To meet the demands of continuous stream-line for component production in the thixo-forming industry, billet heating should be of high quality and in a controllable way. A 4-step inductive heating strategy for aluminu...To meet the demands of continuous stream-line for component production in the thixo-forming industry, billet heating should be of high quality and in a controllable way. A 4-step inductive heating strategy for aluminum alloy A356 was performed. Thixotropic testing and microstructure analysis showed that a homogenous temperature distribution was achieved after temperature-power-time optimization. Theoretical analysis was given concerning the thermal conductivity and heat capacity of A356 between conventional and semisolid casting microstructures. The experimental results show that the optimized 4-step strategy could be the best strategy for billet heating during the thixo-forming of aluminum alloy A356.展开更多
We examine a convective dissipation-free heat transfer in melts under the action of a stationary component of electromagnetic body force induced by frequency-modulated travelling magnetic field.The influence of MHD pa...We examine a convective dissipation-free heat transfer in melts under the action of a stationary component of electromagnetic body force induced by frequency-modulated travelling magnetic field.The influence of MHD parameters of turbulent flow on the transfer process is studied.展开更多
In the anticorrosive coating line of a welded tube plant, the current status and existing problems of the medium-frequency induction heating equipment were discussed.Partial renovations of the power control cabinet ha...In the anticorrosive coating line of a welded tube plant, the current status and existing problems of the medium-frequency induction heating equipment were discussed.Partial renovations of the power control cabinet have been conducted.Parameters such as the DC current, DC voltage, intermediate frequency power, heating temperature, and the positioning signal at the pipe end were collected.A data acquisition and processing system, which can process data according to user needs and provide convenient data processing functions, has been developed using LabVIEW software.This system has been successfully applied in the coating line for the automatic control of high-power induction heating equipment, production management, and digital steel tube and/or digital delivery.展开更多
To efficiently remove perfluorooctanoic acid(PFOA),we developed a composite of magnetic Fe_(3)O_(4)nanocrystals and MIL-101(an iron-based metal organic framework).Because of its high surface area,porous structure,and ...To efficiently remove perfluorooctanoic acid(PFOA),we developed a composite of magnetic Fe_(3)O_(4)nanocrystals and MIL-101(an iron-based metal organic framework).Because of its high surface area,porous structure,and complexation between PFOA as confirmed by experimental results and density functional theory simulation,the magnetic composite showed a Langmuir adsorption capacity of 415 mg/g in the presence of various groundwater components,and thus adsorbed PFOA at environment-relevant concentration within 20 min.The catalyst loaded with PFOA can then be magnetically separated from the synthetic groundwater.This adsorption step concentrated PFOA near MIL-101 and resulted in a fast decomposition rate in the decomposition step,where MIL-101 served as an efficient Fenton agent due to its abundant Fe^(3+)/Fe^(2+)sites.Meanwhile,the alternative magnetic field was introduced to change the production pathway of reactive oxygen species and superoxide radical anions were produced,which was critical for PFOA degradation.In addition,the inductive heating effect heat the magnetic particles to445 K through an in-situ approach,which thus further accelerated Fenton reactions rate.In addition,and achieved a complete degradation of PFOA within 30 min.This newly developed Fenton catalyst demonstrates advantages over conventionally heterogeneous and homogeneous catalysts,and thus is promising for practical applications.展开更多
Micropores are decisive to mechanical properties and thermal deformation capabilities of powder met-allurgy(P/M)Ti alloys sintered compacts.As a result,achieving express densification is of prime im-portance and has a...Micropores are decisive to mechanical properties and thermal deformation capabilities of powder met-allurgy(P/M)Ti alloys sintered compacts.As a result,achieving express densification is of prime im-portance and has attracted increasing attention recently.Induction heating owns the merits of high effi-ciency,short process,and low cost,and thus has huge potential to be used as a sintering approach for the fabrication of P/M Ti alloys.Nevertheless,the facilitated densification behavior associated with induction heating sintering remains unclear so far.To address it,powder metallurgy Ti6Al4V is manufactured via induction heating sintering with which the underlying sintering mechanism is investigated in-depth.It is found that induction heating could generate a fully densified compact in a remarkably shortened time,demonstrating its superior sintering efficiency as compared with conventional resistance furnace heat-ing.COMSOL finite element analysis reveals that the maximum current density during induction heating can reach 10^(6)A m^(–2)though the magnetic field strength is solely 0.02 T,leading to a slight tempera-ture difference of approximately 30℃between the interior and exterior of the billet.Furthermore,the rapid heating essentially starts at sharp corners of particles due to the potent current concentration ef-fect,which facilitates the cracking of the particle surface oxide film and thus enhances the direct contact between them.Moreover,the electromigration effect caused by induction current promotes the diffusion capability of elements,giving rise to expedited densification,alloying,and chemical homogenization.This work provides not only critical insight into the sintering mechanism of induction heating sintering but also significant guidance for low-cost powder metallurgy materials preparation.展开更多
