Analysis of influence of blocking flow operation at end of casting on characteristics of liquid steel in tundish
Taking the eight-strand tundish as the research object,through the combination and verification of numeri-cal simulation and physical simulation,explores the influence of blocking flow operation on the temperature field,flow field,liquid level fluctuation,dead zone distribution and inclusion removal rate at the end of casting.And the optimal blocking flow scheme was comprehensively determined to provide theoretical guidance for on-site produc-tion.The results show that the dead zone volume fraction can reach 2.0-2.5 times of the original,and the liquid sur-face wave height is enhanced.When Outlet1 is blocked,the fluctuation of position4 is the strongest.The dead zone volume percent of numerical,physical simulation and dead zone visualization results are 24.9%,31.7%and 26.2%,respectively.When Outlet3 and Outlet4 are blocked,the fluctuation of position 5 is the strongest.The dead zone volume percent is about 23.5%,29.6%and 24.3%in numerical,physical simulation and dead zone visu-alization results,respectively.Compared with the distribution of dead zone and the removal rate of inclusions during normal casting,when Outlet1 was blocked,the dead zone in the remote strand region expanded and the inclusion removal rate increased by 4.87%on average;when Outlet3 was blocked,the dead zone in the middle region expanded and the inclusion removal rate increased by 5.29%on average;when Outlet4 was blocked,the dead zone in the near strand region expanded and the inclusion removal rate increased by 7.61%on average.In addition,when outlet1 is blocked,the maximum outlet response time difference and the maximum average residence time difference under numerical and physical simulation are 14 s and 9 s respectively,and the maximum average residence time dif-ference are 27 s and 18 s respectively.The residence time distribution curve(RTD)has a high coincidence,and the temperature field is more uniform.Therefore,based on the multi-angle characterization results,if the blocking flow operation is necessary in the actual production process,in order to maintain the original flow characteristics of the liq-uid steel in the tundish and reduce the disorder and blindness of the blocking flow operation,blocking outlet1 strand is the best scheme.In addition,the fluid dead zone critical rate of 0.008 8 m/s can be used for fluid dead zone rate calibration,and its accuracy is mutually verified by numerical and physical simulations.
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