The nonlinear traveling wave vibration of rotating ferromagnetic functionally graded(FG)cylindrical shells under multi-physics fields is investigated.Grounded in the Kirchhoff-Love thin shell theory,the geometric nonl...The nonlinear traveling wave vibration of rotating ferromagnetic functionally graded(FG)cylindrical shells under multi-physics fields is investigated.Grounded in the Kirchhoff-Love thin shell theory,the geometric nonlinearity is incorporated into the model,and the constitutive equations are derived.The physical parameters of functionally graded materials(FGMs),which exhibit continuous variation across the thickness gradient,are of particular interest.The nonlinear magneto-thermoelastic governing equations are derived in accord with Hamilton's principle.The nonlinear partial differential equations are discretized with the Galerkin method,and the analytical expression of traveling wave frequencies is derived with an approximate method.The accuracy of the proposed method is validated through the comparison with the results from the literature and numerical solutions.Finally,the visualization analyses are conducted to examine the effects of key parameters on the traveling wave frequencies.The results show that the factors including the power-law index,temperature,magnetic field intensity,and rotating speed have the coupling effects with respect to the nonlinear vibration behavior.展开更多
To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dime...To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.展开更多
Reducing coke use is an effective measure to reduce carbon emission and energy consumption in the blast furnace(BF)ironmaking.Essentially,BF is a high-temperature moving bed reactor,where complex physical transformati...Reducing coke use is an effective measure to reduce carbon emission and energy consumption in the blast furnace(BF)ironmaking.Essentially,BF is a high-temperature moving bed reactor,where complex physical transformations coupled with complicated reactions occur.This makes it challenging to investigate the factors determining BF performance with the conventional method.A multi-physical field coupling mathematical model of BF was thus developed to describe its mass and heat transfer as well as its intrinsic reactions.Then,the proposed model was validated with the production data.Under coupling conditions,influences of dominating reactions on BF performance(temperature distribution,gas distribution,iron formation reaction,and direct reduction degree)were revealed.The results indicated that coke combustion,indirect reduction,and direct reduction of iron ore mainly took place nearby the shaft tuyere,cohesive zone,and dripping zone,respectively.Besides,the rate of coke solution loss reaction was increased with the rising coke porosity in the cohesive zone.Considering the effect of coke porosity on the efficiency and stability of BF,the coke porosity of 0.42 was regarded as a reasonable value.展开更多
This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite elem...This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite element model of GMM smart component in electric, magnetic, and mechanical fields by step computation to optimize the design of GMM smart com-ponent. The proposed model is implemented by using COMSOL multi-physics V3.2a. The effects of the smart component on the deformation and the system resonance frequencies are studied. The results calculated by the model are in excellent agreement (relative errors are below 10%) with the experimental values.展开更多
A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet dur...A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet during the charging and discharging processes.The coupled problem is resolved by means of the finite element method(FEM)for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system.The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet.Moreover,a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process,while a forward azimuthal current and a tensile hoop stress are observed during the discharging process.The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists.Therefore,it brings forth significant Joule heat,causing a temperature rise and a uniform distribution of this heat in the coil turns.Accordingly,a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil.It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil,while a discharging will not.The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.展开更多
The smelting reduction process of the ilmenite in an electric arc furnace(EAF)is a commonly used technology for producing titanium slag in the world.It has particular significance to analyze the velocity-temperature-e...The smelting reduction process of the ilmenite in an electric arc furnace(EAF)is a commonly used technology for producing titanium slag in the world.It has particular significance to analyze the velocity-temperature-electromagnetics multi-physical field in an EAF for improving its productivity and reducing energy consumption.A transient three-dimensional mathematical model was developed to characterize the flow,heat transfer,and electromagnetic behavior in a titanium slag EAF.For describing the electromagnetic field and its effects on velocity and temperature distribution in the furnace,magnetohydrodynamic equations and conservation equations for mass,momentum,and energy were solved simultaneously by compiling the user-defined function program.The numerical model was verified by comparing with the literature data.The results indicate that the Lorentz force is the main driving force of the velocity and temperature distribution.Moreover,the influence of input current and location of electrodes on the multi-physical field distribution was also investigated.It is found that the appropriate range of input current and diameter of pitch circle are about 30,000 A and 3000-3500 mm,respectively.The mathematical model established can characterize the multi-physical field more accu-rately than before,which can provide valuable guidance for the operation improvement and design optimization of the EAF for producing titanium slag.展开更多
Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the inf...Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the influence of induction pump settings on the related delivery speed,in this study,a numerical model for coupled electromagnetic and flow field effects is introduced and used to simulate liquid metal lithium flow in the induction pump.The effects of current intensity,frequency,coil turns and coil winding size on the velocity of the working fluid are analyzed.It is shown that the first three parameters have a significant impact,while changes in the coil turns have a negligible influence.The maximum increase in working fluid velocity within the pump for the parameter combination investigated in this paper is approximately 618%.As the frequency is increased from 20 to 60 Hz,the maximum increase in the mean flow rate of the working fluid is approximately 241%.These research findings are intended to support the design and optimization of these devices.展开更多
