Experimental And Simulation Study On Liquid Metal Surface Behavior Under Electromagnetic Controlling

In the continuous casting process,the stability of molten steel surface in the mold is an important factor to determine the quality of casting.In the process of electromagnetic continuous casting,electromagnetic forces generated by alternating magnetic fields can cause fluctuations in the liquid surface.How to control the fluctuation and deformation of liquid surface is the key to improve the quality of casting.In order to efficiently and reasonably control the liquid metal surface deformation and fluctuations,the deformation and fluctuation behavior of liquid metal surface under electromagnetic control are studied by means of experimental and numerical simulation.Different forms of magnetic field generators were designed.A low melting point Ga-In-Sn alloy was used to simulate the molten steel.The alternating magnetic field generated by the magnetic field generator is measured by the electromagnetic induction method.And the magnetic field distribution under different parameters was investigated.The deformation and fluctuation of the liquid metal level under different parameters were measured by laser displacement sensor.The deformation law of the liquid steel in the three-dimensional model is analyzed by using the algorithm of two-way coupling between flow field and magnetic field.Experimental results show that the flow of liquid metal can impact on the surface,and form a drum package deformation on the free surface.With electromagnetic control,the height of drum package significantly reduced,and the fluctuations also weakened.With the current of coil of magnetic field generator increasing,the effect of electromagnetic control is more obvious.As a result,the surface deformation is reduced,and the fluctuations of liquid surface are further weakened.The distance between the magnetic field generator and the liquid surface has a certain effect on the effect of electromagnetic control.The closer the distance,the smaller the surface deformation and the weaker the fluctuations.The effect of the magnetic flux density on the liquid surface is considered.When the current of the magnetic field generator is increased or the distance of the magnetic field generator from the liquid level is reduced,the magnetic flux density on the initial surface will increase,the deceleration of upward impact speed in the liquid steel center will accelerate,the angle between downward return flow of liquid steel and horizontal liquid level will reduce,the surface deformation also will be reduced,the angle is the smallest when the surface area is gentle,When the current intensity on the surface is too large,the angle between downward return flow of liquid steel and horizontal liquid level will increase,the surface will be pressed out of a pit and there is still a drum package in the pit.Electromagnetic force to suppress surface deformation will also affect the internal flow of liquid steel.There should be a suitable current intensity for the deformation of liquid surface under electromagnetic control.The smaller the coverage area of coil,the smaller the electromagnetic control range,the greater the magnetic flux density in the control range.Coverage area is too large or too small will make the surface more uneven,the deceleration of upward impact speed in the liquid steel center will slow,the angle between downward return flow of liquid steel and horizontal liquid level will increase,the appropriate coverage area of the coil can play the best control effect.Increase the impact strength of the stream,the upward impact speed in the liquid steel center decay to negative is more slowly,the angle between downward return flow of liquid steel and horizontal liquid level will increase,the surface deformation also will be increased.The impact strength is different,its deformation range will be a corresponding change.With the electrical parameters and physical parameters changing,as long as the magnetic flux density in the center of the liquid surface remains constant,the liquid level in the center to remains unchanged.Increase the magnetic flux density,the drop of the liquid level becomes larger,the decreasing distance has a parabolic relationship with the magnetic flux density.Therefore,it is the key to control the surface deformation behavior of liquid steel by selecting an appropriate coverage area of the coil and controlling magnetic flux density on the liquid surface in different ways.