In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wir...In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wire electrical explosion is divided into four stages. Stage Ⅰ： the wire is in solid state. Stage Ⅱ： the melting stage. Stage Ⅲ： the wire melts completely and the initial plasma forms. Stage IV： the core and corona expand separately. The thermodynamic calculation is applied before the wire melts completely in stages Ⅰ and Ⅱ. In stage Ⅲ, a one-dimensional magnetohydrodynamics model comes into play until the instant when the voltage collapse occurs. The temperature, density, and velocity, which are derived from the magnetohydrodynamics calculation, are averaged over the distribution area. The averaged parameters are taken as the initial conditions for stage Ⅳ in which a simplified magnetohydrodynamics model is applied. A wide-range semi-empirical equation of state, which is established based on the Thomas-Fermi-Kirzhnits model, is constructed to describe the phase transition from solid state to plasma state. The initial plasma formation and the phenomenon of current transfer in the electrical explosion of aluminum wire are investigated using the computational model. Experiments of electrical explosion of aluminum wires are carried out to verify this model. Simulation results are also compared with experimental results of the electrical explosion of copper wire.展开更多
Investigating the characteristics of synchronous electrical explosions of multiple exploding foil initiators(EFI)in the same circuit,a four-point series-connected EFI circuit utilizing flexible flat cables was designe...Investigating the characteristics of synchronous electrical explosions of multiple exploding foil initiators(EFI)in the same circuit,a four-point series-connected EFI circuit utilizing flexible flat cables was designed to analyze the electrical explosion characteristics.Loop current and terminal voltages of each EFI were recorded to characterize the multi-point series-connected EFI explosion.The effects of voltage,capacitance,and loop length on the response time,energy deposition,and energy utilization efficiency of the multi-point series-connected EFI were explored.Based on the FIRESET model,a mathematical model for the multi-point series-connected EFI explosion was developed,and the influence of initial resistivity on the peak voltage during electrical explosion was quantitatively analyzed.Results indicate that the primary factor influencing the response time is the conduction performance of the switch,while the synchronization deviation is minimally affected by variations in voltage and capacitance.At an inter-electrode spacing of 50 mm,within the voltage range of 1,500–3,000 V and capacitance range of 0.22–1.5μF,the minimum and maximum synchronization deviations of the four-point EFI were 2 ns and 11 ns,respectively.As input energy increases,the deposited energy of the EFI rises,but the overall energy utilization efficiency decreases.The computational results of the proposed model align well with the experimental data.Furthermore,higher initial resistivity in the series-connected circuit corresponds to a higher peak voltage during electrical explosion.This work elucidates the characteristics of multi-point series-connected EFI explosions,offering valuable insights for the design of multi-point EFI circuits.展开更多
A small electrical explosion of wire （EEW） setup for nanopowder production is constructed. It consists of a low inductance capacitor bank of 2 μF–4 μF typically charged to 8 kV–30 kV, a triggered gas switch, and...A small electrical explosion of wire （EEW） setup for nanopowder production is constructed. It consists of a low inductance capacitor bank of 2 μF–4 μF typically charged to 8 kV–30 kV, a triggered gas switch, and a production chamber housing the exploding wire load and ambient gas. With the EEW device, nanosize powders of titanium oxides, titanium nitrides, copper oxides, and zinc oxides are successfully synthesized. The average particle size of synthesized powders under different experimental conditions is in a range of 20nm–80nm. The pressure of ambient gas or wire vapor can strongly affect the average particle size. The lower the pressure, the smaller the particle size is. For wire material with relatively high resistivity, such as titanium, whose deposited energy Wd is often less than sublimation energy W s due to the flashover breakdown along the wire prematurely ending the Joule heating process, the synthesized particle size of titanium oxides or titanium nitrides increases with overheat coefficient k （k = W d /Ws ） increasing.展开更多
Based on the low inductance technology and parallel-plate transmission principle,an experimental apparatus of small-scale slapper initiating primary high explosives driven by electrical explosion is designed and estab...Based on the low inductance technology and parallel-plate transmission principle,an experimental apparatus of small-scale slapper initiating primary high explosives driven by electrical explosion is designed and established.The problem of instantaneously and continuously measuring the velocity of the small-scale slapper is successfully solved by using the technique of laser interference.Compared with the results published on the literatures at home and abroad,data of the experimental and the numerical simulation shown in this paper are more proper to reflect the physical process of electrical explosion driving slapper.One-dimensional numerical simulation of electrical explosion driving slapper is done using the hydrodynamic code.The experimental results are consistent with the computed ones by introducing a power correction factor.In the end,the introduced power correction factor is discussed.展开更多