This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat fl...This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the bearings.By changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through experi-ments.This research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.展开更多
The tribovoltaic effect represents a newly discovered semiconductor effect for mechanical-to-electrical energy conversion.However,the semiconductor interfaces are typically susceptible to environmental multi-physics f...The tribovoltaic effect represents a newly discovered semiconductor effect for mechanical-to-electrical energy conversion.However,the semiconductor interfaces are typically susceptible to environmental multi-physics fields,such as illumination,temperature,and humidity,which can affect the energy conversion process of the tribovoltaic effect.In this review,we provide a comprehensive overview of the current research status of the environmental multi-physics coupled tribovoltaic effect for energy harvesting.We summarize the electrical output characteristics of tribovoltaic nanogenerators(TVNGs)in various physical field environments and the impact mechanisms of these fields on electrical performance,demonstrating their ability to capture and convert a wide range of mechanical energies,including wind,rain,waves,and illumination.We discuss the fundamental principles underlying these devices,their potential applications,and the key chal-lenges and opportunities for future development.This review deepens our understanding of the energy harvesting mechanism of the tribovoltaic effect in multi-physics coupling.Adopting a multi-physics energy harvesting strategy not only broadens the scope and efficiency of energy harvesting but also drives the development of novel energy conversion devices,proposing fresh ideas for future innovations in sustainable energy solutions.展开更多
With rapid advancements in physics and particle medicine,the domestic accelerator industry has grown rapidly.During the 12th Five-Year Plan period,the Institute of Modern Physics of the Chinese Academy of Sciences too...With rapid advancements in physics and particle medicine,the domestic accelerator industry has grown rapidly.During the 12th Five-Year Plan period,the Institute of Modern Physics of the Chinese Academy of Sciences took on a plurality of accelerator projects.Nevertheless,the stability of the coupler,a crucial system within the cavities of accelerators,has encountered certain difficulties.The alumina ceramics,which constitute the core component of the coupler,are increasingly prone to breakage and solder joint failures due to their inferior environmental adaptability,inadequate mechanical properties,and high gas emissions.Conversely,with the advancements in medical technology and materials science,zirconia ceramics have emerged as a prospective remedy for these problems.This type of ceramic is highly esteemed for its outstanding environmental adaptability,remarkable mechanical properties,and excellent high-temperature resistance,exhibiting extraordinary value in dental applications.This study investigates the use of zirconia ceramics in a 162.5 MHz 3-1/8"standard ceramic window,combining experimental data with finite element RF simulations and multi-physics analysis.A new coupler featuring a zirconia ceramic window was tested on a Quarter-Wave Resonator,demonstrating excellent alignment between electromagnetic simulations and measurement results.This reveals the substantial application potential and practical worth of the zirconia ceramic material in the context of accelerators.展开更多
This paper presents a comprehensive review on recent development and research conducted in domestic and international underground laboratories. We first introduce the differences in three environments—surface, mounta...This paper presents a comprehensive review on recent development and research conducted in domestic and international underground laboratories. We first introduce the differences in three environments—surface, mountain tunnel cavities and underground coal mine tunnels—by examining cosmic ray background, ambient noises related to gravity and seismic measurement, and electromagnetic noises in magnetic and magnetotelluric measurements. We highlight potential misuse of the term Underground Lab or Deep Underground Lab when describing observations in different physical fields. We introduce unique features of underground coal mine tunnels in China, such as large spaces, ultra-quiet conditions, and ultra-clean environments. When comparing with mountain tunnel cavities and borehole observations, coal mine tunnel observations have superior long-term stability and high precision. Through observations and comparisons of multi-physic fields at surface and the deep underground, we find that the higher SNR seismic observations conducted in deep underground tunnels in coal mines are beneficial to improve velocity tomography of the solid earth. The gravity observation with a Superconducting Quantum Interference Device(SQUID) makes it possibly to capture slow earthquake, which has not been observed previously in the Chinese mainland. SQUID magnetic observations can detect fluctuations as weak as femto-Tesla(fT), enabling us to explore the attenuation of Schumann Resonance down to the solid Earth. This opens opportunities to investigate the connections between the Earth's magnetic field and the interactions within the human brain and heart. To improve the precision of quantum measurement,we should consider the possible effects of weak magnetic disturbances in deep underground environments. Finally, we discuss the importance of deep underground laboratories, observing facilities and techniques deployed in these laboratories, and their possible connection with respect to “deep space” and “deep ocean” exploration, emphasizing the need for focused research on various scientific challenges. We hope to encourage greater attention to deep underground laboratory and high-precision scientific observation.展开更多
Skin panels on supersonic vehicles are subjected to aero-thermo-acoustic loads,resulting in a well-known multi-physics dynamic problem.The high-frequency dynamic response of these panels significantly impacts the stru...Skin panels on supersonic vehicles are subjected to aero-thermo-acoustic loads,resulting in a well-known multi-physics dynamic problem.The high-frequency dynamic response of these panels significantly impacts the structural safety of supersonic vehicles,but it has been rarely investigated.Given that existing methods are inefficient for high-frequency dynamic analysis in multi-physics fields,the present work addresses this challenge by proposing a Stochastic Energy Finite Element Method(SEFEM).SEFEM uses energy density instead of displacement to describe the dynamic response,thereby significantly enhancing its efficiency.In SEFEM,the effects of aerodynamic and thermal loads on the energy propagation characteristics are studied analytically and incorporated into the energy density governing equation.These effects are also considered when calculating the input power generated by the acoustic load,and two effective approaches named Frequency Response Function Method(FRFM)and Mechanical Impedance Method(MIM)are developed accordingly and integrated into SEFEM.The good accuracy,applicability,and high efficiency of the proposed SEFEM are demonstrated through numerical simulations performed on a two-dimensional panel under aero-thermoacoustic loads.Additionally,the effects and underlying mechanisms of aero-thermo-acoustic loads on the high-frequency response are explored.This work not only presents an efficient approach for predicting high-frequency dynamic response of panels subjected to aero-thermo-acoustic loads,but also provides insights into the high-frequency dynamic characteristics in multi-physics fields.展开更多