Electromagnetic induction heating technology,characterized by its non-contact thermal heat transfer,diminished thermal inertia,and facile temperature management,is applied in this study to enhance catalytic methanol s...Electromagnetic induction heating technology,characterized by its non-contact thermal heat transfer,diminished thermal inertia,and facile temperature management,is applied in this study to enhance catalytic methanol steam reforming(MSR)reaction process.A two-dimensional reactor model was developed integrating electromagnetic field coupling with MSR reactions,fluid dynamics and heat transfer.In the reactor,heat is induced instantaneously on the magnetic material through an electromagnetic induction process,which generated by renewable electricity.Results showed that the Internal-Double Row Cylinder(IN-DRC,cylinder means that the shape of induction heating element is cylindrical.)highest heating efficiency is 38.3%,which is limited by the kinetics of MSR reaction.Here,thermal efficiency reaches its maximum with the reaction channel outlet temperature reaching about 580 K.Internal-Double Row Cylinder(IN-DRC)and Internal-Double Row Ball(IN-DRB,ball means that the shape of induction heating element is spherical)methanol conversions are virtually identical,with a maximum value close to 100%.Furthermore,the findings that the adoption of internal induced heating,in contrast to external heating,across the four reactor designs can effectively mitigate temperature gradient within the reactors.This reduction in thermal disparity significantly amplifies methanol conversion within the reactor,thereby markedly enhancing its overall performance in hydrogen production.Therefore,non-contact internal induction heating method has the potential for substantially hydrogen production processes.展开更多
CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using ...CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using EMIH-configured characterization and density functional theory,it is shownthat the EMIH-induced negative electric field at the electromagnetic interface facilitates CO_(2) dissociation and atomic oxygen transfer,which is the source of the promoting effect of EMIH.By employing pure H2 in a one-step high-temperature reduction process,the interfacial effect between the NiMgAl compound and the Fe fiber could be improved,thereby increasing the influence of the EMIH-induced electric field.Consequently,the R-NiMgAl/Fe fiber catalyst with EMIH achieves about 90%conversions of CH_(4) and CO_(2) at 500℃,while traditional heating-driven DRM on R-NiMgAl requires 700℃ to accomplish the same result.展开更多
Electricity is an efficient form of energy,and the growing interest in electricity-assisted manufacturing is motivated by its inherent energy saving and reduced environmental impact.Beyond this,Electromagnetic Process...Electricity is an efficient form of energy,and the growing interest in electricity-assisted manufacturing is motivated by its inherent energy saving and reduced environmental impact.Beyond this,Electromagnetic Processing of Materials(EPM)allows the fabrication of materials with new compositions,metastable phases and nanograined microstructures that cannot be obtained using conventional heating processes using furnaces.This review covers EPM for the manufacture of ceramic and metal bulk components,with a specific focus on the effects of electric fields and electromagnetic radiations on processing in a wide spectrum of frequencies ranging from DC(f=0 Hz)to visible light(f=10^(14)–10^(15)Hz).The manuscript is divided into two parts.The first part provides a comprehensive overview of the interactions between matter and electric field/current,including heating phenomena(resistive Joule,induction,dielectric heating,electric arcs)and athermal effects(electromigration,electroplasticity,electrochemical reactions,ponderomotive force and others).The second part is focused on the technological application of the techniques,covering heat treatments,joining,sintering and forming.Seven distinct physical phenomena are involved in EPM:resistive Joule and induction heating,electrochemical reactions,electroplasticity,electric arcs and electromagnetic heating based on radio and microwave frequencies(mainly used for heating dielectric materials;i.e.,dielectric heating)or on the IR/visible light(IR heating and lasers).展开更多
A coupled mathematical model was developed to describe the flow field,temperature distribution of molten steel in the tundish with the channel type induction heating.The molten steel motion was dominated under the com...A coupled mathematical model was developed to describe the flow field,temperature distribution of molten steel in the tundish with the channel type induction heating.The molten steel motion was dominated under the combined effect of the thermal buoyancy and the electro-magnetic forces(EMFs)due to the channel type induction heating.The results indicate that the thermal loss of molten steel in the tundish can be compensated effectively by the channel type induction heating.In addition,the molten steel would flow upward under the thermal buoyancy which can reduce the erosion of refractory.Moreover,the upward flow would increase the residence time of the molten steel in the tundish which provide more opportunities for the inclusion to reach the top surface of the tundish.展开更多
In order to overcome the pollution of the tratitional nozzle sand into the molten steel in tundish,a new method is proposed in this paper.In this method,the nozzle sand is substituted with iron-carbon alloy particles ...In order to overcome the pollution of the tratitional nozzle sand into the molten steel in tundish,a new method is proposed in this paper.In this method,the nozzle sand is substituted with iron-carbon alloy particles which have the same or similar compositions as the liquid steel.During casting processes,iron-carbon alloy forms solidification shell and the sintered layer in the upper nozzle to block the molten steel.When the slide gate is opened,the eletromagnetic induction heating is used to melt them so as to achieve 100%smoothly steel teeming.The electromagnetic induction heating effects were analyzed theoretically in the new slide gate system.Then the new method has been experimentally tested by using self-designed experimental device.The results show that the electromagnetic induction heating can complete the steel teeming within the required time.Furthermore,this steel-teeming technology can further improve the cleanliness of liquid steel.展开更多