Electrical wire explosion is a promising method for the preparation of metal nanopowder, but the properties of metal nanopowder are affected by the second discharge process of electrical wire explosion. The second dis...Electrical wire explosion is a promising method for the preparation of metal nanopowder, but the properties of metal nanopowder are affected by the second discharge process of electrical wire explosion. The second discharge characteristics of aluminum wire electrical ex- plosion under variant argon pressures were studied in a RLC discharge circuit. The results show that the curve of the second discharge voltages versus the pressure presents a U-shape. To clarify the roles of aluminum vapor and argon in the process of the second discharge, a spectrograph and a high speed framing camera were used to study the radiation spectrum and spatial distribution of the electrical explosion plasma. It is observed that argon participates in the second discharge process under low pressure. A discharge channel develops along the surface of the aluminum vapor. Under higher pressure, a second discharge takes place in the aluminum vapor and the discharge channel is inside the aluminum vapor.展开更多
Wire electrical explosion may result in the existence of micro-sized large particles in powders while current injection ways may influence the size and content of micro-sized large particles. Therefore, two kinds of e...Wire electrical explosion may result in the existence of micro-sized large particles in powders while current injection ways may influence the size and content of micro-sized large particles. Therefore, two kinds of electrical explosion devices with different electrodes by gas discharge were designed in this paper. The pole-board electrodes and the cone electrodes were used respectively for studying copper wire electrical explosion process. The current and voltage data were measured with the Rogowski coil and high voltage probe. The results show that the pulverizing process of electrical explosion is more efficient when the wire electrode current density injected into the cone electrodes is approximately twice as much as the pole-board electrodes. The content of micro-sized large particles is the least among the products of the electrical explosion, when the total deposition energy of the wire prior to vaporization stage is 2. 5 times larger than that of the theoretical value of the completed vaporization.展开更多
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 exp...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-1and 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 of2600 K-2500 K.The characteristic temperature for the formation of Al nanoparticles is~2520K,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.展开更多
This work deals with an experimental study of a Cu planar wire array(PWA)in air and water under the stored energy 300-1200 J.A single Cu wire is adopted as a controlled trial.Four configurations of PWA and a wire with...This work deals with an experimental study of a Cu planar wire array(PWA)in air and water under the stored energy 300-1200 J.A single Cu wire is adopted as a controlled trial.Four configurations of PWA and a wire with the same mass(cross-section area)but the different specific surface areas(15-223 cm^(2)g^(-1))are exploded.The transient process is analyzed using high-speed photography in combination with the results of optical emission and discharge.Discharge characteristics revealed that PWA always has a higher electric power peak,early but higher voltage peak,as well as faster vaporization and ionization process than the single-wire case.Two to three times stronger optical emission could be obtained when replacing the single-wire with PWA,indicating a higher energy-density state is reached.Phenomenologically,in both air and water,single-wire load tends to develop a transverse stratified structure,while PWA is dominated by the uneven energy deposition among wires.Finally,the synchronism and uniformity of the PWA explosion are discussed.展开更多
Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization ...Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.展开更多
In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning e...In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS),showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions.In particular,pure FeO(OH)nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV.Analysis of discharge current and resistive voltage data indicate that the high energy input induced bystrong plasma discharge at high charging voltage is a key factor to form FeO(OH).This study presents a one-step method to synthesize FeO(OH)nanoparticles using electric explosion of iron wire.展开更多
The directional explosion behavior of finite volume water confined within nanochannels holds considerable potential for applications in precision nanofabrication and bioengineering.However,precise control of nanoscale...The directional explosion behavior of finite volume water confined within nanochannels holds considerable potential for applications in precision nanofabrication and bioengineering.However,precise control of nanoscale mass transfer remains challenging in nanofluidics.This study examined the dynamic evolution of water clusters confined within a single-end-opened carbon nanotube(CNT)under pulsed electric field(EF)excitation,with a particular focus on the structural reorganization of hydrogen bond(H-bond)networks and dipole orientation realignment.Molecular dynamics simulations reveal that under the influence of pulsed EF,the confinedwatermolecules undergo cooperative restructuring to maximize hydrogen bond formation through four independent motions during deformation,such as waving,spinning,axial slipping,and radial migration.In this process,the dynamic fracture and recombination of the hydrogen bond network generate an instantaneous high pressure,and drive a unidirectional explosion along the CNT axis.A smaller CNT diameter or a reduced water volume under the same EF conditions leads to a stronger explosion.In contrast,in a wider CNT,the water cluster expands axially and forms a cylindrical shell whose thickness gradually decreases as the axial expansion slows.These insights offer precise control strategies for nanofluidic systems in nanofabrication or bioengineering applications,where finite volume water serves as a programmable nanoscale energy transfer medium.