We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework em...We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.展开更多
Obtaining a uniform interface temperature field plays a crucial role in the interface bonding quality of bimetal compound rolls.Therefore,this study proposes an improved electroslag remelting cladding(ESRC)process usi...Obtaining a uniform interface temperature field plays a crucial role in the interface bonding quality of bimetal compound rolls.Therefore,this study proposes an improved electroslag remelting cladding(ESRC)process using an external magnetic field to improve the uniformity of the interface temperature of compound rolls.The improved ESRC comprises a conventional ESRC circuit and an external coil circuit.A comprehensive 3D model,including multi-physics fields,is proposed to study the effect of external magnetic fields on the multi-phys-ics fields and interface temperature uniformity.The simulated results demonstrate that the nonuniform Joule heat and flow fields cause a non-uniform interface temperature in the conventional ESRC.As for the improved ESRC,the magnetic flux density(B_(coil))along the z-axis is pro-duced by an anticlockwise current of the external coil.The rotating Lorentz force is generated from the interaction between the radial current and axial B_(coil).Therefore,the slag pool flows clockwise,which enhances circumferential effective thermal conductivity.As a result,the uniformity of the temperature field and interface temperature improve.In addition,the magnetic flux density and rotational speed of the simulated results are in good agreement with those of the experimental results,which verifies the accuracy of the improved ESRC model.Therefore,an improved ESRC is efficient for industrial production of the compound roll with a uniform interface bonding quality.展开更多
A numerical model coupled with a multi-physical field based on dynamic formation of slag skin is established.After validation by comparing the experimental and simulation results of depth of metal pool,slag skin thick...A numerical model coupled with a multi-physical field based on dynamic formation of slag skin is established.After validation by comparing the experimental and simulation results of depth of metal pool,slag skin thickness and melt rate,it is utilized to investigate the effect of melt current on the coupled multi-physical field,slag skin thickness,metal pool depth and the heat flow distribution during electroslag remelting(ESR)Inconel 625 solidification process.The results showed that with the increase in the melt current,the velocities of ESR system and the temperature of metal pool increased,whereas the highest temperature of slag bath firstly decreased and then increased.With the increase in the melt current,the slag skin thickness,metal pool depth and melt rate increased.Furthermore,the characteristics of the heat flow distribution and the effect of melt current on the heat flow distribution were analysed.展开更多
Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises si...Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises significantly and even burns.It becomes critical to ensure electromagnetic absorption performance while minimizing temperature rise.Here,we systematically study the coupling mechanism between the electromagnetic field and the temperature field when the absorbing material is irradiated by electromagnetic waves.We find out the influence of the constitutive parameters of the absorbing materials(including uniform and non-uniform)on the temperature distribution.Finally,through a smart design,we achieve better absorption and lower temperature simultaneously.The accuracy of the model is affirmed as simulation results aligned with theoretical analysis.This work provides a new avenue to control the temperature distribution of absorbing materials.展开更多
Split pulsed magnets are widely employed in high temperature superconducting(HTS)motor armature winding as magnetizing coils to implement in-situ pulsed field magnetization(PFM)for HTS field pole magnets.We have desig...Split pulsed magnets are widely employed in high temperature superconducting(HTS)motor armature winding as magnetizing coils to implement in-situ pulsed field magnetization(PFM)for HTS field pole magnets.We have designed and developed a compact and portable split pulsed magnet,that balances a peak central magnetic field of nearly 7 T and a rise time of 24 ms,making it particularly suitable for PFM of HTS materials at lower temperatures.Single and two-step PFM experiments of HTS GdBa_(2)Cu_(3)O_(7-δ)(GdBCO)bulk in different temperature ranges are conducted and the maximum trapped fields B_(t)are observed to be>3 T in the 40-50 K temperature range and nearly 4 T at 30 K in a 30 mm diameter GdBCO bulk.The trapped field results validate the excellent PFM ability of this designed split pulsed magnet and indicate a high trapped field(close to 4 T)can also be obtained in a coreless double armature.Moreover,multi-physical field responses of the split pulsed magnet during discharge are analyzed by a 3D field-circuit coupling model,which manifests that the split pulsed magnet is in a stable and safe operating state even under the highest charge voltage.Finally,this study may provide a novel clue for the development of coreless HTS bulk motors and suggest that HTS coreless motors can maintain a high air gap magnetic field while avoiding losses and thrust or torque fluctuations caused by iron core saturation under high magnetic fields.展开更多
