed power source with stored energy from 150 to 750 J, and the electrical explosion were diagnosed via high-speed photography, electrophysical, and mechanical measurements. The experiment shows that there is an optimal concentration of Al-powder suspension in order to obtain the maximum peak pressure of shock wave for a given discharge condition. Too high or low concentrations of the aluminum powder will cause a lower peak pressure. This paper shows that at the stored energy of 500 J, when the concentration of Al-powder suspension is 20 g/L, the peak pressure can reach 4.81 ± 0.27 MPa, which is 2.01 times as large as the shock wave generated by the electrical explosion under the same conditions in pure water. Through the electrophysical measurement, it is found that the aluminum powder almost does not affect the phase transition of the wire. However, in the subsequent plasma formation, the gaseous reaction products make the discharge channel more complex and in a higher pressure density state, which is shown by the increase of channel resistance. Through the backlit images taken by the high-speed camera, it is obvious that two discrete strong shock waves can be seen in the Al-powder-suspension environment.

Underwater pressure waves generated by electrical exploding wire ignited energetic materials: Parametric study and formulation optimization

The combination of electrical wire explosion and low sensitivity energetic materials (EMs) is an efficient and practical method to generate controllable strong pressure waves (PWs), which is receiving extensive attentions in dynamic fracturing related applications. In this paper, the performance of a mud-like EM formulated with aluminum thermite and nitromethane is analyzed experimentally and statistically. Aluminum microparticles (Al MPs) of five different size distributions are tested and the −300 mesh Al MPs is identified as the preferred additive. In order to establish the mathematical relationship between the EM formulation and the PW parameters, the measured pressure profile is reconstructed based on the ignition mechanism to enable parameter extraction, and a statistical model is then developed with back-propagation neural network and data augmentation. Based on the model, the influence of EM components on the pressure pulse parameters is summarized and optimal formulations are proposed.

Experimental and numerical investigation on electrical wire explosion in pulse plasma systems

Simulation and experimental studies have been used in this paper regarding the importance of the plasma pulse system (PPS) to create a uniform discharge plasma channel and a strong shock wave. First, the effect of wire geometry on uniform plasma production is simulated. The simulation results show that a wire with a diameter of 0.4 mm and a length of 50 mm is an ideal geometry for the plasma pulse system because it produces a more uniform plasma. Second, the shock wave generation mechanism was investigated experimentally in the explosion process of two wires with thicknesses of 0.2 and 0.4. As the diameter of the wire increases and its resistance decreases, the discharge current peak increases, and the tendency to establish periodic currents increases, so the 0.4 wire gives better experimental results in terms of shock wave power than the simulation results that confirms the smaller the diameter of the wire, the current generated in a pulsed manner in a short period, and sufficient energy is not stored to change the state of the wire and, as a result, to create a strong shock wave in the wire. Finally, it simulated underwater using COMSOL Multiphysics. It shows that the pressure drops immediately after the explosion point. Based on this, a pressure of 20 MPa has been obtained at a distance of 10 cm from the explosion point, and this reduction rate continues exponentially.

Bicomponent Zno-Ag janus nanoparticles with high antitumor activity <I>in vitro</I>

Background. Nanoparticles (NPs) of zinc and silver oxide are promising antitumor agents, the use of which can enhance modern approaches to cancer treatment. Using bicomponent ZnO-Ag nanoparticles, one can increase the efficiency due to the occurrence of a synergistic antitumor effect. Among the main physicochemical properties that affect the antitumor activity of nanoparticles, one can distinguish their size and distribution of components inside the particle or their microstructure, however, these aspects are currently poorly understood.The aim of this study is the synthesis of ZnO-Ag nanoparticles using electrical explosive of wire technology and the in vitro study of the antitumor activity of NPs against breast ductal adenocarcinoma MCF-7 (ATCC HTB-22) and the HeLa cell line isolated from a cervical tumor.Material and Methods. ZnO-Ag nanoparticles were obtained by simultaneous electric explosion of zinc and silver twisted wires in a gas mixing atmosphere: argon and oxygen. The content of the components was regulated by varying the wire diameters. Physicochemical properties were studied using X-ray phase analysis, thermal desorption of nitrogen, and transmission electron microscopy. Antitumor activity in vitro was studied using the MTT test against HeLa and MCF-7 cell lines.Results. As a result of an electric explosion of twisted wires in an argon + oxygen gas mixture, ZnO-Ag NPs with different contents of components and the structure of Janus nanoparticles were obtained. The study of the physicochemical properties of nanoparticles showed that an increase in the silver content led to a decrease in the average particle size, an increase in their specific surface area, an increase in their photochemical activity and the ability to generate reactive oxygen species. The high antitumor activity of nanoparticles with a minimum silver content can be explained by a decrease in the size of silver fragments from 46 nm to 23 nm and a decrease in the average particle size from 92 nm to 54 nm. A decrease in the size of NPs and their components contributes to an increase in their solubility and, accordingly, cytotoxicity. In addition, a decrease in the size of crystallites makes it possible to increase the number and length of the ZnO-Ag interface.Conclusion. In the present study, bicomponent ZnO–Ag NPs were synthesized using the joint electric explosion of zinc and silver wires in a mixed atmosphere of argon and oxygen. A study of the physicochemical properties of nanoparticles was carried out and it was found that they all have the structure of Janus nanoparticles, an average size of 54 to 92 nm, and photochemical activity and the ability to generate ROS. Using the MTT test, the antitumor activity of NPs was confrmed using MCF-7 and HeLa cell lines. The high effciency of ZnO-Ag NPs containing 20% wt. silver indicates the possibility of using these NPs in antitumor therapy.