The purpose of this paper is to investigate the feasibility of high-frequency induction heat for the line heating process through a series of experimental studies and numerical calculations. The results show that the ...The purpose of this paper is to investigate the feasibility of high-frequency induction heat for the line heating process through a series of experimental studies and numerical calculations. The results show that the heating temperature of induction heating meets the demands of steel plate bending, and the deformation of a steel plate heated by induction heating can achieve the same effect as flame heating. Meanwhile, the finite element model of moving induction heating of the plate is developed, and the comparison of the residual strain fields and transverse shrinkage between these two kinds of heating shows that great similarity has been achieved.展开更多
The key to acquire good metallurgical effects with induction heating tundish is to understand the flow field,temperature field and the movement of inclusions in the tundish with different induction heating power curve...The key to acquire good metallurgical effects with induction heating tundish is to understand the flow field,temperature field and the movement of inclusions in the tundish with different induction heating power curves.Based on the production of a factory,this work established a multi-field coupling mathematical model to find out the link between the heating power curve and the metallurgical effects of the tundish.The results indicated that the heating efficiency of an induction heating tundish not only was affected by the heating power,but also related to the flow and temperature field in the tundish.When the induction heater was used intermittently and the induction heater was turned on,the molten steel was controlled by electromagnetic force,and the flow field basically remained stable.However,when the induction heater was turned off,the velocity of molten steel got small,and the thermal buoyancy could greatly change the flow,forming short-circuit flow;besides,large number of inclusions suddenly escaped from the outlet of the tundish.When the molten steel was heated continuously,the flow field,temperature field and inclusions behavior remained basically unchanged.Considering both energy saving and maintaining good metallurgical effects,continuous heating(the power increasing stepwise over time)should be selected.展开更多
This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of ...This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.展开更多
Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature dis...Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature distribution in the induction brazing model. The in?uences of induction brazing parameters on the residual stresses of polycrystalline CBN abrasive grits have been analyzed, including the embedding depth, grit side length, etc. Results obtained show that the tensile stress with a 40% embedding depth is 292 MPa, which is the minimum on the bonding interface compared with other embedding depths. Meanwhile, the maximum tensile stress is 575 MPa, with an increase of 59% compared with that of a grit side length of 50 mm. Finally, the simulation results of the brazing residual stress of polycrystalline CBN abrasive grits have been con?rmed valid based on the residual stress measurement of the brazed monocrystalline CBN grit.展开更多
An experimental and numerical study on the temperature field induced in the ultra-high frequency induction heating is carried out.With an aim of predicting the thermal history of the workpiece,the influence factors of...An experimental and numerical study on the temperature field induced in the ultra-high frequency induction heating is carried out.With an aim of predicting the thermal history of the workpiece,the influence factors of temperature field,such as the induction frequency,the dimension of coil and the gap between coil and workpiece,are investigated considering temperature-dependent material properties by using FLUX 2Dsoftware.The temperature field characteristic in ultra-high induction heating is obtained and discussed.The numerical values are compared with the experimental results.A good agreement between them is observed with 7.9% errors.展开更多
Undoped nickel-based catalysts supported on depleted uranium oxide allow one to carry out CO_(2)methanation process under extremely low reaction temperature under atmospheric pressure and powered by a contactless indu...Undoped nickel-based catalysts supported on depleted uranium oxide allow one to carry out CO_(2)methanation process under extremely low reaction temperature under atmospheric pressure and powered by a contactless induction heating.By adjusting the reaction conditions,the catalyst is able to perform CO_(2)methanation reaction under autothermal process operated inside a non-adiabatic reactor,without any external energy supply.Such autothermal process is possible thanks to the high apparent density of the UO_x which allows one to confine the reaction heat in a small catalyst volume in order to confine the exothermicity of the reaction inside the catalyst and to operate the reaction at equilibrium heat in-heat out.Such autothermal operation mode allows one to significantly reduce the complexity of the process compared to that operated using adiabatic reactor,where complete insulation is required to prevent heat disequilibrium,in order to reduce as much as possible,the heat exchange with the external medium.The catalyst displays an extremely high stability as a function of time on stream as no apparent deactivation.It is expected that such new catalyst with unprecedented catalytic performance could open new era in the field of heterogeneous catalysis where traditional supports show their limitations to operate catalytic processes under severe reaction conditions.展开更多
