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The performance of gas blown in side walls of a single strand tundish is numerically simulated. Three cases are studied, i.e. tundish without gas blown, tundish with gas blown from the right side wall, and from the front wall. The vortex circulating flow is the main flow structure in tundish without gas blown. The gas blown from the right side wall of tundish will significantly change the flow field. The short-circuit flow that the tracer flow along the bottom of tundish to the outlet is becoming the main flow pattern. The RTD curve shows a rapid increase tendency. An anticlockwise flow near the top surface is formed. The mixing of tracer in the tundish is delayed and the dead volume fraction is increased when compared with the tundish without gas blown case. In contrast, the gas blown from the front wall of tundish will divide the tundish into two parts. The strong circulation flow in two parts is formed. Besides, the mixing of tracer is faster and the dead volume fraction is lower than that of the case without gas blown. This case may be an optimized gas blown technology in tundish.

The flow field, tracer dispersion and uniformity of strands in two designs of four-strand tun-dishes under normal conditions and single-strand blockage conditions are studied by numerical simulation. The casting speed (flow rate) of strands are increasing uniformly or non-uniformly to improve the strand blockage condition. The uniformity of strands of the cases are evaluated by a novel outflow percentage analysis method. The results show that the flow field in the tundish does not change significantly when the single-strand is blocked or the casting flow rate is increased. After blockage of one strand, the consistency of each strand of u-shaped weir tundish is better than that of double-weir tundish. With the uniform increasing of the casting flow rate, the response time of each strand decreases and the outflow percentage increases. However, the uniformity of strands improved slightly in double-weir tundish but decreased in u-shaped tundish. For the double-weir tundish, significantly increasing the casting flow rate of the strand located in the blocked part by a factor of 1.5 and slightly increasing the casting flow rate of the other strands by a factor of 1.25, the consistency of each strand is the best. For the u-shaped weir tundish, the consistency of each strand is improved by non-uniform increasing of the casting flow rate of the strands. The flow rate of the strand located in the blocked part and the other strands is increased by a factor of 1.25, and 1.375 or 1.2 and 1.4 are the optimized cases.

Three-dimensional computational fluid dynamics simulations were carried out to investigate the multiphase flow and heat transfer in a round mold, when using swirling flow generator (SFG) designs in a tundish. The results show that an impinging flow in the mold is significantly suppressed by using a SFG design, compared to when using a conventional tundish. This is due to the rotational flow momentum, which forces the steel to move toward the mold wall. When using SFG designs, the whole flow field shows periodic characteristics in transient simulations. At a given casting speed, the velocity fluctuation period and fluctuation range in the submerged entry nozzle depend on the SFG inlet area as well as the inlet velocity. As the inlet velocity increases from 0.185 to 0.37 m/s (inlet area decreases from 0.0048 to 0.0024 m2), the velocity fluctuation period decreases from 3 to 2 seconds and the fluctuation range increases from ± 10.5 to ± 18.2 pct. However, a symmetrical distribution of the flow field is obtained in the time-averaged results of 9 and 6 seconds intervals for SFG inlet velocities of 0.185 and 0.37 m/s, respectively. In addition, within one velocity fluctuation period, the time-averaged temperature field generally has a uniform distribution. As the SFG inlet velocity increases from 0.185 to 0.37 m/s, the steel super-heat further decreases in the mold and the temperature is increased by around 2 K near the meniscus. Finally, in the current mold with a diameter of only 150 mm, the removal ratio of inclusions to the mold top surface is low by using both SFG designs. The removal ratio of 10 μm spherical inclusions is 10 pct lower compared to when using a conventional tundish.

A transient multiphase flow model is established by solving the heterogeneous dynamic equation to simulate the process of the slag entrapment in the tundish, which can provide data for the trial production to reduce the tundish residue on the premise of ensuring no slag entrapment. A numerical simulation of critical slag entrapment height of 60 t tundish under different steel throughputs is analyzed, and the following conclusions are obtained: when the steel throughput is 3.5 t/min, 4.5 t/min, 5.5 t/min, and 6.4 t/min, the critical time of the risk of slag entrapment are 1042 s, 691 s, 561 s, and 476 s after casting end, respectively. The heights of slag entrapment are 186.9 mm, 202.9 mm, 220.5 mm, and 222.5 mm, and the heights without slag entrapment are 202.4 mm, 214.6 mm, 236.1 mm, and 238.0 mm with the throughput of 3.5 t/min, 4.5 t/min, 5.5 t/min, and 6.4 t/min.

The continuous casting tundish is a very important metallurgical reactor in continuous casting production. The flow characteristics of tundishes are usually evaluated by residence time distribution (RTD) curves. At present, the analysis model of RTD curves still has limitations. In this study, we reviewed RTD curve analysis models of the single flow and multi-flow tundish. We compared the mixing model and modified combination model for RTD curves of single flow tundish. At the same time, multi-strand tundish flow characteristics analysis models for RTD curves were analyzed. Based on the RTD curves obtained from a tundish water experiment, the applicability of various models is discussed, providing a reference for the selection of RTD analysis models. Finally, we proposed a flow characteristics analysis of multi-strand tundish based on a cumulative time distribution curve (F-curve). The F-curve and intensity curve can be used to analyze and compare the flow characteristics of multi-strand tundishes. The modified dead zone calculation method is also more reasonable. This method provides a new perspective for the study of multi-strand tundishes or other reactor flow characteristics analysis models.

