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Simulation of Gas-Liquid Two-Phase Flow and Mixing Phenomena During RH Refining Process |
Chang LIU, Shusen LI, Lifeng ZHANG( ) |
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China |
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Cite this article:
Chang LIU, Shusen LI, Lifeng ZHANG. Simulation of Gas-Liquid Two-Phase Flow and Mixing Phenomena During RH Refining Process. Acta Metall Sin, 2018, 54(2): 347-356.
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Abstract The Ruhrstahl-Heraeus (RH) vacuum system is vitally important in the secondary refining process since it is highly effective on decarburization and degassing, which involves complex multiphase flow and transport phenomena. Many investigations on the flow field in the RH refining process have been reported. However, only several investigations are focused on the bubble expansion in the up-leg snorkel. In this work, the combined mathematical model and physical model were employed to simulate the fluid flow and mixing phenomena in the RH reactor. A water model for a practical 210 t RH reactor was established according to similitude principle, and the flow field on the center section of the physical model was captured by PIV (particle image velocimetry) system. The coupled VOF (volume of fluid) model and DPM (discrete phase model) were used to simulate the multiphase fluid flow in the RH reactor. Both the k-ε model and LES (large eddy simulation) model were performed to describe the turbulent characteristics during the RH refining process. The mathematical model was validated by the water model with the same experimental conditions. It suggests that the calculated results show a good agreement with the measured one. Based on the LES model, the instantaneous velocity distribution and the generate and the dissipate of vortex were computed. Also, the mixing time of different position in the ladle was measured and calculated. The results show that the mixing time near the up-leg snorkel is larger than that near the down-leg snorkel. A model for bubble expansion was developed and used to simulate the bubble behavior in the steel-argon system. The results show that the bubble expansion has a strong impact on the flow field in the RH reactor.
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Received: 16 October 2017
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Fund: Supported by National Natural Science Foundation of China (Nos.51725402, 51504020 and 51704018) and National Key R&D Program of China (Nos.2017YFB0304000, 2017YFB0304001 and 2016YFB0300102) |
[1] | Park Y G, Yi K W.A new numerical model for predicting carbon concentration during RH degassing treatment[J]. ISIJ Int., 2003, 43: 1403 | [2] | Zhang L F, Li F.Investigation on the fluid flow and mixing phenomena in a Ruhrstahl-Heraeus (RH) steel segasser using physical modeling[J]. JOM, 2014, 66: 1227 | [3] | Maas H, Hupfer P.The significance of the circulation rate on the vacuum treatment of liquid steel with the RH process[J]. Vacuum, 1969, 19: 199 | [4] | Asai S, Okamoto T, He J C, et al.Mixing time of refining vessels stirred by gas injection[J]. ISIJ Int., 1983, 23: 43 | [5] | Tsujino R, Nakashima J, Hirai M, et al.Numerical analysis of molten steel flow in ladle of RH process[J]. ISIJ Int., 1989, 29: 589 | [6] | Ling H T, Li F, Zhang L F, et al.Investigation on the effect of nozzle number on the recirculation rate and mixing time in the RH process using VOF+DPM model[J]. Metall. Mater. Trans., 2016, 47B: 1950 | [7] | Chen G J, He S P, Li Y G.Investigation of the air-argon-steel-slag flow in an industrial RH reactor with VOF-DPM coupled model[J]. Metall. Mater. Trans., 2017, 48B: 2176 | [8] | Kishan P A, Dash S K.Prediction of circulation flow rate in the RH degasser using discrete phase particle modeling[J]. ISIJ Int., 2009, 49: 495 | [9] | Zhang J M, Liu L, Zhao X Y, et al.Mathematical model for decarburization process in RH refining process[J]. ISIJ Int., 2014, 54: 1560 | [10] | Geng D Q, Zheng J X, Wang K, et al.Simulation on decarburization and inclusion removal process in the Ruhrstahl-Heraeus (RH) process with ladle bottom blowing[J]. Metall. Mater. Trans., 2015, 46B: 1484 | [11] | Chen G J, He S P, Li Y G, et al.Investigation of gas and liquid multiphase flow in the Rheinsahl-Heraeus (RH) reactor by using the euler-euler approach[J]. JOM, 2016, 68: 2138 | [12] | Neves L, De Oliveira H P O, Tavares R P. Evaluation of the effects of gas injection in the vaccum chamber of a RH degasser on melt circulation and decarburization rates[J]. ISIJ Int., 2009, 49: 1141 | [13] | Jiang F, Cheng G.Effects of gas injection with multihole orifices in upleg snorkel on bubble behaviour and decarburisation rate during RH refining[J]. Ironmaking Steelmaking, 2012, 39: 386 | [14] | Li L M, Liu Z Q, Li B K, et al.Water model and CFD-PBM coupled model of gas-liquid-slag three-phase flow in ladle metallurgy[J]. ISIJ Int., 2015, 55: 1337 | [15] | Park Y G, Doo W G, Yi K W, et al.Numerical calculation of circulation flow rate in the degassing Rheinstahl-Heraeus process[J]. ISIJ Int., 2000, 40: 749 | [16] | Szekely J, Fang S D.Studies in vacuum degassing: Mass and momentum transfer to gas bubbles rising in melts, the freeboard of which is evacuated[J]. Metall. Trans., 1974, 5: 1429 | [17] | Ajmani S K, Dash S K, Chandra S, et al.Mixing evaluation in the RH process using mathematical modelling[J]. ISIJ Int., 2004, 44: 82 | [18] | Geng D Q, Lei H, He J C.Effect of traveling magnetic field on flow, mixing, decarburization and iinclusion removal during RH refining process[J]. ISIJ Int., 2012, 52: 1036 | [19] | Li L M, Liu Z Q, Cao M X, et al.Large eddy simulation of bubbly flow and slag layer behavior in ladle with discrete phase model (DPM)-volume of fluid (VOF) coupled model[J]. JOM, 2015, 67: 1459 | [20] | Sahai Y, Emi T.Criteria for water modeling of melt flow and inclusion removal in continuous casting tundishes[J]. ISIJ Int., 1996, 36: 1166 | [21] | Aoki J, Zhang L, Thomas B, et al.Modeling of inclusion removal in ladle refining [A]. ICS 2005-The 3rd International Congress on the Science and Technology of Steelmaking[C]. Warrendale: Association for Iron & Steel Technology, 2005: 319 | [22] | Chen G J, He S P, Li Y G, et al.Modeling dynamics of agglomeration, transport, and removal of Al2O3 clusters in the RH reactor based on CFD-PBM coupled model[J]. Ind. Eng. Chem. Res., 2016, 55: 7030 | [23] | Sano M, Mori K, Fujita Y.Dispersion of gas injected into liquid metal[J]. Tetsu Hagané, 1979, 65: 1140(佐野正道, 森一美, 藤田康久, 溶融金属中ガス吹込みにおける気泡の分散[J]. 鉄と鋼, 1979, 65: 1140) | [24] | Liao Y X, Lucas D.A literature review of theoretical models for drop and bubble breakup in turbulent dispersions[J]. Chem. Eng. Sci., 2009, 64: 3389 | [25] | Liao Y X, Lucas D.A literature review on mechanisms and models for the coalescence process of fluid particles[J]. Chem. Eng. Sci., 2010, 65: 2851 | [26] | Zhang L, Taniguchi S.Fundamentals of inclusion removal from liquid steel by bubble flotation[J]. Int. Mater. Rev., 2000, 45: 59 | [27] | Zhu M Y, Inomoto T, Sawada I, et al.Fluid flow and mixing phenomena in the ladle stirred by argon through multi-tuyere[J]. ISIJ Int., 1995, 35: 472 | [28] | Wei J H, Yu N W, Fan Y Y, et al.Study on flow and mixing characteristics of molten steel in RH and RH-KTB refining processes[J]. J. Shanghai Univ. Engl. Ed., 2002, 6: 167 |
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