Under various electromagnetic induction heating powers,different Al3Ti/Al composites were fabricated by in-situ synthesis method from aluminum and titanium fibers.Microstructures and particles distribution of the comp...Under various electromagnetic induction heating powers,different Al3Ti/Al composites were fabricated by in-situ synthesis method from aluminum and titanium fibers.Microstructures and particles distribution of the composites were examined by XRD,SEM and EDS.The results show that no other intermetallic compounds beside Al3Ti can be in-situ synthesized.Around the titanium fibers,the reaction zones and diffusion zones can be obviously found.Due to the stirring of the electromagnetic function,the formation of the micro-cracks inside the reaction zone was conducive to the peeling off of the Al3Ti particles,and ensures the continuous reaction between liquid aluminum and titanium fibers,as well as the diffusion of Al3Ti particles.At the same time,there were secondary splits of Al3Ti particles located in diffusion zones.Two-body abrasion test shows that with the increase of induction heating power,the wear rates of the composites reduced and the number of grooves decreased.展开更多
This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive ...This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive and capacitive parasitic components in the converter. The switch devices operate in a zero-voltage soft-switching mode. Consequently, the high voltage and high current spikes caused by parasitic inductors or capacitors oscillation do not occur in this circuit, and the high power loss caused by high frequency switching can be greatly reduced. A large value inductor is adopted between the input capacitor and the switches, thus, this novel converter shares the benefits of both voltage-type and current-type circuits simultaneously, and there are no needs of dead time between two switches. The working principles in different modes are introduced. Results of simulation and experiments operated at around 1 MHz frequency verify the validity of parasitic components absorption and show that this convener is competent for super high frequency applications.展开更多
Continuous steel strip casting lines in rolling miles are under active development.Due to high thermal losses the thin strip is cooling down very fast and therefore a sufficient heating system is necessary before fina...Continuous steel strip casting lines in rolling miles are under active development.Due to high thermal losses the thin strip is cooling down very fast and therefore a sufficient heating system is necessary before final rolling.Only induction heaters can realize the necessary fast heating of the strip and a good energy efEciency of heating.Because of induction heating lines for rolling mills are of extremely high power,all even small improvements in their design and operating modes have significant technical and economical effects.However,the heating lines need an optimal design of the complex induction systems and only numerical simulation is a way to solve the problem.Both two- and threedimensional numerical simulation approaches developed and applied for investigation and design of longitudinal induction heaters are described in the paper.The numerical models have been successfully used for development of modified coils allowing high efficient heating of thinner strip using the same operating frequency.Additionally electrical impedance of the modified coils has been provided on the level necessary for using the existing power supplies and matching equipment.Beside high electrical efficiency,the modified coils improve the temperature distribution over the strip width by increased heating of the strip edges.The optimized and modifies induction coils have been successfully tested in industrial line.展开更多
The electromagnetic,flow,heat transfer and inclusions motion model of the channel-type induction heating(IH)tundish was established,and the effect of the channel diameter on the metallurgical behavior of the tundish w...The electromagnetic,flow,heat transfer and inclusions motion model of the channel-type induction heating(IH)tundish was established,and the effect of the channel diameter on the metallurgical behavior of the tundish was studied.The results show that the magnetic field in the channel of the IH tundish tends to concentrate on the surface layer and the side near the coil.As the channel diameter is increased from 100 to 180 mm,the maximum value of magnetic flux density in the channel decreases by 0.125 T,and the maximum value of electromagnetic force decreases by 11.83×10^(5) N m^(-3);however,the off-center distance of magnetic field increases by 9.4 mm,and the Joule heat in the channel decreases by 1004 kW,which leads to the reduction in temperature rising rate of the tundish from 1.41 to 0.59 K min^(-1).When the channel diameter is 100,140 and 180 mm,the maximum velocity at the channel exit before heating is 0.59,0.29 and 0.18 m s^(-1),and after heating for 1800 s,it is 1.52,1.12 and 0.92 m s^(-1),respectively.In addition,the total inclusions escape ratio after heating for 1800 s with a channel diameter of 140 mm can be reduced by 12.39% compared to that before heating,and the maximum difference of escape ratios for each strand is only 4.51% and 5.32% before heating and after heating for 1800 s,respectively.Compared with the channel diameters of 100 and 180 mm,the channel diameter of 140 mm is more favorable to improve the metallurgical effect of the IH tundish.展开更多
基金supported by the National High-Tech Research and Development Program of China (No.2007AA03Z119)the Innovation Programs of China Electronics Technology Group Corporation (No.81AA10042)
文摘To meet the demands of continuous stream-line for component production in the thixo-forming industry, billet heating should be of high quality and in a controllable way. A 4-step inductive heating strategy for aluminum alloy A356 was performed. Thixotropic testing and microstructure analysis showed that a homogenous temperature distribution was achieved after temperature-power-time optimization. Theoretical analysis was given concerning the thermal conductivity and heat capacity of A356 between conventional and semisolid casting microstructures. The experimental results show that the optimized 4-step strategy could be the best strategy for billet heating during the thixo-forming of aluminum alloy A356.
