MCCR产线110 mm薄板坯结晶器流场的数值模拟

Numerical simulation of fluid flow in funnel-type mold of 110 mm thin slab in MCCR process

首钢京唐MCCR产线是国内第一条多模式连铸连轧产线,薄板坯高拉速连铸是实现无头轧制模式的基础,结晶器内流场控制是决定薄板坯高拉速连铸的关键。采用VOF两相流模型研究薄板坯连铸结晶器内流场特点,采用插钉法测量实际生产过程结晶器弯月面流速,并与对应工况条件下模拟结果进行对比校验了模型准确性。通过薄板坯连铸结晶器内流场的数值模拟仿真,获得了薄板坯高拉速条件下结晶器内钢液的流动特征。研究了连铸拉速、2种浸入式水口结构等因素对弯月面流速以及波高差的影响。结果表明:随着通钢量由3.4 t/min增加至8.2 t/min,采用四孔水口时,结晶器弯月面钢液流速由0.02 m/s增加至0.30 m/s,结晶器钢液面波高差由2.0 mm增加至7.2 mm;采用五孔水口时,结晶器钢液面波高差由0.25 m/s增加至0.5 m/s,结晶器钢液面波高差由2.6 mm增加至17.0 mm。高通钢量条件下(5.5~8.2 t/min),采用四孔水口更加有利于控制液面波动稳定性。

The Shougang Jingtang MCCR(Multi-mode Continuous Casting and Rolling)process was designed as the first domestic multi-mode thin slab continuous casting and rolling line which can continuously produce coils without cutting before the coiling machine.To guarantee material balance between casting and rolling processes,high throughput operations of thin slab caster should be achieved.A stabilized mold level is one of the critical technologies needed to achieve stable casting operation for high throughput operations.A 3 D two phase mathematical model was carried out to investigate the fluid flow characteristics in the mold under high throughput conditions,the pin method was used to measure the flow velocity of the mold meniscus in the actual production process,and the simulation results were compared with the corresponding operating conditions to verify the accuracy of the model.Through the numerical simulation of the flow field in the thin slab continuous casting mold,the flow characteristics of the molten steel in the mold under the condition of high drawing speed of the thin slab were obtained.The effects of continuous casting speed and two types of submerged nozzle structures on the velocity of the meniscus and the wave height difference were studied.According to the numerical simulation results,when liquid steel is fed into the funnel mold with 4-ports SEN,the meniscus flow velocity increases from 0.02 m/s to 0.30 m/s and max span of meniscus level increases from 2.0 mm to 7.2 mm as the throughput increases from 3.4 t/min to 8.2 t/min.Feeding liquid steel into the funnel mold with 5-ports SEN,the meniscus flow velocity increases from 0.25 m/s to 0.50 m/s and max span of meniscus level increases from 2.6 mm to 17.0 mm as the throughput increases from 3.4 t/min to 8.2 t/min.Under the condition of specific high throughput conditions of 5.5-8.2 t/min,the use of four-hole nozzle is more conducive to controlling the stability of liquid level fluctuations.