展开更多
The effect of the electric field with different intensity on explosion wave pressure and flame propagation velocity of gas explosion was experimentally studied, and the effect of electric field on gas explosion and it...The effect of the electric field with different intensity on explosion wave pressure and flame propagation velocity of gas explosion was experimentally studied, and the effect of electric field on gas explosion and its propagation was theoretically analyzed from heat transportation, mass transportation, and reaction process of gas explosion. The results show that the electric field can affect gas explosion by enhancing explosion intensity and explosion pressure, thus increasing flame velocity. The electric field can offer energy to the gas explosion reaction; the effect of the electric field on gas explosion increases with the increase of electric field intensity. The electric field can increase mass transfer action, heat transfer action, convection effects, diffusion coefficient, and the reaction system entropy, which make the turbulence of gas explosion in electric field increase; therefore, the electric field can improve flame combustion velocity and flame propagation velocity, release more energy, increase shock wave energy, and then promote the gas explosion and its propagation.展开更多
The results of experiments on electroexplosion titanic foil in water solutions of salts of uranium are presented in this paper. It is shown, that as a result of electroexplosion occurs appreciable (to 20%) distortion ...The results of experiments on electroexplosion titanic foil in water solutions of salts of uranium are presented in this paper. It is shown, that as a result of electroexplosion occurs appreciable (to 20%) distortion of an initial isotope parity of uranium. In the most solution parts, observable isotope distortion occurs in favour of enrichment by 235U. At the moment of electroexplosion it was not observed an appreciable stream of the neutrons. By means of Cs label and by methods by α, β, γ-spectrometry and mass-spectrometry it have been shown, that isotope distortion occurs at the expense of non-uniform “disappearance” of both isotopes from a solution. The isotope distortion leads to infringement of the 234Th secular equilibrium in the uranyl solution. The equilibrium infringement between the 234Th and 234mPa, i.e. within the proper thorium decay chain, was observed also. The assumption about that the effects are caused of low-energy nuclear reactions at the moment of electroexplosion is suggested.展开更多
Gas explosions in coal mine goafs are associated with the roof rock fracturing.An experimental system was established to investigate the potential for electrical ignition induced by sandstone fracturing.The electrical...Gas explosions in coal mine goafs are associated with the roof rock fracturing.An experimental system was established to investigate the potential for electrical ignition induced by sandstone fracturing.The electrical responses,luminescent emissions,and ignition characteristics during tensile and compressive failure of sandstones were analyzed in methane/air premixed gas environments.Results indicate that the application of mechanical loading induces the emergence of electrical signals on rock surfaces and in the surrounding atmosphere.This phenomenon is attributed to the generation,accumulation,and subsequent release of free charges during the deformation and fracture within the sandstone.Compressive failure proved to be more conducive to free charge generation than tensile failure,owing to more crack connections.Furthermore,a precipitous increase in surface and external voltages was observed during complete fracturing,a consequence of electron emission from crack tips within the rock structure.Moreover,the ionization induces luminous emissions owing to the collision of energetic electrons released from gas molecules in methane/air mixtures.A strong positive correlation(R2=0.9429)was identified between luminescence intensity and the magnitude of electrical discharge resulting from rock fracture.Notably,such discharge by rock fracturing can be capable of igniting the premixed gas,particularly when the quartz content exceeds 61%.Piezoelectric effects and crack propagation are crucial mechanisms in the causal chain of the charge generation,discharge,and ionization triggered by rock fractures.Based on the above laboratory results,electric ignition of the transient roof fracturing caused by stress mutations can serve as a new potential ignition source for gas explosions in the goaf.These results offer new insights into the prevention and control of gas explosions.展开更多
基金Project supported by the National Science Foundation of China(Grant Nos.51322706,51237006,and 51325705)the Program for New Century Excellent Talents in University,China(Grant No.NCET-11-0428)the Fundamental Research Funds for the Central Universities,China