文摘We examine a convective dissipation-free heat transfer in melts under the action of a stationary component of electromagnetic body force induced by frequency-modulated travelling magnetic field.The influence of MHD parameters of turbulent flow on the transfer process is studied.
文摘In the anticorrosive coating line of a welded tube plant, the current status and existing problems of the medium-frequency induction heating equipment were discussed.Partial renovations of the power control cabinet have been conducted.Parameters such as the DC current, DC voltage, intermediate frequency power, heating temperature, and the positioning signal at the pipe end were collected.A data acquisition and processing system, which can process data according to user needs and provide convenient data processing functions, has been developed using LabVIEW software.This system has been successfully applied in the coating line for the automatic control of high-power induction heating equipment, production management, and digital steel tube and/or digital delivery.
基金financial support from the National Key Research and Development Program of China(No.2022YFC3205300)National Natural Science Foundation of China(Nos.52100178 and 52370072)。
文摘To efficiently remove perfluorooctanoic acid(PFOA),we developed a composite of magnetic Fe_(3)O_(4)nanocrystals and MIL-101(an iron-based metal organic framework).Because of its high surface area,porous structure,and complexation between PFOA as confirmed by experimental results and density functional theory simulation,the magnetic composite showed a Langmuir adsorption capacity of 415 mg/g in the presence of various groundwater components,and thus adsorbed PFOA at environment-relevant concentration within 20 min.The catalyst loaded with PFOA can then be magnetically separated from the synthetic groundwater.This adsorption step concentrated PFOA near MIL-101 and resulted in a fast decomposition rate in the decomposition step,where MIL-101 served as an efficient Fenton agent due to its abundant Fe^(3+)/Fe^(2+)sites.Meanwhile,the alternative magnetic field was introduced to change the production pathway of reactive oxygen species and superoxide radical anions were produced,which was critical for PFOA degradation.In addition,the inductive heating effect heat the magnetic particles to445 K through an in-situ approach,which thus further accelerated Fenton reactions rate.In addition,and achieved a complete degradation of PFOA within 30 min.This newly developed Fenton catalyst demonstrates advantages over conventionally heterogeneous and homogeneous catalysts,and thus is promising for practical applications.
基金supported by the National Key Research and Development Program of China(No.2020YFB2008300)the National Natural Science Foundation of China(Nos.51971097 and 52301147)+2 种基金the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(No.YESS20210054)the Hubei Province Natural Science Foundation(No.ZRMS2022000863)the Fundamental Research Funds for the Central Universities of Huazhong University of Science and Technology(No.2172021XXJS010)and the project supported by State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China.
文摘Micropores are decisive to mechanical properties and thermal deformation capabilities of powder met-allurgy(P/M)Ti alloys sintered compacts.As a result,achieving express densification is of prime im-portance and has attracted increasing attention recently.Induction heating owns the merits of high effi-ciency,short process,and low cost,and thus has huge potential to be used as a sintering approach for the fabrication of P/M Ti alloys.Nevertheless,the facilitated densification behavior associated with induction heating sintering remains unclear so far.To address it,powder metallurgy Ti6Al4V is manufactured via induction heating sintering with which the underlying sintering mechanism is investigated in-depth.It is found that induction heating could generate a fully densified compact in a remarkably shortened time,demonstrating its superior sintering efficiency as compared with conventional resistance furnace heat-ing.COMSOL finite element analysis reveals that the maximum current density during induction heating can reach 10^(6)A m^(–2)though the magnetic field strength is solely 0.02 T,leading to a slight tempera-ture difference of approximately 30℃between the interior and exterior of the billet.Furthermore,the rapid heating essentially starts at sharp corners of particles due to the potent current concentration ef-fect,which facilitates the cracking of the particle surface oxide film and thus enhances the direct contact between them.Moreover,the electromigration effect caused by induction current promotes the diffusion capability of elements,giving rise to expedited densification,alloying,and chemical homogenization.This work provides not only critical insight into the sintering mechanism of induction heating sintering but also significant guidance for low-cost powder metallurgy materials preparation.