Magnetocaloric effect of FeNi magnetic nanoparticles obtained by the electrical explosion of wire technique

In this work the structure, magnetic properties and of the magnetocaloric effect of the large batches of magnetic FeNi nanoparticles were studied for selected compositions close to the invar. Nanoparticles were synthesized by the method of the electric explosion of wire using various technological parameters ensuring the difference in their dispersion parameters. The main variable parameter was the degree of overheating of the wire material. The use of different technological conditions for obtaining batches of nanoparticles ensured the difference in their dispersion parameters. Keywords: electric explosion of wire, magnetic nanoparticles, invar composition, magnetic properties, magnetocaloric effect.

Магнитные композиты на основе эпоксидной смолы с магнитными микро- и наночастицами оксида железа: фокус на магнитное детектирование

Magnetic and structural properties iron oxide micro- and nanoparticles and composites based on epoxy resin at different mass concentrations of particles are investigated (0, 5, 10, 30%). Commercial Alfa Aesar microparticles and nanoparticles obtained by electric explosion of wire with different dispersion parameters were compared. Magnetoimpedance detection of stray magnetic fields of the obtained composites in the form of cylinders using a strip multilayer film element [FeNi/Cu]5/Cu/[FeNi/Cu]5 was carried out. It is shown that it is possible to determine the position of filled magnetic composites at different mass concentrations of magnetic micro- or nanoparticles with different parameters of dispersion of the ensemble using magnetoimpedance detection. Ключевые с

Магнитокалорический эффект магнитных наночастиц FeNi, полученных методом электрического взрыва проволоки

In this work the structure, magnetic properties and of the magnetocaloric effect of the large batches of magnetic FeNi nanoparticles were studied for selected compositions close to the invar. Nanoparticles were synthesized by the method of the electric explosion of wire using various technological parameters ensuring the difference in their dispersion parameters. The main variable parameter was the degree of overheating of the wire material. The use of different technological conditions for obtaining batches of nanoparticles ensured the difference in their dispersion parameters.

Molecular dynamics study of liquid–vapor transition in underwater electrical wire explosion

During underwater electrical wire explosion, liquid–vapor transitions are crucial to the energy deposition and the generation of shock waves. To explore the characteristics of liquid–vapor transition during electrical explosions in water, a large-scale molecular simulation method was designed. The modeling scales experimental exploding wires to nano-size and then tracks the motion of each atom. The surrounding water medium was simplified as an expanding wall, whose velocity was determined by experimental steak images. Using this model, the phase transition processes at different energy deposition rates were compared. The results show that high energy deposition rates can make the discontinuous liquid–vapor phase transition disappear, forming an axially uniform vapor column, while slow energy injection will change the exploding wire into a foamlike liquid–vapor mixture at a subcritical temperature. The different shapes of wire–water interfaces in the experimental shadowgraphs can be explained by these features of liquid–vapor transition.

Numerical investigation of negative polarity electrical explosion of aluminum wire in vacuum

Numerical investigation was carried out on the evolution of inhomogeneous energy deposition of polarity effects in negative polarity electrical explosion of aluminum wire in vacuum. First, radial electric field distribution of the aluminum wire was simulated. The results showed that the initial electric field near electrodes was much smaller than that in the middle of the wire. A model of electrical wire explosion based on ZEUS-EW with artificial limitation on breakdown time of the aluminum wire was used to simulate the behavior of inhomogeneous energy deposition of the polarity effect. The complete evolution process of electrical explosion of the aluminum wire with inhomogeneous energy deposition was further explored and qualitatively divided into three stages according to the simulation results. Finally, the influence of some factors on the inhomogeneous energy deposition simulation was investigated. This study provides some help for a better understanding of the polarity effect in the process of wire explosion.