文摘In this paper, a computational model is constructed to investigate the phenomenon of the initial plasma formation and current transfer in the single-wire electrical explosion in a vacuum. The process of the single-wire electrical explosion is divided into four stages. Stage Ⅰ： the wire is in solid state. Stage Ⅱ： the melting stage. Stage Ⅲ： the wire melts completely and the initial plasma forms. Stage IV： the core and corona expand separately. The thermodynamic calculation is applied before the wire melts completely in stages Ⅰ and Ⅱ. In stage Ⅲ, a one-dimensional magnetohydrodynamics model comes into play until the instant when the voltage collapse occurs. The temperature, density, and velocity, which are derived from the magnetohydrodynamics calculation, are averaged over the distribution area. The averaged parameters are taken as the initial conditions for stage Ⅳ in which a simplified magnetohydrodynamics model is applied. A wide-range semi-empirical equation of state, which is established based on the Thomas-Fermi-Kirzhnits model, is constructed to describe the phase transition from solid state to plasma state. The initial plasma formation and the phenomenon of current transfer in the electrical explosion of aluminum wire are investigated using the computational model. Experiments of electrical explosion of aluminum wires are carried out to verify this model. Simulation results are also compared with experimental results of the electrical explosion of copper wire.
文摘Investigating the characteristics of synchronous electrical explosions of multiple exploding foil initiators(EFI)in the same circuit,a four-point series-connected EFI circuit utilizing flexible flat cables was designed to analyze the electrical explosion characteristics.Loop current and terminal voltages of each EFI were recorded to characterize the multi-point series-connected EFI explosion.The effects of voltage,capacitance,and loop length on the response time,energy deposition,and energy utilization efficiency of the multi-point series-connected EFI were explored.Based on the FIRESET model,a mathematical model for the multi-point series-connected EFI explosion was developed,and the influence of initial resistivity on the peak voltage during electrical explosion was quantitatively analyzed.Results indicate that the primary factor influencing the response time is the conduction performance of the switch,while the synchronization deviation is minimally affected by variations in voltage and capacitance.At an inter-electrode spacing of 50 mm,within the voltage range of 1,500–3,000 V and capacitance range of 0.22–1.5μF,the minimum and maximum synchronization deviations of the four-point EFI were 2 ns and 11 ns,respectively.As input energy increases,the deposited energy of the EFI rises,but the overall energy utilization efficiency decreases.The computational results of the proposed model align well with the experimental data.Furthermore,higher initial resistivity in the series-connected circuit corresponds to a higher peak voltage during electrical explosion.This work elucidates the characteristics of multi-point series-connected EFI explosions,offering valuable insights for the design of multi-point EFI circuits.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50677034)the State Key Laboratory of Control and Simulation of Power System and Generation Equipment, China (Grant No. SKLD11M04)the State Key Laboratory of Electrical Insulation and Power Equipment, China (Grant No. EIPE12201)
文摘A small electrical explosion of wire （EEW） setup for nanopowder production is constructed. It consists of a low inductance capacitor bank of 2 μF–4 μF typically charged to 8 kV–30 kV, a triggered gas switch, and a production chamber housing the exploding wire load and ambient gas. With the EEW device, nanosize powders of titanium oxides, titanium nitrides, copper oxides, and zinc oxides are successfully synthesized. The average particle size of synthesized powders under different experimental conditions is in a range of 20nm–80nm. The pressure of ambient gas or wire vapor can strongly affect the average particle size. The lower the pressure, the smaller the particle size is. For wire material with relatively high resistivity, such as titanium, whose deposited energy Wd is often less than sublimation energy W s due to the flashover breakdown along the wire prematurely ending the Joule heating process, the synthesized particle size of titanium oxides or titanium nitrides increases with overheat coefficient k （k = W d /Ws ） increasing.
基金Sponsored by the Foundation of Institute of Fluid Physics of China Academy of Engineering Physics
文摘Based on the low inductance technology and parallel-plate transmission principle,an experimental apparatus of small-scale slapper initiating primary high explosives driven by electrical explosion is designed and established.The problem of instantaneously and continuously measuring the velocity of the small-scale slapper is successfully solved by using the technique of laser interference.Compared with the results published on the literatures at home and abroad,data of the experimental and the numerical simulation shown in this paper are more proper to reflect the physical process of electrical explosion driving slapper.One-dimensional numerical simulation of electrical explosion driving slapper is done using the hydrodynamic code.The experimental results are consistent with the computed ones by introducing a power correction factor.In the end,the introduced power correction factor is discussed.