基金supported by Chongqing technology innovation and application demonstration project(CSTB2022TIAD-DEX0015)National Natural Science Foundation of China(50906104)Performance Incentive Guidance Project of Chongqing Scientific Research Institutions(cstc2022jxjl20016).
文摘Electromagnetic induction heating technology,characterized by its non-contact thermal heat transfer,diminished thermal inertia,and facile temperature management,is applied in this study to enhance catalytic methanol steam reforming(MSR)reaction process.A two-dimensional reactor model was developed integrating electromagnetic field coupling with MSR reactions,fluid dynamics and heat transfer.In the reactor,heat is induced instantaneously on the magnetic material through an electromagnetic induction process,which generated by renewable electricity.Results showed that the Internal-Double Row Cylinder(IN-DRC,cylinder means that the shape of induction heating element is cylindrical.)highest heating efficiency is 38.3%,which is limited by the kinetics of MSR reaction.Here,thermal efficiency reaches its maximum with the reaction channel outlet temperature reaching about 580 K.Internal-Double Row Cylinder(IN-DRC)and Internal-Double Row Ball(IN-DRB,ball means that the shape of induction heating element is spherical)methanol conversions are virtually identical,with a maximum value close to 100%.Furthermore,the findings that the adoption of internal induced heating,in contrast to external heating,across the four reactor designs can effectively mitigate temperature gradient within the reactors.This reduction in thermal disparity significantly amplifies methanol conversion within the reactor,thereby markedly enhancing its overall performance in hydrogen production.Therefore,non-contact internal induction heating method has the potential for substantially hydrogen production processes.
基金supported by the National Nature Science Foundation of China(Nos.22176187 and 22376193)the STS Program Supporting Project of Fujian Province&CAS(No.2023T3070)+1 种基金the Youth Innovation Promotion Association of CAS(No.2021304)the Guiding Project of Seizing the Commanding Heights of“Self-purifying City”(No.IUE-CERAE-202403).
文摘CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using EMIH-configured characterization and density functional theory,it is shownthat the EMIH-induced negative electric field at the electromagnetic interface facilitates CO_(2) dissociation and atomic oxygen transfer,which is the source of the promoting effect of EMIH.By employing pure H2 in a one-step high-temperature reduction process,the interfacial effect between the NiMgAl compound and the Fe fiber could be improved,thereby increasing the influence of the EMIH-induced electric field.Consequently,the R-NiMgAl/Fe fiber catalyst with EMIH achieves about 90%conversions of CH_(4) and CO_(2) at 500℃,while traditional heating-driven DRM on R-NiMgAl requires 700℃ to accomplish the same result.
基金the Thousand Talents Program of China and Sichuan Province。
文摘Electricity is an efficient form of energy,and the growing interest in electricity-assisted manufacturing is motivated by its inherent energy saving and reduced environmental impact.Beyond this,Electromagnetic Processing of Materials(EPM)allows the fabrication of materials with new compositions,metastable phases and nanograined microstructures that cannot be obtained using conventional heating processes using furnaces.This review covers EPM for the manufacture of ceramic and metal bulk components,with a specific focus on the effects of electric fields and electromagnetic radiations on processing in a wide spectrum of frequencies ranging from DC(f=0 Hz)to visible light(f=10^(14)–10^(15)Hz).The manuscript is divided into two parts.The first part provides a comprehensive overview of the interactions between matter and electric field/current,including heating phenomena(resistive Joule,induction,dielectric heating,electric arcs)and athermal effects(electromigration,electroplasticity,electrochemical reactions,ponderomotive force and others).The second part is focused on the technological application of the techniques,covering heat treatments,joining,sintering and forming.Seven distinct physical phenomena are involved in EPM:resistive Joule and induction heating,electrochemical reactions,electroplasticity,electric arcs and electromagnetic heating based on radio and microwave frequencies(mainly used for heating dielectric materials;i.e.,dielectric heating)or on the IR/visible light(IR heating and lasers).
基金Item Sponsored by National Natural Science Foundation of China[No.50934008]National Natural Science Foundation of China[NO.50904014]
文摘A coupled mathematical model was developed to describe the flow field,temperature distribution of molten steel in the tundish with the channel type induction heating.The molten steel motion was dominated under the combined effect of the thermal buoyancy and the electro-magnetic forces(EMFs)due to the channel type induction heating.The results indicate that the thermal loss of molten steel in the tundish can be compensated effectively by the channel type induction heating.In addition,the molten steel would flow upward under the thermal buoyancy which can reduce the erosion of refractory.Moreover,the upward flow would increase the residence time of the molten steel in the tundish which provide more opportunities for the inclusion to reach the top surface of the tundish.
