Study On The Flow Control In Thin Slab Continuous Casting Mold

In this paper,the combination of physical simulation and numerical simulation is used to study the new immersion nozzle of thin slab continuous casting mold to optimize the flow field in the mold and the influence on the slag behavior.The control flow effect and application feasibility of the new dissipative immersion nozzle are studied and verified.Firstly,through investigate on the research progress of crystallizer immersion nozzles in recent years,the research direction of optimizing the immersion nozzle structure is clarified.Then,three mathematical models applied in calculating the slag slag behavior in the crystallizer were evaluated.The analysis verified the application effect of each mathematical model.The stand k-? model(SKE),the large eddy simulation model(LES),and the detached eddy simulation(DES)model were evaluated in this paper.The results show that the detached eddy simulation(DES)has obvious advantages over the stand k-? model model(SKE)and the large eddy simulation model(LES)in the simulation of turbulent flow in the immersion nozzle and the mold.Aiming at the problem of two-phase flow of steel slag in the physical simulation experiment crystallizer,the similarity criterion that the physical simulation needs to satisfy is derived according to the Buckingham ? theorem,and it is concluded that We,Re,Fr,?1/?2,?1/?2 should be satisfied that these are all similar.A comparative analysis of the experimental oils that can be accessed in daily life,and finding the best oil(silicone oil AK 0.65,density ratio?1.3)that can satisfy the water simulation experiment of the mold slag phenomenon to the greatest extent.Based on the interfacial tension between the oil and water,the similarity ratio of the water model(?=0.5)can be determined.The mechanism analysis of the main form of reflow slag in the mold is carried out.The water simulation and the numerical calculation experiment results of the prototype immersion nozzle and the dissipative immersion nozzle are compared,it is verified that the liquid level of the crystallizer is more stable after using the dissipative immersion nozzle,and the slag phenomenon is reduced.On the basis of the numerical calculation results,the concept of the slag rate ? is proposed.By comparing the slag rate to quantitatively analyze the movement of the slag that has been entrained to the lower part of the crystallizer,the slag drop in the crystallizer photographed by the high-speed camera is compared with the result of numerical calculation.The analysis shows that the area where the serious slag is likely to occur inside the crystallizer is 0.43m from the nozzle and 0.48m below the meniscus.The results obtained by PIV experiment are basically consistent with the results calculated by DES model,which verifies the scientific reliability of the research results.The use of a dissipative immersion nozzle can improve the flow field distribution inside the crystallizer,thereby achieving the purpose of adjusting the liquid level in the crystallizer.