A nanoparticle formation model considering layered motion based on an electrical explosion experiment with Al wires

To study the evolution of nanoparticles during Al wire electrical explosion, a nanoparticle formation model that considered layered motion was developed, and an experimental system was set up to carry out electrical explosion experiments using 0.1 mm and 0.2 mm Al wires. The characteristic parameters and evolution process during the formation of nanoparticles were calculated and analyzed. The results show that the maximum velocities of the innermost and outermost layers are about 1200 m·s−1 and 1600 m·s−1, and the velocity of the middle layer is about 1400 m·s−1, respectively. Most of the nanoparticles are formed in the temperature range of 2600 K‒2500 K. The characteristic temperature for the formation of Al nanoparticles is ∼2520 K, which is also the characteristic temperature of other parameters. The size distribution range of the formed nanoparticles is 18 to 110 nm, and most of them are around 22 nm. The variation of saturated vapor pressure determines the temperature distribution range of particle nucleation. There is a minimum critical diameter of particles (∼25 nm); particles smaller than the critical diameter can grow into larger particles during surface growth. Particle motion has an effect on the surface growth and aggregation process of particles, and also on the distribution area of larger-diameter particles. The simulation results are in good agreement with the experiments. We provide a method to estimate the size and distribution of nanoparticles, which is of great significance to understand the formation process of particles during the evolution of wire electrical explosion.

Addressing the critical parameters for overdamped underwater electrical explosion of wire

Experimental and magnetohydrodynamic numerical simulation results and analysis of a μs- and sub-μs-timescale overdamped underwater electrical explosion of copper wires having different lengths and diameters are presented. For these explosions, ∼80% of the energy stored in the pulse generator is deposited into the wire during a time comparable or shorter than a quarter period of the underdamped discharge. It was found that the threshold values of the deposited energy density, energy density rate, and energy density per unit area, which satisfy overdamped discharge, depend on the wire parameters and on the timescale of the explosion. It was shown that the mechanism responsible for this is the process during which the wire experiences phase transitions to a low-ionized plasma, the resistivity of which is determined by the electron–neutral collision rate, which, in turn, depends on the wire radial expansion velocity, current density, and temperature.

The Influence of Discharge Mode on Morphology of Al–Ni Nanoparticles Prepared by Underwater Electrical Wire Explosion

We report the results of experiments investigating the influence of discharge mode on morphology of Al–Ni bimetallic nanoparticles prepared by underwater electrical explosion (UEE) of intertwined Al/Ni wire. The experiments were conducted using a pulsed power generator with the stored energy of [Formula: see text][Formula: see text]J (underheat mode) and [Formula: see text][Formula: see text]J (overheat mode), delivering to the intertwined Al/Ni wire a [Formula: see text][Formula: see text]kA current rising during [Formula: see text]s. By analyzing electrical signals, we conclude that there exists a competitive process between Al wire and Ni wire, and the latter always lags behind the former in various stages, duo to the difference of electrical resistivity. Using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS), the morphology and element composition of nanopowders obtained at underheat mode and overheat mode were studied. The results reveal that core-shell structured Al–Ni nanoparticles can be easily obtained at underheat mode, due to the mismatched specific surface energy and matching lattice type between aluminum and nickel. Besides, the Al–Ni powder prepared by underwater electrical wire explosion (UEWE) has a smaller particle size (less than 100[Formula: see text]nm) and more consistent particle size distribution compared with traditional preparation methods. These results show that UEWE is very attractive for the preparation of Al–Ni nanopowders, which is helpful in improving the specific surface area of Raney–Ni catalyst.

Role of the Fe<sub>3</sub>O<sub>4</sub> mass ratio in Fe<sub>3</sub>O<sub>4</sub>-Fe nanoparticles with the core-shell structure on their anticancer activity <i>in vitro</i>