基金Item Sponsored by the Science and Technology Program of Liaoning Province(Grant No.2011221009)the 111 project(Grant No.B07015)
文摘In order to overcome the pollution of the tratitional nozzle sand into the molten steel in tundish,a new method is proposed in this paper.In this method,the nozzle sand is substituted with iron-carbon alloy particles which have the same or similar compositions as the liquid steel.During casting processes,iron-carbon alloy forms solidification shell and the sintered layer in the upper nozzle to block the molten steel.When the slide gate is opened,the eletromagnetic induction heating is used to melt them so as to achieve 100%smoothly steel teeming.The electromagnetic induction heating effects were analyzed theoretically in the new slide gate system.Then the new method has been experimentally tested by using self-designed experimental device.The results show that the electromagnetic induction heating can complete the steel teeming within the required time.Furthermore,this steel-teeming technology can further improve the cleanliness of liquid steel.
基金Supported by the National Natural Science Foundation of China (50805016)
文摘The purpose of this paper is to investigate the feasibility of high-frequency induction heat for the line heating process through a series of experimental studies and numerical calculations. The results show that the heating temperature of induction heating meets the demands of steel plate bending, and the deformation of a steel plate heated by induction heating can achieve the same effect as flame heating. Meanwhile, the finite element model of moving induction heating of the plate is developed, and the comparison of the residual strain fields and transverse shrinkage between these two kinds of heating shows that great similarity has been achieved.
基金supported by National Natural Science Foundation of China(51474065 and 51574083)the 111 Project(2.0)of China(No.BP0719037).
文摘The key to acquire good metallurgical effects with induction heating tundish is to understand the flow field,temperature field and the movement of inclusions in the tundish with different induction heating power curves.Based on the production of a factory,this work established a multi-field coupling mathematical model to find out the link between the heating power curve and the metallurgical effects of the tundish.The results indicated that the heating efficiency of an induction heating tundish not only was affected by the heating power,but also related to the flow and temperature field in the tundish.When the induction heater was used intermittently and the induction heater was turned on,the molten steel was controlled by electromagnetic force,and the flow field basically remained stable.However,when the induction heater was turned off,the velocity of molten steel got small,and the thermal buoyancy could greatly change the flow,forming short-circuit flow;besides,large number of inclusions suddenly escaped from the outlet of the tundish.When the molten steel was heated continuously,the flow field,temperature field and inclusions behavior remained basically unchanged.Considering both energy saving and maintaining good metallurgical effects,continuous heating(the power increasing stepwise over time)should be selected.
文摘This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.
基金supported by the National Natural Science Foundation of China(No.51775275)the Fundamental Research Funds for the Central Universities(No.NE2014103 and No.NZ2016107)
文摘Residual stresses produced in polycrystalline CBN abrasive grits during a high-frequency induction brazing process are calculated by using ?nite element analysis, with a consideration of the nonuniform temperature distribution in the induction brazing model. The in?uences of induction brazing parameters on the residual stresses of polycrystalline CBN abrasive grits have been analyzed, including the embedding depth, grit side length, etc. Results obtained show that the tensile stress with a 40% embedding depth is 292 MPa, which is the minimum on the bonding interface compared with other embedding depths. Meanwhile, the maximum tensile stress is 575 MPa, with an increase of 59% compared with that of a grit side length of 50 mm. Finally, the simulation results of the brazing residual stress of polycrystalline CBN abrasive grits have been con?rmed valid based on the residual stress measurement of the brazed monocrystalline CBN grit.
基金Supported by the National Science and Technology Major Project of China(2012ZX04003081)
文摘An experimental and numerical study on the temperature field induced in the ultra-high frequency induction heating is carried out.With an aim of predicting the thermal history of the workpiece,the influence factors of temperature field,such as the induction frequency,the dimension of coil and the gap between coil and workpiece,are investigated considering temperature-dependent material properties by using FLUX 2Dsoftware.The temperature field characteristic in ultra-high induction heating is obtained and discussed.The numerical values are compared with the experimental results.A good agreement between them is observed with 7.9% errors.
基金ORANO Chimie-Enrichissement Co.for the financial support of this project。
文摘Undoped nickel-based catalysts supported on depleted uranium oxide allow one to carry out CO_(2)methanation process under extremely low reaction temperature under atmospheric pressure and powered by a contactless induction heating.By adjusting the reaction conditions,the catalyst is able to perform CO_(2)methanation reaction under autothermal process operated inside a non-adiabatic reactor,without any external energy supply.Such autothermal process is possible thanks to the high apparent density of the UO_x which allows one to confine the reaction heat in a small catalyst volume in order to confine the exothermicity of the reaction inside the catalyst and to operate the reaction at equilibrium heat in-heat out.Such autothermal operation mode allows one to significantly reduce the complexity of the process compared to that operated using adiabatic reactor,where complete insulation is required to prevent heat disequilibrium,in order to reduce as much as possible,the heat exchange with the external medium.The catalyst displays an extremely high stability as a function of time on stream as no apparent deactivation.It is expected that such new catalyst with unprecedented catalytic performance could open new era in the field of heterogeneous catalysis where traditional supports show their limitations to operate catalytic processes under severe reaction conditions.
