Uphill Teeming Utilizing TurboSwirl to Control Flow Pattern in Mold

Abstract

The flow pattern has widely been recognized to have an impact on the exogenous non‐metallic inclusion generation in the gating system and mold flux entrapment in the mold in the uphill teeming process. The possible solutions of the flow pattern control are required to be reliable and practical in order to improve the yield and the ingot quality in the steel production. In this work, a mathematical model of a new novel swirling flow generation component, TurboSwirl, was studied to investigate the flow pattern of steel in the gating system and molds based on the authors' previous study. The same calculation method and boundary conditions were adopted. The results show that a much calmer initial filling condition with less fluctuations is achieved in the mold with a swirling flow by using the TurboSwirl compared to previous studies. In addition, the initial position of the mold powder bags can further be lowered in the mold due to a decreased hump height. Moreover, the difference between the hump height and the surface height in the present model has a maximum value of 83 mm, which gives a lower risk of mold flux entrapment. Furthermore, the maximum wall shear stress value can generally be lowered with less fluctuations after the first hump formation in the mold at 2.5 s from the teeming start. In conclusion, the initial filling conditions can be substantially improved by the use of TurboSwirl flow pattern control.

Effect of TurboSwirl Structure on an Uphill Teeming Ingot Casting Process

“…[19] In the present work, some structural modifications were made based on the divergent nozzle with flaring angle to optimize the flow pattern in order to obtain a more even swirling flow generated by the TurboSwirl device. The first attempt made was to change the flaring angle of the divergent nozzle to minimize the axial velocity and the maximum wall shear stress, and the swirl number was calculated to make sure that the rotation of the liquid steel was strong enough to generate a swirling flow.…”

“…Moreover, a new swirling flow generator of a much larger scale for steel ingot casting was introduced, called TurboSwirl. [19] It uses the tangential velocity to generate the swirling flow at the intersection of the runners of ingot casting. Studies have been carried out which demonstrate that the filling conditions were much calmer during the initial filling stage, and that this resulted in a lower hump height and a lower maximum wall shear stress.…”

An Experimental and Numerical Study of Swirling Flow Generated by TurboSwirl in an Uphill Teeming Ingot Casting Process

“…Studies have been done to demonstrate that a much calmer filling condition can be observed during the initial filling stage, which results in a lower hump height and a lower maximum wall shear stress. 15) Moreover, Bai et al 16) showed that it was possible to lower the axial velocity and wall shear stress by changing the flaring angle of the divergent nozzle. Moreover, quite different flow patterns could be obtained when the vertical runner and the divergent nozzle were not placed at the center of the TurboSwirl.…”

“…In total, five TurboSwirl devices were manufactured. The dimension of the TurboSwirl used in this experiment was taken from Tan,15) but the diameter of the runners was modified from 45 mm to 50 mm due to a restriction in the manufacturing of the plexiglass tubes. The general dimension of the plexiglass TurboSwirl for this experiment is shown in Fig.…”

“…24) Furthermore, it has already been used to analyse the swirling flow generated by the swirl blade. [6][7][8][9][10]15) However, some published work simulating the turbulent swirling flow for a gas cyclone 25) and tundish 13,14) found that the Reynolds stress model (RSM) 26) can simulate the swirling flow most accurately compared to the experimental results. The numerical simulation part of this work used all three turbulence models above to test which one that best could describe the swirling flow more precisely, especially for the air-core vortex.…”