Particle coating is a very important step in many industrial production processes as the particle coating layers may fix surfaces with unique advantages. Given the limitation and disadvantages of the existing simulati...Particle coating is a very important step in many industrial production processes as the particle coating layers may fix surfaces with unique advantages. Given the limitation and disadvantages of the existing simulation methods, a coupled CFD–DEM–CVD multi-physical field model for particle-coating simulations has been established taking into account the velocity field, temperature field, concentration field, and deposition model. In this model, gas behavior and chemical reactions are simulated in the CFD frame based on the conservation laws of mass, momentum, and energy. The particle behavior is simulated in the DEM frame based on the gas–solid interphase force model and contact force model. The deposition behavior is simulated in the CVD frame based on the particle movement–adhesion–deposition model. The coupled model can be implemented in Fluent-EDEM software with their user definition function and application programming interface. The particle coating process involving the pyrolysis of acetylene was investigated, and the effect of bed temperature and inlet gas velocity on deposition rate and coating efficiency were investigated based on the proposed model with adjustable deposition coefficients. Both the average deposition layer mass and the average deposition layer thickness were found to be proportional to the elapsed time and increased at the rate of about 1.05 × 10^-2 mg/s and 3.45 × 10^-4 mm/s, respectively, setting the inlet gas velocity to 11 m/s and bed temperature to 1680 K. A higher temperature and larger inlet gas velocity lead to a larger deposition rate, but the coating efficiency decreases because of limits imposed by the chemical reaction. At a bed temperature of 1280 K, the average deposition rate is 7.40 × 10?3 mg/s when the inlet gas velocity is set to 11 m/s, which is about double the deposition rate when the inlet gas velocity is set as 5 m/s. The proposed model can provide some guidance for the operating conditions and parameters design of the spouted bed in actual coating settings and can also be further developed as a basic model of mechanisms to integrate detailed information across multiple scales.展开更多
Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are con...Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are conducive to the realization of long-term and high-precision observation of multi-physical fields,thus enabling the solution of a series of geoscience problems.In the Panyidong Coal Mine,where there are extensive underground tunnels at the depth of 848 m below sea level,we carried out the first deep-underground geophysical observations,including radioactivity,gravity,magnetic,magnetotelluric,background vibration and six-component seismic observations.We concluded from these measurements that(1)the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders of magnitude weaker than that in the surface observation environment;(2)the underground electric field is obviously weaker than the surface electric field,and the relatively high frequency of the underground field,greater than 1 Hz,is more than two orders of magnitude weaker than that of the surface electric field;the east-west magnetic field underground is approximately the same as that at the surface;the relatively high-frequency north-south magnetic field underground,below 10 Hz,is at least one order of magnitude lower than that at the surface,showing that the underground has a clean electromagnetic environment;(3)in addition to the highfrequency and single-frequency noises introduced by underground human activities,the deep underground space has a significantly lower background vibration noise than the surface,which is very beneficial to the detection of weak earthquake and gravity signals;and(4)the underground roadway support system built with ferromagnetic material interferes the geomagnetic field.We also found that for deep observation in the“ultra-quiet and ultra-clean”environment,the existing geophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well as data cleaning problems,such as the effective separation of the signal and noise of deep observation data.It is also urgent to interpret and comprehensively utilize these high-precision multi-physics observation data.展开更多
The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the sa...The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the safety of the pipeline operation and the quality of the petroleum products.Thus,it is necessary to study the methods of removing these trapped particles from pipelines.At present,the most common way to remove these solid particle impurities is pigging oil pipelines periodically by utilizing the mechanical pigging method,while the frequent pigging operation will increase the cost and risk of pipeline operation.It is very convenient and economical to remove the accumulated particles out from the pipeline by oil stream,which can be named Hydraulic Pigging Method(HPM).However,the behavior mechanism of particle in flowing oil is still unclear.This motivates the present research on the particles flushed out by the flowing oil.A numerical model governing the trapped particles displacement from the elbow of an inclined oil pipeline is established in the Euler-Lagrangian framework.The simulation is achieved via CFD coupling with DEM.The CFD method is employed to solving the continuous phase flow,while the discrete particle phase is tracked by the DEM.The numerical model is first validated by comparison with results taken from the published literature.From the simulation results,it is observed that the oil stream,carrier phase,can only flush out the solid particles in a certain diameter range under the given operation conditions,and the particles whose diameter beyond that diameter range will cannot be removed out from the pipeline.The influence of the pipe inclined angle,the oil bulk velocity and the particle diameter on the particle migration characteristics is examined in detail.Furthermore,in order to enhance the efficiency of HPM,an Enhanced Hydraulic Pigging Method based on Multi-Physical Field Collaboration(EHPM-MPFC)is also proposed in the present work.The EHPM-MPFC is validated for having high pigging efficiency via the comparison of the migration characteristics of particles during the EHPM-MPFC and HPM process.The present results can provide the guidance to the HPM operation of products pipelines.展开更多
基金supported by the National Natural Science Foundation of China(No.12172321)。
文摘The nonlinear traveling wave vibration of rotating ferromagnetic functionally graded(FG)cylindrical shells under multi-physics fields is investigated.Grounded in the Kirchhoff-Love thin shell theory,the geometric nonlinearity is incorporated into the model,and the constitutive equations are derived.The physical parameters of functionally graded materials(FGMs),which exhibit continuous variation across the thickness gradient,are of particular interest.The nonlinear magneto-thermoelastic governing equations are derived in accord with Hamilton's principle.The nonlinear partial differential equations are discretized with the Galerkin method,and the analytical expression of traveling wave frequencies is derived with an approximate method.The accuracy of the proposed method is validated through the comparison with the results from the literature and numerical solutions.Finally,the visualization analyses are conducted to examine the effects of key parameters on the traveling wave frequencies.The results show that the factors including the power-law index,temperature,magnetic field intensity,and rotating speed have the coupling effects with respect to the nonlinear vibration behavior.
文摘To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage.In this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried out.Various test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of rail.Combining the simulation results and experimental data,the damage condition of the contact surface is analyzed.
