Synthesis of a CFD Benchmark Exercise: Examining Fluid Flow and Residence-Time Distribution in a Water Model of Tundish

Sheng, Dong-Yuan

doi:10.3390/ma14185453

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…The stimulation–response method [ 13 , 23 ] was adopted in this experiment. When the liquid level of tundish reached a given height, 100 mL saturated KCl solution was injected as a pulse tracer from a side port mounted at the upper position of the ladle shroud.…”

Section: Methodsmentioning

confidence: 99%

Effect of Flow Field Optimization of an Asymmetric Multi-Strand Tundish on the Quality Consistency of Cracking Con-Rod Steel

et al. 2022

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Cracking con-rod is an advanced high-precision connecting structure based on brittle expansion, breaking and reconnection of steel, to solve the problem of assembly circle missing. High carbon micro-alloyed steel C70S6, as a dominant material for the production of cracking con-rod, has extremely strict requirements on non-metallic inclusions in steel and microstructure stability. Continuous casting tundish plays an important role in removing large-sized inclusions and stabilizing casting quality. Aiming at the inconsistent casting quality of C70S6 steel produced by a three-strand asymmetric tundish and the frequent occurrence of slag entrapment problems in Xining Special Steel, the tundish structure was optimized by means of physical modelling combined with numerical simulation, and the quality of the bloom castings and subsequent hot-rolled products before and after optimization were compared based on volume production. The results show that a new flow control design to the tundish can effectively improve the consistency of its metallurgical effect for each of the three strands and the following overall product quality, in which the flow field and temperature field in the tundish are more uniform. This is due to the adoption of a vortex inhibitor and an optimized wall structure according to the measured RTD curve, ink trajectory and numerical simulation on the 3-D streamline contours and temperature distribution in the tundish. The peak concentration of outlet 1 is decreased from 6.5 before optimization to less than 2.0 after optimization, which means the elimination or alleviation of the local short-circuit flow. The maximum temperature difference of C70S6 molten steel measured at the outlets of the tundish three strands is decreased from 2–5 °C to 1–3 °C, which is in good agreement with the numerical simulation results. The difference in columnar crystal ratio of the corresponding bloom castings is decreased from 2.27–3.17% to 1.26–1.85%, and the consistency of central carbon segregation index is also significantly improved. In addition, the difference in oxygen content among the three strand blooms is decreased from 1.7–3.5 ppm to 0.8–1.9 ppm. As a result, the overall mechanical properties and microstructure stability of the hot-rolled products are improved statistically, in which the hardness fluctuation is decreased from 84 HBW to 60 HBW, the inclusion grade of types B + C + D + Ds is reduced to 1.105, and the occurrence rate of Ds dropped to 0.118%. Accordingly, the failure rate of the cracking con-rod is controlled stably within 4‰, and the fracture is generally smoother than that before tundish optimization. In summary, the flow field optimization to a multi-strand asymmetric tundish has a clear effect on improving the overall quality of its bloom castings and rolled products, which should be paid more attention industrially. Meanwhile, the present study provides a reliable theoretical and experimental reference for the improvement of metallurgical effects of an asymmetric-typed tundish commonly used in special steel production.

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Section: Methodsmentioning

confidence: 99%

Effect of Flow Field Optimization of an Asymmetric Multi-Strand Tundish on the Quality Consistency of Cracking Con-Rod Steel

et al. 2022

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“…The proposed best practice guidelines in tundish simulation were applied in the present study. 29) The utilization of an adequately refined mesh was an important step in achieving accuracy in CFD simulations. To investigate the effect of mesh size on the mean age distribution, two mesh sizes with 0.002 m and 0.003 m were compared.…”

Section: Model Validation and Verificationmentioning

confidence: 99%

Application of Mean Age Theory in Multi-strand Tundish

Sheng

2023

ISIJ Int.

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The mean age theory has recently been used to analyze the mixing efficiency in a single-strand tundish. The spatial distribution of the mean age was obtained by using a steady-state calculation. By applying the new theory of mean age, the computing cost was two orders of magnitude lower than when using the conventional theory of residence time distribution (RTD). This study aimed at extending the application of the mean age theory to a multi-strand tundish. Theoretical relations between the mean age and RTD were analyzed and compared for the tundish applications. A new criterion, the standard deviation of flowweighted mean age at the multiple outlets, was applied focusing on the consistency of the flow in the multi-strand tundish. A five-strand tundish was selected as a benchmark case. The feasibility of applying the mean age theory in the multi-strand tundish was confirmed through the benchmarking results. Thus, the proposed method can be adopted as an effective tool in finding the optimal geometry of multi-strand tundish equipped with flow control devices (FCD). KEY WORDS: mean age; residence-time distribution (RTD); tundish; design of experiment (DOE); flow control devices (FCD).

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“…To establish sufficient confidence in CFD applications, a benchmarking exercise was carried out to determine the appropriate modeling strategies for tundish simulations. 33) Mesh sizes, numerical schemes, and turbulence models were studied in detail by using the reference data from Laser Doppler Anemometry (LDA) measurements in a water model. 34) measured and calculated velocity profiles (24 points) along a line through the recirculation center on the central plane of the model.…”

Section: Model Validation and Verificationmentioning

confidence: 99%

An Integrated Workflow for Designing a Single-strand Tundish Using CFD-Taguchi Method and Mean Age Theory

Sheng

2023

ISIJ Int.

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The flow control devices (FCD) play an important role to realize the best metallurgical performance of the tundish. An integrated workflow for designing a single-strand tundish equipped with FCD is presented in this paper. Mean age theory was applied to predict the spatial mean age distributions in the tundish. Melt change efficiency (MCE) was used as a key measure to characterize the tundish's mixing performance. Taguchi method was employed to optimize the design factors, i.e. geometrical parameters of the FCD. The fluid flow and mixing of materials were analyzed based on the numerical simulations of a developed computational fluid dynamics (CFD) model. Compared to the residence time distribution (RTD) method, the mean age theory shows advantages in both numerical accuracy and efficiency. In addition, the size and location of undesired mixing zones can be easily identified which is essential for tundish design. The developed workflow that combined the CFD-Taguchi method and mean age theory can be used as an efficient tool for wide industrial applications.

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Synthesis of a CFD Benchmark Exercise: Examining Fluid Flow and Residence-Time Distribution in a Water Model of Tundish

Cited by 9 publications

References 28 publications

Effect of Flow Field Optimization of an Asymmetric Multi-Strand Tundish on the Quality Consistency of Cracking Con-Rod Steel

Effect of Flow Field Optimization of an Asymmetric Multi-Strand Tundish on the Quality Consistency of Cracking Con-Rod Steel

Application of Mean Age Theory in Multi-strand Tundish

An Integrated Workflow for Designing a Single-strand Tundish Using CFD-Taguchi Method and Mean Age Theory

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