基金supported by the Fundamental Research Funds for the Central Universities of China
文摘Electrical wire explosion is a promising method for the preparation of metal nanopowder, but the properties of metal nanopowder are affected by the second discharge process of electrical wire explosion. The second discharge characteristics of aluminum wire electrical ex- plosion under variant argon pressures were studied in a RLC discharge circuit. The results show that the curve of the second discharge voltages versus the pressure presents a U-shape. To clarify the roles of aluminum vapor and argon in the process of the second discharge, a spectrograph and a high speed framing camera were used to study the radiation spectrum and spatial distribution of the electrical explosion plasma. It is observed that argon participates in the second discharge process under low pressure. A discharge channel develops along the surface of the aluminum vapor. Under higher pressure, a second discharge takes place in the aluminum vapor and the discharge channel is inside the aluminum vapor.
基金This research was supported by National Natural Science Foundation of China （No. 51061011 ）.
文摘Wire electrical explosion may result in the existence of micro-sized large particles in powders while current injection ways may influence the size and content of micro-sized large particles. Therefore, two kinds of electrical explosion devices with different electrodes by gas discharge were designed in this paper. The pole-board electrodes and the cone electrodes were used respectively for studying copper wire electrical explosion process. The current and voltage data were measured with the Rogowski coil and high voltage probe. The results show that the pulverizing process of electrical explosion is more efficient when the wire electrode current density injected into the cone electrodes is approximately twice as much as the pole-board electrodes. The content of micro-sized large particles is the least among the products of the electrical explosion, when the total deposition energy of the wire prior to vaporization stage is 2. 5 times larger than that of the theoretical value of the completed vaporization.
文摘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-1and 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 of2600 K-2500 K.The characteristic temperature for the formation of Al nanoparticles is~2520K,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.
基金supported in part by National Natural Science Foundation of China(No.51907007)Natural Science Foundation of Beijing(No.3212034)+1 种基金State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE20204)State Key Laboratory of Advanced Electromagnetic Engineering and Technology(No.AEET 2019KF006)。
文摘This work deals with an experimental study of a Cu planar wire array(PWA)in air and water under the stored energy 300-1200 J.A single Cu wire is adopted as a controlled trial.Four configurations of PWA and a wire with the same mass(cross-section area)but the different specific surface areas(15-223 cm^(2)g^(-1))are exploded.The transient process is analyzed using high-speed photography in combination with the results of optical emission and discharge.Discharge characteristics revealed that PWA always has a higher electric power peak,early but higher voltage peak,as well as faster vaporization and ionization process than the single-wire case.Two to three times stronger optical emission could be obtained when replacing the single-wire with PWA,indicating a higher energy-density state is reached.Phenomenologically,in both air and water,single-wire load tends to develop a transverse stratified structure,while PWA is dominated by the uneven energy deposition among wires.Finally,the synchronism and uniformity of the PWA explosion are discussed.
基金National Natural Science Foundation of China(Grant No.11872013)for supporting this project.
文摘Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.
基金This research was supported by National Natural Science Foundation of China(Grant No.11702283).
文摘In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage.The as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS),showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions.In particular,pure FeO(OH)nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV.Analysis of discharge current and resistive voltage data indicate that the high energy input induced bystrong plasma discharge at high charging voltage is a key factor to form FeO(OH).This study presents a one-step method to synthesize FeO(OH)nanoparticles using electric explosion of iron wire.
基金The Start-up Research Fund from Shenzhen,the Natural Science Foundation of Guangdong(Grant Nos.2024A1515010821,2025A1515011727)the Shenzhen Development and ReformCommission(Grant No.XMHT20220103004).