基金supported by the National Natural Science Foundation of China(Grant Nos.22278001 and 21776002)the Natural Science Foundation of Anhui Provincial Education Department(No.KJ2021A0407)+1 种基金the Natural Science Foundation of Anhui Province(Grant No.2008085QB87)Anhui Provincial Postdoctoral Science Foundation(No.2021B538).
文摘Reducing coke use is an effective measure to reduce carbon emission and energy consumption in the blast furnace(BF)ironmaking.Essentially,BF is a high-temperature moving bed reactor,where complex physical transformations coupled with complicated reactions occur.This makes it challenging to investigate the factors determining BF performance with the conventional method.A multi-physical field coupling mathematical model of BF was thus developed to describe its mass and heat transfer as well as its intrinsic reactions.Then,the proposed model was validated with the production data.Under coupling conditions,influences of dominating reactions on BF performance(temperature distribution,gas distribution,iron formation reaction,and direct reduction degree)were revealed.The results indicated that coke combustion,indirect reduction,and direct reduction of iron ore mainly took place nearby the shaft tuyere,cohesive zone,and dripping zone,respectively.Besides,the rate of coke solution loss reaction was increased with the rising coke porosity in the cohesive zone.Considering the effect of coke porosity on the efficiency and stability of BF,the coke porosity of 0.42 was regarded as a reasonable value.
基金supported by the National Natural Science Foundation of China (No. 50575205)the Hi-Tech Research and Development (863) Program of China (Nos. 2006AA04Z233 and 2007AA04Z101)+1 种基金the Doctoral Foundation of Ministry of Education of China (No. 20070335204)the Zhejiang Provincial Natural Science Foundation of China (No. Z1080537)
文摘This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite element model of GMM smart component in electric, magnetic, and mechanical fields by step computation to optimize the design of GMM smart com-ponent. The proposed model is implemented by using COMSOL multi-physics V3.2a. The effects of the smart component on the deformation and the system resonance frequencies are studied. The results calculated by the model are in excellent agreement (relative errors are below 10%) with the experimental values.
基金the National Natural Science Foundation of China(Nos.11932008 and 11672120)the Fundamental Research Funds for the Central Universities of China(No.lzujbky-2022-kb01)。
文摘A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet during the charging and discharging processes.The coupled problem is resolved by means of the finite element method(FEM)for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system.The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet.Moreover,a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process,while a forward azimuthal current and a tensile hoop stress are observed during the discharging process.The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists.Therefore,it brings forth significant Joule heat,causing a temperature rise and a uniform distribution of this heat in the coil turns.Accordingly,a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil.It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil,while a discharging will not.The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.
基金supported by the National Natural Science Foundation of China(No.U2003215).
文摘The smelting reduction process of the ilmenite in an electric arc furnace(EAF)is a commonly used technology for producing titanium slag in the world.It has particular significance to analyze the velocity-temperature-electromagnetics multi-physical field in an EAF for improving its productivity and reducing energy consumption.A transient three-dimensional mathematical model was developed to characterize the flow,heat transfer,and electromagnetic behavior in a titanium slag EAF.For describing the electromagnetic field and its effects on velocity and temperature distribution in the furnace,magnetohydrodynamic equations and conservation equations for mass,momentum,and energy were solved simultaneously by compiling the user-defined function program.The numerical model was verified by comparing with the literature data.The results indicate that the Lorentz force is the main driving force of the velocity and temperature distribution.Moreover,the influence of input current and location of electrodes on the multi-physical field distribution was also investigated.It is found that the appropriate range of input current and diameter of pitch circle are about 30,000 A and 3000-3500 mm,respectively.The mathematical model established can characterize the multi-physical field more accu-rately than before,which can provide valuable guidance for the operation improvement and design optimization of the EAF for producing titanium slag.
文摘Magnetohydrodynamic(MHD)induction pumps are contactless pumps able to withstand harsh environments.The rate of fluid flow through the pump directly affects the efficiency and stability of the device.To explore the influence of induction pump settings on the related delivery speed,in this study,a numerical model for coupled electromagnetic and flow field effects is introduced and used to simulate liquid metal lithium flow in the induction pump.The effects of current intensity,frequency,coil turns and coil winding size on the velocity of the working fluid are analyzed.It is shown that the first three parameters have a significant impact,while changes in the coil turns have a negligible influence.The maximum increase in working fluid velocity within the pump for the parameter combination investigated in this paper is approximately 618%.As the frequency is increased from 20 to 60 Hz,the maximum increase in the mean flow rate of the working fluid is approximately 241%.These research findings are intended to support the design and optimization of these devices.
基金the National Natural Science Foundation of China(No.52075468)the Natural Science Foundation of Hebei Province(No.E2020203052)+1 种基金the Key Scientific Research Projects of North China University of Technology(No.ZD-YG-202306-23)the Tangshan Science and Technology Project(No.23130201E).
文摘This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the bearings.By changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through experi-ments.This research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.
基金supported by the Beijing Natural Science Foundation(3232019)the National Natural Science Foundation of China(62104020 and 52450006).
