吹氩钢包内气泡聚并破碎和运动行为
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摘要
基于Euler-Euler双流体模型及PBM模型,建立了吹氩钢包流场数学模型.此模型考虑了吹氩钢包内气液两相之间的曳力、升力、湍流扩散力和气泡的聚并和破碎等因素.研究了气泡聚并破碎对钢包钢液内含气率、气泡速度和混匀时间的影响,并与定气泡直径下的流场进行对比.数值结果表明:PBM模型的预测值更接近实验结果;钢包内气泡分布为中心区域气泡直径大,从中心到气液边界处气泡直径逐渐减小,气液两相区边界处直径最小;在钢包轴线上气泡速度先急剧增加然后缓慢减小,在接近液面处气泡速度又急剧减小.
A mathematical model for the gas-liquid flow field in the ladle with argon blowing was built based on the Euler-Euler model and population balance model( PBM),which considered the effects of the drag force,lift force,turbulent dispersion force and bubble coalescence and breakage in ladle with argon blowing. The effects of bubble coalescence and breakage on the gas holdup,bubble velocity and mixing time were investigated and further compared with those from the constant diameter model. The numerical results show that the predicted data of the PBM agrees well with the experimental one. The bubble diameter is the largest one in center area and reduces gradually from the center to the gas-liquid interface,therefore it becomes the smallest one at gasliquid interface in the ladle. At the ladle central axis,the bubble velocity firstly increases drastically and then decreases gradually,however,it decreases greatly near the free surface.
A mathematical model for the gas-liquid flow field in the ladle with argon blowing was built based on the Euler-Euler model and population balance model( PBM),which considered the effects of the drag force,lift force,turbulent dispersion force and bubble coalescence and breakage in ladle with argon blowing. The effects of bubble coalescence and breakage on the gas holdup,bubble velocity and mixing time were investigated and further compared with those from the constant diameter model. The numerical results show that the predicted data of the PBM agrees well with the experimental one. The bubble diameter is the largest one in center area and reduces gradually from the center to the gas-liquid interface,therefore it becomes the smallest one at gasliquid interface in the ladle. At the ladle central axis,the bubble velocity firstly increases drastically and then decreases gradually,however,it decreases greatly near the free surface.
引文
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[2]Alexiadis A,Gardin P,Domgin J F.Spot turbulence,break-up and coalescence of bubbles released from a porous plug injector into a gas-stirred ladle[J].Metallurgical and Materials Transactions B,2004,35(5):949-956.
[3]Alexiadis A.Bubble dispersion patterns in bubbly-flow released from a porous plug into a gas-stirred ladle[J].Applied Mathematical Modelling,2007,31(8):1534-1547.
[4]Aniruddha M,Eric W G,Kumar D,et al.Detailed modeling of gas flow in liquid steel:bubble size distribution and voidage calculation[J].Steel Research International,2005,76(1):22-32.
[5]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 International,2015,55(7):1337-1446.
[6]Schiller L,Naumann Z.A drag coefficient correlation[J].VDI Zeitung,1935,77:318-320.
[7]Tomiyama A.Struggle with computational bubble dynamics[J].Multiphase Science and Technology,1998,10(4):369-405.
[8]Simonin O,Viollet P L.Predictions of an oxygen droplet pulverization in a compressible subsonic coflowing hydrogen flow[J].Numerical Methods for Multiphase Flows,1990,91(2):65-82.
[9]Fluent Inc.Fluent 14.0 user manual[EB/OL].[2016-07-16].https://zh.scribd.com/doc/140163383/Ansys-fluent-14-0-Users-Guide.
[10]Luo H.Coalescence,breakup and liquid circulation in bubble column reactors[D].Trondheim:Norwegian Institute of Technology,1993.
[11]Luo H,Svendsen H F.Theoretical model for drop and bubble breakup in turbulent dispersions[J].AICh E Journal,1996,42(5):1225-1233.
[12]Hsiao T C,Lehner T,Kjellberg B.Fluid flow in ladles—experimental results[J].Scandinavian Journal of Metallurgy,1980,9(3):105-110.