Mixing Phenomenon and Flow Field in Ladle of RH Process

Zhang, Kaitian; Cui, Heng; Wang, Rudong; Liu, Yang

doi:10.3390/met9080886

Cited by 6 publications

(4 citation statements)

References 19 publications

(29 reference statements)

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“…Due to too much molten steel in the vacuum chamber and the expanding of the inactive layer in RH ladle however, the utilization rate of the gas driving force begins to decrease. Therefore, the mixing time starts to increase with the increase of SID [5].…”

Section: Refining the Steel In Ladlesmentioning

confidence: 99%

“…The papers covered by this Special Issue are state-of-the-art in the fields of crucial multiphase interactions in the steel making furnaces: basic oxygen furnace (BOF) [1] and electric arc furnace (EAF) [2]. Next, the research focuses on the matters related to the secondary refining processes; fluid's turbulences with nearby metal-slag interface in the ladles [3], the evolution of inclusions for Ti-bearing steels treated by calcium [4], and an influence of aluminum on flux flow in the ladle during Ruhrstahl Heraeus (RH) degassing operations [5]. Other papers are devoted to a geometry of impact area in the tundish [6], cleanliness consequences of an intermixing of the different steel grades in the tundish [7], and the reoxidation of steel from tundish cover flux [8].…”

Section: Contribution To the Special Issuementioning

confidence: 99%

“…Most of the current high-quality steels are treated under vacuum. Zhang et al [5] have used adopted particle image velocimetry (PIV) with a 1:4 scaled water model. The results of mixing simulation experiments indicated that the mixing time decreased with the increase of the gas blowing rate.…”

Section: Refining the Steel In Ladlesmentioning

confidence: 99%

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Refining and Casting of Steel

Gryc

Falkus

2020

Metals

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Section: Refining the Steel In Ladlesmentioning

confidence: 99%

Section: Contribution To the Special Issuementioning

confidence: 99%

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Refining and Casting of Steel

Gryc

Falkus

2020

Metals

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“…Except for the gas flow rate, Kishan et al [ 7 ] found that a deep snorkel immersion depth (SID) can produce a large circulation flow rate. The effect of the SID on mixing time was also investigated by Zhang et al [ 17 ] It was found that the mixing time first decreased with an increased immersion depth, while a reverse trend was found with a further increased immersion depth.…”

Section: Introductionmentioning

confidence: 98%

Study on Multiphase Flow Characteristics During RH Refining Process Affected by Nonradial Arrangement of Gas‐Blowing Nozzle

Wang

Zhou

et al. 2023

steel research int.

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Bath stirring, degassing, and decarburization in steel refining are strongly related to flow behaviors. The bubble plume produced in Ruhrstahl–Heraeus (RH) up‐snorkel plays an important role during refining, since it not only acts as a bubble pump, but also provides the reaction interface. Herein, it is aimed to form a new flow pattern in the up‐snorkel by using a nonradially arranged gas‐injection nozzle to enhance the 260 ton RH refining process. The results show that an upward spiral steel flow is produced, when nonradial gas‐injection nozzles are used in the up‐snorkel. Meanwhile, some bubbles moved toward the center region of the up‐snorkel, which may be caused by the centripetal effect in a rotational steel flow. This leads to a more uniform bubble distribution on the cross section of the snorkel, compared to that of the conventional case. Specifically, the circulation flow rate is increased by about 18.0%, and the mixing time are shortened by about 26.2% (criteria of ±5%), compared to that of the conventional case. In addition, the inclusion removal rate is increased by 0.5%, 4.8%, and 11.3% for the inclusion size of 20, 50, and 100 μm, respectively, compared to the conventional radial nozzle case.

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Water Modeling on Circulating Flow and Mixing Time in a Ruhrstahl–Heraeus Vacuum Degasser

Liu

Zhang

et al. 2021

steel research int.

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Due to the difficulties and less flexibility of industrial trials, physical modeling and mathematical modeling have been widely used to study the fluid flow phenomena during metallurgical processes, [1][2][3][4] including the multiphase fluid flow, [5][6][7] mass transfer, [8,9] chemical reaction, [10,11] bubbles and inclusions behavior, [12][13][14] and other complex phenomena in the ladle. The Ruhrstahl-Heraeus (RH) is a vital refining process to produce high-quality steel. Circulation rate [15][16][17] and mixing time, [18,19] as two significant parameters, are usually used to evaluate the refining efficiency of RH degasser, such as the melting and mixing of addition alloy. [20] In recent years, investigations on the circulating flow and the mixing phenomena during RH degassing process have been conducted to improve its refining efficiency and service life. [5,21,22] However, several investigations focused on the whole velocity distribution in the RH system using physical models. [21,23] A lot of measurement methods and empirical formulas were reported to predict the circulation rate, including the direct measurement using an intelligent velocity instrument, [24] the overflow method, [25] and the peak value method. [26][27][28] The injection gas flow rate and injection nozzles, [5] the immersion depth of snorkels, [9,[29][30][31] and the pressure in the vacuum chamber [26,32] have great influences on the circulation flow rate. Furthermore, some researchers devoted to the study on the nozzle blockage [27] refractory wear erosion, [33] or the bottom blowing [34,35] to optimize the RH refining process. The stimulus-response experiment was the usual method used to measure mixing time. The tracer was added from the feed inlet port on the vacuum chamber sidewall, and the mixing time was defined as the first time when the conductivity stabilized at AE5%, [21,36] AE3%, [37] or AE1%. [38] As the mixing time is related to the location of monitors and the fluid flow field distribution in the ladle, [6] many researchers have given out the mixing time of several points for different positions and various operation conditions. [23,39,40] However, it is difficult to figure out the mixing time distribution on the whole vertical center section in the ladle. Based on the previously reported work, some equations for calculating the mixing time are shown in Table 1. Many previous investigations indicated that the mixing time has exponential relation with the stirring power, and the range of the index of their relational expression is À0.5 to À0.3. [36,[41][42][43]

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Mixing Phenomenon and Flow Field in Ladle of RH Process

Cited by 6 publications

References 19 publications

Refining and Casting of Steel

Refining and Casting of Steel

Study on Multiphase Flow Characteristics During RH Refining Process Affected by Nonradial Arrangement of Gas‐Blowing Nozzle

Water Modeling on Circulating Flow and Mixing Time in a Ruhrstahl–Heraeus Vacuum Degasser

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