文摘The tribovoltaic effect represents a newly discovered semiconductor effect for mechanical-to-electrical energy conversion.However,the semiconductor interfaces are typically susceptible to environmental multi-physics fields,such as illumination,temperature,and humidity,which can affect the energy conversion process of the tribovoltaic effect.In this review,we provide a comprehensive overview of the current research status of the environmental multi-physics coupled tribovoltaic effect for energy harvesting.We summarize the electrical output characteristics of tribovoltaic nanogenerators(TVNGs)in various physical field environments and the impact mechanisms of these fields on electrical performance,demonstrating their ability to capture and convert a wide range of mechanical energies,including wind,rain,waves,and illumination.We discuss the fundamental principles underlying these devices,their potential applications,and the key chal-lenges and opportunities for future development.This review deepens our understanding of the energy harvesting mechanism of the tribovoltaic effect in multi-physics coupling.Adopting a multi-physics energy harvesting strategy not only broadens the scope and efficiency of energy harvesting but also drives the development of novel energy conversion devices,proposing fresh ideas for future innovations in sustainable energy solutions.
文摘With rapid advancements in physics and particle medicine,the domestic accelerator industry has grown rapidly.During the 12th Five-Year Plan period,the Institute of Modern Physics of the Chinese Academy of Sciences took on a plurality of accelerator projects.Nevertheless,the stability of the coupler,a crucial system within the cavities of accelerators,has encountered certain difficulties.The alumina ceramics,which constitute the core component of the coupler,are increasingly prone to breakage and solder joint failures due to their inferior environmental adaptability,inadequate mechanical properties,and high gas emissions.Conversely,with the advancements in medical technology and materials science,zirconia ceramics have emerged as a prospective remedy for these problems.This type of ceramic is highly esteemed for its outstanding environmental adaptability,remarkable mechanical properties,and excellent high-temperature resistance,exhibiting extraordinary value in dental applications.This study investigates the use of zirconia ceramics in a 162.5 MHz 3-1/8"standard ceramic window,combining experimental data with finite element RF simulations and multi-physics analysis.A new coupler featuring a zirconia ceramic window was tested on a Quarter-Wave Resonator,demonstrating excellent alignment between electromagnetic simulations and measurement results.This reveals the substantial application potential and practical worth of the zirconia ceramic material in the context of accelerators.
基金supported by the National Science and Technology Major Project (Grant No. 2024ZD1002700)the National Natural Science Foundation of China (Grant Nos. 62127815, 42150201, U1839208)。
文摘This paper presents a comprehensive review on recent development and research conducted in domestic and international underground laboratories. We first introduce the differences in three environments—surface, mountain tunnel cavities and underground coal mine tunnels—by examining cosmic ray background, ambient noises related to gravity and seismic measurement, and electromagnetic noises in magnetic and magnetotelluric measurements. We highlight potential misuse of the term Underground Lab or Deep Underground Lab when describing observations in different physical fields. We introduce unique features of underground coal mine tunnels in China, such as large spaces, ultra-quiet conditions, and ultra-clean environments. When comparing with mountain tunnel cavities and borehole observations, coal mine tunnel observations have superior long-term stability and high precision. Through observations and comparisons of multi-physic fields at surface and the deep underground, we find that the higher SNR seismic observations conducted in deep underground tunnels in coal mines are beneficial to improve velocity tomography of the solid earth. The gravity observation with a Superconducting Quantum Interference Device(SQUID) makes it possibly to capture slow earthquake, which has not been observed previously in the Chinese mainland. SQUID magnetic observations can detect fluctuations as weak as femto-Tesla(fT), enabling us to explore the attenuation of Schumann Resonance down to the solid Earth. This opens opportunities to investigate the connections between the Earth's magnetic field and the interactions within the human brain and heart. To improve the precision of quantum measurement,we should consider the possible effects of weak magnetic disturbances in deep underground environments. Finally, we discuss the importance of deep underground laboratories, observing facilities and techniques deployed in these laboratories, and their possible connection with respect to “deep space” and “deep ocean” exploration, emphasizing the need for focused research on various scientific challenges. We hope to encourage greater attention to deep underground laboratory and high-precision scientific observation.
基金financially supported by the National Natural Science Foundation of China(Nos.12302228 and 12372170)。
文摘Skin panels on supersonic vehicles are subjected to aero-thermo-acoustic loads,resulting in a well-known multi-physics dynamic problem.The high-frequency dynamic response of these panels significantly impacts the structural safety of supersonic vehicles,but it has been rarely investigated.Given that existing methods are inefficient for high-frequency dynamic analysis in multi-physics fields,the present work addresses this challenge by proposing a Stochastic Energy Finite Element Method(SEFEM).SEFEM uses energy density instead of displacement to describe the dynamic response,thereby significantly enhancing its efficiency.In SEFEM,the effects of aerodynamic and thermal loads on the energy propagation characteristics are studied analytically and incorporated into the energy density governing equation.These effects are also considered when calculating the input power generated by the acoustic load,and two effective approaches named Frequency Response Function Method(FRFM)and Mechanical Impedance Method(MIM)are developed accordingly and integrated into SEFEM.The good accuracy,applicability,and high efficiency of the proposed SEFEM are demonstrated through numerical simulations performed on a two-dimensional panel under aero-thermoacoustic loads.Additionally,the effects and underlying mechanisms of aero-thermo-acoustic loads on the high-frequency response are explored.This work not only presents an efficient approach for predicting high-frequency dynamic response of panels subjected to aero-thermo-acoustic loads,but also provides insights into the high-frequency dynamic characteristics in multi-physics fields.