Introduction. Currently, most of the drugs used in tumor therapy are highly toxic and cause various toxic effects. Therefore, many drug delivery methods are being developed. The use of nanotechnology is one of the most promising methods. The use of magnetic iron oxide nanoparticles as antitumor agents makes it possible to prevent off-target cytotoxicity and other side effects of traditional chemotherapy. The use of nanoparticles is limited by their low efficiency. the Fe3O4/Fe galvanic couple makes it possible to control the release of toxic iron ions and, accordingly, the activity of nanoparticles. Purpose. The aim of this study is to develop new Fe3O4-Fe nanoparticles with a core-shell structure with antitumor activity in vitro. Nanoparticles containing from 5 % to 90 % iron were synthesized, and a systematic study of the structural, textural, charge, morphological, and magnetic properties of nanoparticles, as well as their in vitro activity against the MCF-7 and HeLa tumor lines, was carried out. Methods. Fe3O4-Fe nanoparticles were obtained by electric explosion of an iron wire in a mixture of gases: argon and oxygen. The mass fraction of the components was regulated by varying the ratio of the components of the gas mixture. The physicochemical properties of nanoparticles were studied using X-ray phase analysis, thermal desorption of nitrogen, transmission electron microscopy, and microelectrophoresis. Antitumor activity was studied using the MTT test against HeLa and MCF-7 cell lines. Results. As a result of the electric explosion of an iron wire in an argon + oxygen gas mixture containing oxygen in the range of 1 – 5 vol. %, Fe3O4-Fe NPs with 5 – 90 % wt. Fe3O4, respectively. The study of the physicochemical properties of nanoparticles showed that the zeta potential does not depend on the content of Fe3O4 in NPs and is -30 mV. The change in the specific surface area and the average particle size passes through a maximum at the content of Fe3O4 W=20 %, which can be explained by the mechanism of oxide phase formation during an electric explosion. Using the MTT test, it was found that nanoparticles containing 5 wt. Fe3O4, in the presence of which, at a concentration of 1 mg/ml, the number of living cells decreased to 16 % relative to the control. Conclusion. In this work, we have shown for the first time that Fe3O4-Fe NPS in the concentration range of 50–100 µg/mL can be used as an antitumor agent. The ability to control the magnetic properties of NPs can be used to target a specific area of tumor tissue using an external magnetic field, and the established relationship between the magnetic moment and the activity of NPs in relation to the MCF-7 cell line has great prospects for clinical application.

Underwater Shock Wave Generated by Exploding Wire Ignited Energetic Materials and its Applications in Reservoir Stimulation

The combination of energetic material (EM) and electrical wire explosion (EWE) is an efficient and economical method to generate strong shock waves (SWs). The idea resembles the exploding bridge-wire (EBW) detonator, but in this case, the EWE operates with much higher electrical energy storage, and the EMs of much lower sensitivity can be directly ignited, which provides a practical compromise among limited energy storage, strong SWs, and safe usage of explosives. The hybrid load based on EWE ignited EMs has been successfully applied for reservoir stimulation in exploitation of both conventional and unconventional oil/gas resources. In this brief review, we summarize the EWE characteristics, SW characteristics, ignition mechanism, and engineering applications of this hybrid load, and give suggestions for future research directions.

Fe-Ag pseudo-alloys obtained by wire electric explosion, ball milling and spark plasma sintering

• Fe-Ag pseudo-alloys formed by wire electric explosion and spark plasma sintering. • WEE powder was ball-milled to improve its structural uniformity. • In pseudo-alloy formed from milled powder, silver grains were 300-500 nm in size. • Material sintered from ball-milled powder showed a higher microhardness. • Porous silver with a uniform structure was obtained from sintered material. Structural features of Fe-25 wt.% Ag pseudo-alloys obtained by spark plasma sintering of the product of wire electric explosion (WEE) and the product of WEE processed by ball milling were comparatively investigated for the first time. In the sintered pseudo-alloy produced from the WEE powder, inclusions of iron 5-10 μm were found in the Fe-Ag composite matrix. The size of silver grains was of the order of 1 μm and 300-500 nm in the sintered materials produced from the WEE powder and ball-milled powder, respectively. The pseudo-alloys sintered from the ball-milled powder showed a higher microhardness than the material sintered from the WEE powder. Porous silver obtained from the pseudo-alloy sintered from the WEE powder by selectively dissolving iron showed micrometer-sized pores in the former places of iron particles of those sizes. In contrast, porous silver obtained from the pseudo-alloy sintered from the ball-milled powder had a uniform structure free from large pores.

The optical diagnosis of electrical wire explosion under a microsecond current pulse.

