Research On The Flow Field Of Ladle And Long Nozzle In The Process Of Slag Detection

The thesis is based on slag detection in ladle casting process,and analyzed the flow field inside the ladle and long nozzle.The object of slag detection is molten steel and steel slag.The movement behavior of molten steel and steel slag will directly affect the detection results.Therefore,it is necessary to study the flow field inside the ladle and long nozzle.At present,there are three methods to research the flow field,including the oretical analysis,experimental simulation and numerical simulation.Firstly,the thesis analyzed the theory of flow field,and got the motion state of molten steel and slag and argon in the ladle,sliding nozzle,and long nozzle.Opening of sliding gate,ladle slag thickness,initial liquid level height,argon flow,nozzle inner wall roughness and bottom nozzle position are the main factors influencing the flow field.Because in the actual production process,the roughness of the nozzle and the location of the nozzle always remain unchanged,and the flow field will not change.Therefore,the research will focus on the three factors,which are the initial liquid level height of the ladle,the thickness of the steel slag and the argon flow rate.Secondly,the thesis used the method of numerical simulation to analyze the flow field.The numerical simulation is operated under the Fluent software platform,and established a three-phase flow model of molten steel,slag and argon gas.The parameters of the flow field are quantized by Fluent and the motion behavior of molten steel,slag and argon gas can be described in detail by the k-? turbulent model.Through the method of numerical simulation,the relationship between the flow field and molten steel,slag and argon gas was also obtained in the end.Thirdly,the thesis also used the method of water-model experiment to analyze the flow field,and applied the initial liquid level height,thickness of slag,argon flow rate as the study variables,the thesis also designed the experiment,and came to a series of conclusions.The experiments'results shown that the thickness of slag is the main factor affecting the flow field of the ladle,and the flow rate of the argon gas is the main factor affecting the flow field of long nozzle.Finally,the thesis compared the results of numerical simulation with the results of the water-model experiment and found out the same points and different points of view.The following conclusions are obtained by using the theoretical knowledge.The thickness of slag and the flow rate of the argon gas are two main influencing factors of flow field,and the flow rate of the argon gas is a direct factor affecting the critical opening of the sliding nozzle.The thesis also used the curve fitting method to find out the relationship between the flow rate and the critical opening.In process of the ladle casting,the critical opening of sliding nozzle which make detection equipment does not produce error signals is 30%...