Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment an...Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment and production.In this study,a 3-D finite element (FE) method based on experimental verification was applied to calculate the magnetic flux density (Bz).The effects of the power parameters and the induction coil on the magnetic field distribution in the cold crucible were investigated.The results show that higher current intensity and lower frequency are beneficial to the increase of Bz at both the segment midpoint and the slit location.The induction coil with racetrack section can induce greater Bz,and a larger gap between the induction coil and the shield ring increases Bz.The mechanism for this effect is also discussed.展开更多
A novel electromagnetic induction detector with two inductors for CE was described here.The two inductors were used as signal detection and reference,respectively.The parameters affecting the detector performance（inc...A novel electromagnetic induction detector with two inductors for CE was described here.The two inductors were used as signal detection and reference,respectively.The parameters affecting the detector performance（including coil turns,detection distance, excitation frequency,voltage,etc.） were optimized.Under the optimum condition,the feasibility of the detector was examined by analyzing inorganic ions.The fabricated detector showed good linear relationship between the response and the analytes concentrations,with a detection limit of 13μmol/L for Na~＋（S/N = 3）.A variety of advantages,such as simple construction, ease of operation,and considerably universal response,suggested this novel detector a promising application prospect in analytical area.展开更多
This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of ...This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of 50~150 mm from the both edges,so Transverse Flux Induction Coil(TFIC)including a magnetic core is proposed and optimized to supplement this fault.The solutions on the electromagnetic field are obtained numerically by commercial code MAXWELL 3D software from ANSYS Corp.and then,verified experimentally by pilot-scale tests,in which the TFIH was manufactured with a nominal power of 100 kW at a fundamental frequency of 1 kHz.Ultimately,TFIC having geometrically the optimized magnetic core made the heating pattern U-shaped,so could supply a desirable temperature profile for the rolling process.展开更多
For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable mag...For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.展开更多
While a small-radius induction bend is manufactured,various cross-section distortions may occur,such as its cross section tending to be elliptic,and wall thickness reduction or increase.These defects may deteriorate t...While a small-radius induction bend is manufactured,various cross-section distortions may occur,such as its cross section tending to be elliptic,and wall thickness reduction or increase.These defects may deteriorate the bearing capacity of pipelines.In order to study the effect of cross-section distortion on the performance of small-radius induction bends,3D(D refers to pipe diameter)induction bends were manufactured based on different combinations of process parameters.Then,the cross-section distortion,structure properties and their correlation of 3D bends and conventional 5D bends were analyzed comprehensively by means of cross-section geometry analysis,distortion analysis,physical and chemical property test,micro-structural analysis and so on.The following results were obtained.First,the wall thickening/thinning rate of 3D bends is about 2 times that of 5D bends,and the roundness of 3D bends is about 2e4 times that of 5D bends.Second,the cross-section distortion of 3D bends is obvious,so its heating temperature varies greatly in different parts,leading to different structure morphologies and contents.As a result,the numerical distribution of mechanical properties of each part of 3D bends(e.g.intrados,extrados and neutral zone)is discrete.Third,the strength at the intrados of most bends doesn't meet the standard,and it is sorted form the higher to the lower as extrados,neutral zone and intrados while the sequence of Charpy impact toughness is right contrary to the strength.Fourth,the strength at intrados and extrados decreases with the increase of roundness.The strength at intrados decreases with the increase of thickening rates.And the strength at extrados increases with the increase of thinning rates.展开更多
基金financially supported by the National Basic Research Program of China (Grant No.2011CB605504)
文摘Bottomless electromagnetic cold crucible is a new apparatus for continuous melting and directional solidification;however,improving its power efficiency and optimizing the configuration are important for experiment and production.In this study,a 3-D finite element (FE) method based on experimental verification was applied to calculate the magnetic flux density (Bz).The effects of the power parameters and the induction coil on the magnetic field distribution in the cold crucible were investigated.The results show that higher current intensity and lower frequency are beneficial to the increase of Bz at both the segment midpoint and the slit location.The induction coil with racetrack section can induce greater Bz,and a larger gap between the induction coil and the shield ring increases Bz.The mechanism for this effect is also discussed.
基金support from the National Natural Science Foundation of China(Nos20727006 and 21075139)
文摘A novel electromagnetic induction detector with two inductors for CE was described here.The two inductors were used as signal detection and reference,respectively.The parameters affecting the detector performance（including coil turns,detection distance, excitation frequency,voltage,etc.） were optimized.Under the optimum condition,the feasibility of the detector was examined by analyzing inorganic ions.The fabricated detector showed good linear relationship between the response and the analytes concentrations,with a detection limit of 13μmol/L for Na~＋（S/N = 3）.A variety of advantages,such as simple construction, ease of operation,and considerably universal response,suggested this novel detector a promising application prospect in analytical area.
文摘This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of 50~150 mm from the both edges,so Transverse Flux Induction Coil(TFIC)including a magnetic core is proposed and optimized to supplement this fault.The solutions on the electromagnetic field are obtained numerically by commercial code MAXWELL 3D software from ANSYS Corp.and then,verified experimentally by pilot-scale tests,in which the TFIH was manufactured with a nominal power of 100 kW at a fundamental frequency of 1 kHz.Ultimately,TFIC having geometrically the optimized magnetic core made the heating pattern U-shaped,so could supply a desirable temperature profile for the rolling process.
基金National Key Lab for Electronic Measurement and Technology,North University of China(No.9140C120401080C12)
文摘For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.
基金supported by the National Major Research and Development Project“Research on Disaster-caused Mechanism and Evolution Rules of Damages of Oil&Gas Pipelines and Storage&Transportation Facilities”(No.:2016YFC0802101)Scientific New Star Project of Shaanxi Province“Quality Forecast and Defect Control of Mold-free Hot-bending Cross Section with Small Radius of Pipe Material with Large Caliber”(No.:2015KJXX-73).
文摘While a small-radius induction bend is manufactured,various cross-section distortions may occur,such as its cross section tending to be elliptic,and wall thickness reduction or increase.These defects may deteriorate the bearing capacity of pipelines.In order to study the effect of cross-section distortion on the performance of small-radius induction bends,3D(D refers to pipe diameter)induction bends were manufactured based on different combinations of process parameters.Then,the cross-section distortion,structure properties and their correlation of 3D bends and conventional 5D bends were analyzed comprehensively by means of cross-section geometry analysis,distortion analysis,physical and chemical property test,micro-structural analysis and so on.The following results were obtained.First,the wall thickening/thinning rate of 3D bends is about 2 times that of 5D bends,and the roundness of 3D bends is about 2e4 times that of 5D bends.Second,the cross-section distortion of 3D bends is obvious,so its heating temperature varies greatly in different parts,leading to different structure morphologies and contents.As a result,the numerical distribution of mechanical properties of each part of 3D bends(e.g.intrados,extrados and neutral zone)is discrete.Third,the strength at the intrados of most bends doesn't meet the standard,and it is sorted form the higher to the lower as extrados,neutral zone and intrados while the sequence of Charpy impact toughness is right contrary to the strength.Fourth,the strength at intrados and extrados decreases with the increase of roundness.The strength at intrados decreases with the increase of thickening rates.And the strength at extrados increases with the increase of thinning rates.