With the increasing demand for special steel, the quality of steel has become critical during the continuous casting tundish process. In recent years, tundish heating technology has played a key role in low superheat casting. Toward this, researchers have reported on the metallurgical effects of induction heating tundish (IHT). From 1984 to date, the channel-type IHT has been investigated in the production of continuous casting of special steel. In this article, the principle of this channel-type IHT technology and equipment composition were illustrated. A brief summary and comments were undertaken on the channel-type IHT, including physical modeling and numerical modeling. The application development trend of tundish induction heating equipment is summarized combined with industrial application data, which provide a reference for a better understanding of the induction heating process of tundish.

This paper presents the results of studies on the occurrence of transient disturbances in the hydrodynamic system of a tundish feeding area and their effect on the casting process. In addition, the effect of changes in the level of superheating of the molten steel fed to the tundish on the evolution of the hydrodynamic system was analyzed. The studies were conducted with the use of a physical model of the tundish and a numerical model, representing the industrial conditions of the process of the continuous casting of steel. When a tundish is fed through a modified ladle shroud that slows down the momentum of the stream, this creates favorable conditions for the emergence of asymmetrical flow within the working tundish volume. The higher the degree of molten steel reheating in the ladle furnace, the stronger the evolution of the hydrodynamic structures in the tundish during the casting process.

In this paper, the influence of the novel design of a ladle shroud (LS) on the liquid steel flow structure inside the working volume of a two-strand slab tundish was assessed, determining the best solutions for LS use to achieve the optimal level of active flow zones and protect the tundish lining. A 0.33 scale water model was used for physical experiments. Numerical simulations were carried out in the Ansys-Fluent 12.1 software for a 1:1 scale tundish. The effect of the influence of LS type, LS immersion depth, LS side ports position, LS misalignment and casting speed was examined. Finally, the use of the “umbrella” ladle shroud allows stable hydrodynamics to be maintained even with shroud misalignment. Moreover, the “umbrella” ladle shroud effectively decreases the average velocity of liquid steel inside the tundish and significantly decreases shear stresses and dynamic pressure at the tundish lining in the tundish pouring area.

A three-dimensional mathematical model has been established for a novel metallurgy process coupling an annular gas curtain with swirling flow at tundish upper nozzle. The discrete phase model and volume of fluid model were applied to simulate the gas–liquid multiphase flow behavior in tundish and nozzle. The effect of argon flow rate on the migration behavior of bubbles and interface behavior between steel and slag was also investigated. The presented results indicate that the novel coupling process can significantly change the flow pattern in the stream zone of a tundish, prolong the average residence time of liquid steel, and reduce the dead fraction. A complete annular gas curtain is formed around the stopper rod of tundish. Under the action of drag force of liquid steel, a part of small bubbles enter the nozzle through the swirling grooves and gather toward the center of the nozzle by centripetal force. As the argon flow rate increases, the volume fraction of argon gas entering the nozzle increases, which enhances the swirl intensity and increases the concentration of bubbles in the nozzle. To avoid the formation of slag open eye in tundish, the argon flow rate should not exceed 8 L min −1 .

This study aims to use Computational Fluid Dynamics (CFD) analysis to improve inclusion removal efficiency in tundishes used in the steelmaking industry, with the broader goal of promoting more sustainable steel production and supporting circular economy objectives by producing cleaner steel. Inclusions are non-metallic particles, such as alumina, that enter the tundish with the molten steel and travel through it; if not removed, they can exit through the nozzles and adversely affect the mechanical properties of the final product and process yield. An existing tundish design is modified using three passive techniques, including adding a vertical dam, adding a horizontal baffle, and inclining the side walls, to assess their influence on fluid flow behavior and inclusion removal. Residence time distribution (RTD) analysis is employed to evaluate flow characteristics via key metrics such as dead zone and plug flow volume fractions, as well as plug-to-dead and plug-to-mixed flow ratios. In parallel, a discrete phase model (DPM) analysis is conducted to track inclusion trajectories for particles ranging from 5 to 80 μm. Results show that temperature gradients due to heat losses significantly influence flow patterns via buoyancy-driven circulation, changing RTD characteristics. Among the tested modifications, inclining the side walls proves most effective, achieving average inclusion removal improvements of 8% (Case B1) and 19% (Case B2), albeit with increased heat loss due to greater top surface exposure. Vertical dam and horizontal baffle, despite showing favorable RTD metrics, generally reduce the inclusion removal rate, highlighting a disconnect between RTD-based predictions and DPM-based outcomes. These findings demonstrate the limitations of relying solely on RTD metrics for evaluating tundish performance and suggest that DPM analysis is essential for a more accurate assessment of inclusion removal capability.