Optimization of Argon Bottom Blowing During Electric Heating Stage of LF Refining Process

doi:10.12068/j.issn.1005-3026.2024.04.007

Abstract

Abstract:

During the electric heating stage of the LF （lalde furnace） refining process， dual?nozzle equi?flow argon blowing is often used. This paper proposes a bottom blowing method of dual?nozzle non?equi?flow argon blowing. A 1∶4 non?isothermal water model experimental platform was designed based on a 135 t ladle in a steel plant. Under the same total flow rate， temperature homogenization experiments were conducted with bottom blowing ratios of 1∶1， 2∶1 and 3∶1. The results show that the minimum dimensionless temperature difference and the best homogenization effect were observed at each monitoring point when the bottom blowing ratio was 2∶1. The coupling mathematical model for flow and heat transfer was established to verify the experimental results. The results show that under the same total flow rate， the proportion of flow dead zone was 14.1%， 9.1%， and 9.8% respectively when the bottom blowing ratio was 1∶1， 2∶1 and 3∶1， and the proportion of temperature dead zone was 6.2%， 2.6%， and 0.3%， respectively. The 2∶1 non?equi?flow bottom blowing method has advantages in active flow field and promotes the temperature uniformity.

Key words: non?equi?flow argon blowing, bottom blowing distribution, temperature homogenization, non?isothermal water model, flow dead zone

CLC Number:

TF 777

Ning WANG, De-yue QIN, Bao-kuan LI, Jia-qi ZHAO. Optimization of Argon Bottom Blowing During Electric Heating Stage of LF Refining Process[J]. Journal of Northeastern University(Natural Science), 2024, 45(4): 507-513.

Figures/Tables 14

Fig.1 Schematic diagram of LF

Table 1 Basic parameters of ladle water model

参数	数值
钢包高度/mm	796
底部直径/mm	667
顶部直径/mm	685
钢液深度/mm	746
渣层厚度/mm	45
喷嘴直径/mm	25
入口偏离中心距离/mm	104.5
喷嘴夹角/（°）	117
底部喷嘴中心间距/mm	358

Fig.2 Schematic diagram of argon inlet position at ladle bottom

Table 2 Scheme of bottom blowing flow rate

方案编号	Inlet-1流量/（L·h^-1）	Inlet-2流量/（L·h^-1）	流量比	总流量/（L·h^-1）
1	112.5	112.5	1∶1	225
2	150	75	2∶1	225
3	168.75	56.25	3∶1	225

Fig.3 Schematic diagram of water model experiment device

Table 3 Physical parameters for ladle

参数	数值
水密度/（kg·m^-3）	1 000
水黏度/（kg·m^-1·s^-1）	0.001
油层密度/（kg·m^-3）	850
油层黏度/（kg·m^-1·s^-1）	0.008 5
水-氩气表面张力/（N·m^-1）	0.073
初始水温度/K	285
氩气密度/（kg·m^-3）	1.67

Fig.4 Grid division

Fig.5 Dimensionless temperature curves without bottom blowing bottom blowing of 225 L/h total flow rate

Fig.6 Dimensionless temperature curves with

Fig.7 Velocity field at total flow rate of 225 L/h

Fig.8 Volume fractions of flow active zone and dead zone in the water model

Fig.9 Temperature distribution on different sections at total flow rate of 225 L/h

Fig.10 Volume fraction of temperature dead zone at total flow rate of 225 L/h

Fig.11 Temperature distribution at the same section with a total flow rate of 225 L/h

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