基金Project(2015DFR50990-01)supported by International Cooperation Project of Ministry of Science and Technology of ChinaProjects(18JS060,18JS075)supported by the Shaanxi Key Laboratory of Nano-materials and Technology,China。
文摘Under various electromagnetic induction heating powers,different Al3Ti/Al composites were fabricated by in-situ synthesis method from aluminum and titanium fibers.Microstructures and particles distribution of the composites were examined by XRD,SEM and EDS.The results show that no other intermetallic compounds beside Al3Ti can be in-situ synthesized.Around the titanium fibers,the reaction zones and diffusion zones can be obviously found.Due to the stirring of the electromagnetic function,the formation of the micro-cracks inside the reaction zone was conducive to the peeling off of the Al3Ti particles,and ensures the continuous reaction between liquid aluminum and titanium fibers,as well as the diffusion of Al3Ti particles.At the same time,there were secondary splits of Al3Ti particles located in diffusion zones.Two-body abrasion test shows that with the increase of induction heating power,the wear rates of the composites reduced and the number of grooves decreased.
文摘This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive and capacitive parasitic components in the converter. The switch devices operate in a zero-voltage soft-switching mode. Consequently, the high voltage and high current spikes caused by parasitic inductors or capacitors oscillation do not occur in this circuit, and the high power loss caused by high frequency switching can be greatly reduced. A large value inductor is adopted between the input capacitor and the switches, thus, this novel converter shares the benefits of both voltage-type and current-type circuits simultaneously, and there are no needs of dead time between two switches. The working principles in different modes are introduced. Results of simulation and experiments operated at around 1 MHz frequency verify the validity of parasitic components absorption and show that this convener is competent for super high frequency applications.
文摘Continuous steel strip casting lines in rolling miles are under active development.Due to high thermal losses the thin strip is cooling down very fast and therefore a sufficient heating system is necessary before final rolling.Only induction heaters can realize the necessary fast heating of the strip and a good energy efEciency of heating.Because of induction heating lines for rolling mills are of extremely high power,all even small improvements in their design and operating modes have significant technical and economical effects.However,the heating lines need an optimal design of the complex induction systems and only numerical simulation is a way to solve the problem.Both two- and threedimensional numerical simulation approaches developed and applied for investigation and design of longitudinal induction heaters are described in the paper.The numerical models have been successfully used for development of modified coils allowing high efficient heating of thinner strip using the same operating frequency.Additionally electrical impedance of the modified coils has been provided on the level necessary for using the existing power supplies and matching equipment.Beside high electrical efficiency,the modified coils improve the temperature distribution over the strip width by increased heating of the strip edges.The optimized and modifies induction coils have been successfully tested in industrial line.
基金funded by the National Natural Science Foundation of China(NSFC)(Grant Nos.51874033 and U1860111).
文摘The electromagnetic,flow,heat transfer and inclusions motion model of the channel-type induction heating(IH)tundish was established,and the effect of the channel diameter on the metallurgical behavior of the tundish was studied.The results show that the magnetic field in the channel of the IH tundish tends to concentrate on the surface layer and the side near the coil.As the channel diameter is increased from 100 to 180 mm,the maximum value of magnetic flux density in the channel decreases by 0.125 T,and the maximum value of electromagnetic force decreases by 11.83×10^(5) N m^(-3);however,the off-center distance of magnetic field increases by 9.4 mm,and the Joule heat in the channel decreases by 1004 kW,which leads to the reduction in temperature rising rate of the tundish from 1.41 to 0.59 K min^(-1).When the channel diameter is 100,140 and 180 mm,the maximum velocity at the channel exit before heating is 0.59,0.29 and 0.18 m s^(-1),and after heating for 1800 s,it is 1.52,1.12 and 0.92 m s^(-1),respectively.In addition,the total inclusions escape ratio after heating for 1800 s with a channel diameter of 140 mm can be reduced by 12.39% compared to that before heating,and the maximum difference of escape ratios for each strand is only 4.51% and 5.32% before heating and after heating for 1800 s,respectively.Compared with the channel diameters of 100 and 180 mm,the channel diameter of 140 mm is more favorable to improve the metallurgical effect of the IH tundish.
