In order to improve the mould filling ability, the method for production of thin-walled castings in the travelingmagnetic field was applied. The relationship between magnetic field density and input voltage as well as...In order to improve the mould filling ability, the method for production of thin-walled castings in the travelingmagnetic field was applied. The relationship between magnetic field density and input voltage as well as distancewas investigated, and the mould filling length of A357 melt has been studied. The electromagnetic forces appliedon the melt were also analyzed. The result shows that the mould-filling length of the melt increase rapidly with theincrease of magnetic flux density. The mould filling lengths in gypsum upper mould and magnetic material uppermould were compared from the standpoint of application. It demonstrated that the steel upper mould is superior togypsum mould.展开更多
Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its format...Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its formation mechanism were obtained and discussed for thin-walled casting. The influences of magnetic field density on the filling ability, filling velocity and mold filling time have been studied. The differences in filling capability between gravity casting and casting under the traveling magnetic field have been compared. The results indicate that the mold filling ability of the gallium melt increases greatly under the condition of traveling magnetic field; the filling time is shortened from 18 s under gravity field to 3 s under the traveling magnetic field and average flow rate of the melt increases from 1.6 to 8.68 cm3/s; the change law of the cross-section morphology of the gallium melt during the mold filling is that at first, the cross-section area does not change, then it decreases gradually. When the front of the melt reaches the end of the mold cavity, the front melt will backfill the mold; the wider the width of mold cavity, the better the mold filling ability. The mold filling ability of gallium melt in mold with upper magnetic conductor is better than that without upper magnetic conductor.展开更多
A new apparatus was designed to measure the electromagnetic force and a computational study of the traveling magnetic field(TMF)and its application to the Ga-In-Sn melt(with low melting point),then the forces on Al,Mg...A new apparatus was designed to measure the electromagnetic force and a computational study of the traveling magnetic field(TMF)and its application to the Ga-In-Sn melt(with low melting point),then the forces on Al,Mg,and Li melt,were simulated. The result show that the electromagnetic force on the melt increases linearly with the increasing length of the melt in the TMF.The TMF-induced Lorentz force increases with increasing frequency,and then decreases.The maximum value is obtained when the current frequency is 160 Hz,over that frequency the force decreases rapidly.When the iron-core is activated,the force increases when the melt closes to the iron-core.The Lorentz forces have inversely-proportional relationships with the electrical resistivity,the dfx/dρdecreases and the dfy/dρincreases with the increasing electrical resistivity(df/dρis the slope of the Lorentz force profile).展开更多
The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electr...The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electromagnetic pumps able to provide high flow rates.Since in such cases the magnetic Reynolds number are quite large,it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside the pumping channel.The case where the velocity field is uniform in the channel cross section is firstly considered. Then,the coupling between the electromagnetic aspects with the hydrodynamic ones in a 2D axisyrnmetric fmite element model is studied,in order to compare the magnetic convection and the magnetic diffusion.展开更多
基金The author gratefully appreciate key project (59995440) of the National Natural Science Foundation of China and 973 Project (G2000067202-2) for the financial support.
文摘In order to improve the mould filling ability, the method for production of thin-walled castings in the travelingmagnetic field was applied. The relationship between magnetic field density and input voltage as well as distancewas investigated, and the mould filling length of A357 melt has been studied. The electromagnetic forces appliedon the melt were also analyzed. The result shows that the mould-filling length of the melt increase rapidly with theincrease of magnetic flux density. The mould filling lengths in gypsum upper mould and magnetic material uppermould were compared from the standpoint of application. It demonstrated that the steel upper mould is superior togypsum mould.
文摘Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its formation mechanism were obtained and discussed for thin-walled casting. The influences of magnetic field density on the filling ability, filling velocity and mold filling time have been studied. The differences in filling capability between gravity casting and casting under the traveling magnetic field have been compared. The results indicate that the mold filling ability of the gallium melt increases greatly under the condition of traveling magnetic field; the filling time is shortened from 18 s under gravity field to 3 s under the traveling magnetic field and average flow rate of the melt increases from 1.6 to 8.68 cm3/s; the change law of the cross-section morphology of the gallium melt during the mold filling is that at first, the cross-section area does not change, then it decreases gradually. When the front of the melt reaches the end of the mold cavity, the front melt will backfill the mold; the wider the width of mold cavity, the better the mold filling ability. The mold filling ability of gallium melt in mold with upper magnetic conductor is better than that without upper magnetic conductor.
基金Project supported by the Program of Excellent Team in Harbin Institute of Technology,China
文摘A new apparatus was designed to measure the electromagnetic force and a computational study of the traveling magnetic field(TMF)and its application to the Ga-In-Sn melt(with low melting point),then the forces on Al,Mg,and Li melt,were simulated. The result show that the electromagnetic force on the melt increases linearly with the increasing length of the melt in the TMF.The TMF-induced Lorentz force increases with increasing frequency,and then decreases.The maximum value is obtained when the current frequency is 160 Hz,over that frequency the force decreases rapidly.When the iron-core is activated,the force increases when the melt closes to the iron-core.The Lorentz forces have inversely-proportional relationships with the electrical resistivity,the dfx/dρdecreases and the dfy/dρincreases with the increasing electrical resistivity(df/dρis the slope of the Lorentz force profile).
文摘The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electromagnetic pumps able to provide high flow rates.Since in such cases the magnetic Reynolds number are quite large,it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside the pumping channel.The case where the velocity field is uniform in the channel cross section is firstly considered. Then,the coupling between the electromagnetic aspects with the hydrodynamic ones in a 2D axisyrnmetric fmite element model is studied,in order to compare the magnetic convection and the magnetic diffusion.