文摘The directional explosion behavior of finite volume water confined within nanochannels holds considerable potential for applications in precision nanofabrication and bioengineering.However,precise control of nanoscale mass transfer remains challenging in nanofluidics.This study examined the dynamic evolution of water clusters confined within a single-end-opened carbon nanotube(CNT)under pulsed electric field(EF)excitation,with a particular focus on the structural reorganization of hydrogen bond(H-bond)networks and dipole orientation realignment.Molecular dynamics simulations reveal that under the influence of pulsed EF,the confinedwatermolecules undergo cooperative restructuring to maximize hydrogen bond formation through four independent motions during deformation,such as waving,spinning,axial slipping,and radial migration.In this process,the dynamic fracture and recombination of the hydrogen bond network generate an instantaneous high pressure,and drive a unidirectional explosion along the CNT axis.A smaller CNT diameter or a reduced water volume under the same EF conditions leads to a stronger explosion.In contrast,in a wider CNT,the water cluster expands axially and forms a cylindrical shell whose thickness gradually decreases as the axial expansion slows.These insights offer precise control strategies for nanofluidic systems in nanofabrication or bioengineering applications,where finite volume water serves as a programmable nanoscale energy transfer medium.
基金Supported by the National Natural Science Foundation of China （51004048） the Research Fund of State Key Laboratory of Coal Resources and Safe Mining, CUMT（09KF05）+2 种基金 the Post-Doctoral Science Foundation of China （20100470998） the Scientific Research Fund of Hunan Provincial Education Department（09C409） the State Key Base Development Plan（2005cb221506）
文摘The effect of the electric field with different intensity on explosion wave pressure and flame propagation velocity of gas explosion was experimentally studied, and the effect of electric field on gas explosion and its propagation was theoretically analyzed from heat transportation, mass transportation, and reaction process of gas explosion. The results show that the electric field can affect gas explosion by enhancing explosion intensity and explosion pressure, thus increasing flame velocity. The electric field can offer energy to the gas explosion reaction; the effect of the electric field on gas explosion increases with the increase of electric field intensity. The electric field can increase mass transfer action, heat transfer action, convection effects, diffusion coefficient, and the reaction system entropy, which make the turbulence of gas explosion in electric field increase; therefore, the electric field can improve flame combustion velocity and flame propagation velocity, release more energy, increase shock wave energy, and then promote the gas explosion and its propagation.
文摘The results of experiments on electroexplosion titanic foil in water solutions of salts of uranium are presented in this paper. It is shown, that as a result of electroexplosion occurs appreciable (to 20%) distortion of an initial isotope parity of uranium. In the most solution parts, observable isotope distortion occurs in favour of enrichment by 235U. At the moment of electroexplosion it was not observed an appreciable stream of the neutrons. By means of Cs label and by methods by α, β, γ-spectrometry and mass-spectrometry it have been shown, that isotope distortion occurs at the expense of non-uniform “disappearance” of both isotopes from a solution. The isotope distortion leads to infringement of the 234Th secular equilibrium in the uranyl solution. The equilibrium infringement between the 234Th and 234mPa, i.e. within the proper thorium decay chain, was observed also. The assumption about that the effects are caused of low-energy nuclear reactions at the moment of electroexplosion is suggested.
基金supported by the National Natural Science Foundation of China(Nos.52130411,52174219 and 52174220)the Natural Science Foundation of Jiangsu Province(No.BK20240104)the Fundamental Research Funds for the Central Universities(No.2024-11044).
文摘Gas explosions in coal mine goafs are associated with the roof rock fracturing.An experimental system was established to investigate the potential for electrical ignition induced by sandstone fracturing.The electrical responses,luminescent emissions,and ignition characteristics during tensile and compressive failure of sandstones were analyzed in methane/air premixed gas environments.Results indicate that the application of mechanical loading induces the emergence of electrical signals on rock surfaces and in the surrounding atmosphere.This phenomenon is attributed to the generation,accumulation,and subsequent release of free charges during the deformation and fracture within the sandstone.Compressive failure proved to be more conducive to free charge generation than tensile failure,owing to more crack connections.Furthermore,a precipitous increase in surface and external voltages was observed during complete fracturing,a consequence of electron emission from crack tips within the rock structure.Moreover,the ionization induces luminous emissions owing to the collision of energetic electrons released from gas molecules in methane/air mixtures.A strong positive correlation(R2=0.9429)was identified between luminescence intensity and the magnitude of electrical discharge resulting from rock fracture.Notably,such discharge by rock fracturing can be capable of igniting the premixed gas,particularly when the quartz content exceeds 61%.Piezoelectric effects and crack propagation are crucial mechanisms in the causal chain of the charge generation,discharge,and ionization triggered by rock fractures.Based on the above laboratory results,electric ignition of the transient roof fracturing caused by stress mutations can serve as a new potential ignition source for gas explosions in the goaf.These results offer new insights into the prevention and control of gas explosions.