基金supported by the Major National Science and Technology Infrastructure(No.2208-000000-04-01249628)the Shanghai Science and Technology Commission(No.21DZ1206500)。
文摘We present a hybrid smoothed particle magnetohydrodynamics(SPMHD)code integrating smoothed particle hydrodynamics(SPH)and finite element methods(FEM)to simulate coupled fluid-electromagnetic phenomena.The framework employs SPH for fluid dynamics,addressing large deformations,shocks,and plasma behavior,while FEM resolves electromagnetic fields via Maxwell's equations for magnetic vector and electric scalar potentials,ensuring divergence-free conditions and global current density calculations in conductive region.Operator splitting method couples these modules,enabling real-time integration of magnetic,electric,thermal,and fluid fields.Benchmark tests validate the code against analytical solutions and existing models,including blow-by instability simulations that demonstrate the method's accuracy in capturing fluid-magnetic interactions.Designed for 3D applications,SPMHD offers robust scalability across multiprocessor architectures,establishing it as a versatile tool for plasma physics research.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51874084 and 52174303)the Fundamental Research Funds for the Central Universities of China(No.N2125026).
文摘Obtaining a uniform interface temperature field plays a crucial role in the interface bonding quality of bimetal compound rolls.Therefore,this study proposes an improved electroslag remelting cladding(ESRC)process using an external magnetic field to improve the uniformity of the interface temperature of compound rolls.The improved ESRC comprises a conventional ESRC circuit and an external coil circuit.A comprehensive 3D model,including multi-physics fields,is proposed to study the effect of external magnetic fields on the multi-phys-ics fields and interface temperature uniformity.The simulated results demonstrate that the nonuniform Joule heat and flow fields cause a non-uniform interface temperature in the conventional ESRC.As for the improved ESRC,the magnetic flux density(B_(coil))along the z-axis is pro-duced by an anticlockwise current of the external coil.The rotating Lorentz force is generated from the interaction between the radial current and axial B_(coil).Therefore,the slag pool flows clockwise,which enhances circumferential effective thermal conductivity.As a result,the uniformity of the temperature field and interface temperature improve.In addition,the magnetic flux density and rotational speed of the simulated results are in good agreement with those of the experimental results,which verifies the accuracy of the improved ESRC model.Therefore,an improved ESRC is efficient for industrial production of the compound roll with a uniform interface bonding quality.
基金supported by Special funding project for research and development of key core technologies and common technologies in Shanxi Province(20201102017)supported by National Natural Science Foundations of China(Grant No.51874085 and 52274323)the Fundamental Research Funds for the Central Universities(Grant No.N2125030).
文摘A numerical model coupled with a multi-physical field based on dynamic formation of slag skin is established.After validation by comparing the experimental and simulation results of depth of metal pool,slag skin thickness and melt rate,it is utilized to investigate the effect of melt current on the coupled multi-physical field,slag skin thickness,metal pool depth and the heat flow distribution during electroslag remelting(ESR)Inconel 625 solidification process.The results showed that with the increase in the melt current,the velocities of ESR system and the temperature of metal pool increased,whereas the highest temperature of slag bath firstly decreased and then increased.With the increase in the melt current,the slag skin thickness,metal pool depth and melt rate increased.Furthermore,the characteristics of the heat flow distribution and the effect of melt current on the heat flow distribution were analysed.
文摘Electromagnetic absorbing materials may convert electromagnetic energy into heat energy and dissipate it.However,in a high-power electromagnetic radiation environment,the temperature of the absorbing material rises significantly and even burns.It becomes critical to ensure electromagnetic absorption performance while minimizing temperature rise.Here,we systematically study the coupling mechanism between the electromagnetic field and the temperature field when the absorbing material is irradiated by electromagnetic waves.We find out the influence of the constitutive parameters of the absorbing materials(including uniform and non-uniform)on the temperature distribution.Finally,through a smart design,we achieve better absorption and lower temperature simultaneously.The accuracy of the model is affirmed as simulation results aligned with theoretical analysis.This work provides a new avenue to control the temperature distribution of absorbing materials.
基金supported by the National Natural Science Foundation of China(52377021).
文摘Split pulsed magnets are widely employed in high temperature superconducting(HTS)motor armature winding as magnetizing coils to implement in-situ pulsed field magnetization(PFM)for HTS field pole magnets.We have designed and developed a compact and portable split pulsed magnet,that balances a peak central magnetic field of nearly 7 T and a rise time of 24 ms,making it particularly suitable for PFM of HTS materials at lower temperatures.Single and two-step PFM experiments of HTS GdBa_(2)Cu_(3)O_(7-δ)(GdBCO)bulk in different temperature ranges are conducted and the maximum trapped fields B_(t)are observed to be>3 T in the 40-50 K temperature range and nearly 4 T at 30 K in a 30 mm diameter GdBCO bulk.The trapped field results validate the excellent PFM ability of this designed split pulsed magnet and indicate a high trapped field(close to 4 T)can also be obtained in a coreless double armature.Moreover,multi-physical field responses of the split pulsed magnet during discharge are analyzed by a 3D field-circuit coupling model,which manifests that the split pulsed magnet is in a stable and safe operating state even under the highest charge voltage.Finally,this study may provide a novel clue for the development of coreless HTS bulk motors and suggest that HTS coreless motors can maintain a high air gap magnetic field while avoiding losses and thrust or torque fluctuations caused by iron core saturation under high magnetic fields.
基金National Natural Science Foundation of China (Grant Nos: 91634113, 21306097) for the financial support provided.