Electrical wire explosions have many applications in scientific research and industry. Optical diagnosis is a powerful method to clarify the evolutionary process of such explosions. In this paper, an experimental platform was established to diagnose the optical radiation of electrical wire explosions. A low-jitter trigatron switch and its trigger generator were designed to ensure accurate synchronization. The spatial-temporal evolution process and the self-emission spectrum of electrical explosion plasmas from different wires (copper and tantalum) were obtained and analyzed. The optical diagnosis results indicated that the electrical explosion of copper wire was mainly characterized by the inhomogeneity of partial ionization and the rapid expansion of the discharge channel. The spectrum in the early discharge stage of the copper wire electrical explosion was a continuum, and most of the self-radiation spectral lines belonged to Cu I or Cu II. At the later stage of the plasma dissipation process, the continuous spectrum gradually transformed into a line spectrum. The development of the tantalum wire discharge channel was relatively uniform, and the plasma was mainly established in the gas-liquid mixed phase channel of the tantalum wire. The self-emission spectrum of the tantalum wire was always continuous, and the absorption process of line spectrum radiation was distinct.

Electroexplosive synthesis of composite ZnO/ZnFe2O4/Zn nanoparticles with photocatalytic and antibacterial activity

Composite ZnO/ZnFe2O4/Zn nanoparticles with zinc oxide content 25–75 at % were synthesized for the first time by electrical explosion of two twisted wires in one stage in an oxygen-containing atmosphere. The morphology, phase composition, textural characteristics, optical properties and antibacterial activity against antibiotic-resistant bacteria MRSA have been investigated. The sample with the highest ZnO content (70 at.% ZnO) demonstrates significant degradation of the MB. Degradation reached 72 % within 120 min of the experiment in the visible light irradiation that was higher than that of ZnO nanoparticles produced by electric explosion of zinc wire in oxygen. Nanoparticles had enhanced antibacterial activity against MRSA which is based on reactive oxygen species generation. The ZnO/ZnFe2O4/Zn nanoparticles have prospects for widespread use in the fields of water purification and biomedicine as promising antimicrobial agents.

Powder Injection Molding of Ti-Al-W Nano/Micro Bimodal Powders: Structure, Phase Composition and Oxidation Kinetics

Products from the materials of the Ti-Al system are difficult to manufacture. This often restricts the use of such materials despite their outstanding properties. Some of the promising methods for manufacturing products, which allows working with materials of the Ti-Al system, are powder injection molding (PIM) and material extrusion additive manufacturing (MEAM) technologies. In the present study, powder composites Ti-48Al-4W with different powder size distribution, obtained by the electric explosion of wire (EEW) method, were investigated. The powder was used in PIM technology to produce bulk samples. After polymer debinding, PIM samples were sintered in a vacuum and using hot isostatic pressing (HIP) at the same temperatures and isothermal holding times. The results show the influence of size distribution and sintering method on the structure, phase composition, mechanical properties and oxidation resistance of pre-sintered PIM samples. It is found that both the size distribution and sintering method affect the mechanical properties. The smaller the particle size of the powder in the material, the greater the resistance to oxidation of such samples.

Formation and Antibacterial Activity of AlOOH/Ag Composite Coating on Macroporous α-Al2O3 Ceramics

In this study, the modification of macroporous α-Al2O3 ceramics with AlOOH nanostructures impregnated with silver particles is carried out using bicomponent Al/Ag nanoparticles obtained by the simultaneous electrical explosion of Al and Ag wires. Nanoparticle suspension impregnation of porous ceramics followed by oxidation with water is shown to lead to the formation of a continuous AlOOH nanosheet coating on the ceramic surface, with silver releasing on the surface of nanosheets in the form of individual particles sized 5–30 nm. Modified with AlOOH/Ag nanostructures, macroporous α-Al2O3 pellets with a diameter of 11 mm and a thickness of 5 mm show 100% efficiency for water purification from bacteria with a concentration of 105 CFU/mL for 7.5 min at a flow rate of 6.7 mL/min.

Two-dimensional simulation of microsecond-timescale underwater electrical explosion of a copper wire

Underwater electrical wire explosion (UEWE) is an efficient source of underwater shock waves (SWs). In order to efficiently simulate the interaction between the UEWE SW and structures, a coupled model that includes the electric circuit, the exploding wire and the surrounding water is established based on user-subroutines provided by the commercial explicit dynamics software ANSYS AUTODYN. The modeling starts from room temperature by using the tabular wide-range metal equation of state (EOS) and conductivity data. Experimental validation is performed with copper wires exploded by a μs-timescale pulsed discharge. The numerical results show satisfactory consistency with experiments in terms of the current and voltage waveforms, the wire expansion trajectory, the evolution of SW front, the interaction between SW and electrodes and the SW pressure profiles. The main discrepancy lies in the SW amplitude that is ∼20% higher in the calculation and the possible reasons are discussed in detail. Based on this approach and with proper modifications to the metal EOS and conductivity data, the interaction between UEWE SWs and structures can be efficiently modeled in 2D and 3D for practical applications.