文摘Particle coating is a very important step in many industrial production processes as the particle coating layers may fix surfaces with unique advantages. Given the limitation and disadvantages of the existing simulation methods, a coupled CFD–DEM–CVD multi-physical field model for particle-coating simulations has been established taking into account the velocity field, temperature field, concentration field, and deposition model. In this model, gas behavior and chemical reactions are simulated in the CFD frame based on the conservation laws of mass, momentum, and energy. The particle behavior is simulated in the DEM frame based on the gas–solid interphase force model and contact force model. The deposition behavior is simulated in the CVD frame based on the particle movement–adhesion–deposition model. The coupled model can be implemented in Fluent-EDEM software with their user definition function and application programming interface. The particle coating process involving the pyrolysis of acetylene was investigated, and the effect of bed temperature and inlet gas velocity on deposition rate and coating efficiency were investigated based on the proposed model with adjustable deposition coefficients. Both the average deposition layer mass and the average deposition layer thickness were found to be proportional to the elapsed time and increased at the rate of about 1.05 × 10^-2 mg/s and 3.45 × 10^-4 mm/s, respectively, setting the inlet gas velocity to 11 m/s and bed temperature to 1680 K. A higher temperature and larger inlet gas velocity lead to a larger deposition rate, but the coating efficiency decreases because of limits imposed by the chemical reaction. At a bed temperature of 1280 K, the average deposition rate is 7.40 × 10?3 mg/s when the inlet gas velocity is set to 11 m/s, which is about double the deposition rate when the inlet gas velocity is set as 5 m/s. The proposed model can provide some guidance for the operating conditions and parameters design of the spouted bed in actual coating settings and can also be further developed as a basic model of mechanisms to integrate detailed information across multiple scales.
基金supported by the National Natural Science Foundation of China (Grant Nos.62127815,42150201,U1839208)
文摘Compared with the surface,the deep environment has the advantages of allowing“super-quiet and ultra-clean”-geophysical field observation with low vibration noise and little electromagnetic interference,which are conducive to the realization of long-term and high-precision observation of multi-physical fields,thus enabling the solution of a series of geoscience problems.In the Panyidong Coal Mine,where there are extensive underground tunnels at the depth of 848 m below sea level,we carried out the first deep-underground geophysical observations,including radioactivity,gravity,magnetic,magnetotelluric,background vibration and six-component seismic observations.We concluded from these measurements that(1)the background of deep subsurface gravity noise in the long-period frequency band less than 2 Hz is nearly two orders of magnitude weaker than that in the surface observation environment;(2)the underground electric field is obviously weaker than the surface electric field,and the relatively high frequency of the underground field,greater than 1 Hz,is more than two orders of magnitude weaker than that of the surface electric field;the east-west magnetic field underground is approximately the same as that at the surface;the relatively high-frequency north-south magnetic field underground,below 10 Hz,is at least one order of magnitude lower than that at the surface,showing that the underground has a clean electromagnetic environment;(3)in addition to the highfrequency and single-frequency noises introduced by underground human activities,the deep underground space has a significantly lower background vibration noise than the surface,which is very beneficial to the detection of weak earthquake and gravity signals;and(4)the underground roadway support system built with ferromagnetic material interferes the geomagnetic field.We also found that for deep observation in the“ultra-quiet and ultra-clean”environment,the existing geophysical equipment and observation technology have problems of poor adaptability and insufficient precision as well as data cleaning problems,such as the effective separation of the signal and noise of deep observation data.It is also urgent to interpret and comprehensively utilize these high-precision multi-physics observation data.
基金This work is part of the program of“The research on the optimization and supply-side reliability of oil product logistics system(No.51874325)”,which is funded by the National Natural Science Foundation of China.
文摘The solid particle impurities generated by pipe wall corrosion might deposit at the elbow of hilly pipelines during the production shutdown of oil pipelines.These solid particle impurities will seriously affect the safety of the pipeline operation and the quality of the petroleum products.Thus,it is necessary to study the methods of removing these trapped particles from pipelines.At present,the most common way to remove these solid particle impurities is pigging oil pipelines periodically by utilizing the mechanical pigging method,while the frequent pigging operation will increase the cost and risk of pipeline operation.It is very convenient and economical to remove the accumulated particles out from the pipeline by oil stream,which can be named Hydraulic Pigging Method(HPM).However,the behavior mechanism of particle in flowing oil is still unclear.This motivates the present research on the particles flushed out by the flowing oil.A numerical model governing the trapped particles displacement from the elbow of an inclined oil pipeline is established in the Euler-Lagrangian framework.The simulation is achieved via CFD coupling with DEM.The CFD method is employed to solving the continuous phase flow,while the discrete particle phase is tracked by the DEM.The numerical model is first validated by comparison with results taken from the published literature.From the simulation results,it is observed that the oil stream,carrier phase,can only flush out the solid particles in a certain diameter range under the given operation conditions,and the particles whose diameter beyond that diameter range will cannot be removed out from the pipeline.The influence of the pipe inclined angle,the oil bulk velocity and the particle diameter on the particle migration characteristics is examined in detail.Furthermore,in order to enhance the efficiency of HPM,an Enhanced Hydraulic Pigging Method based on Multi-Physical Field Collaboration(EHPM-MPFC)is also proposed in the present work.The EHPM-MPFC is validated for having high pigging efficiency via the comparison of the migration characteristics of particles during the EHPM-MPFC and HPM process.The present results can provide the guidance to the HPM operation of products pipelines.
