180 t转炉聚合射流流场的水力学模型的实验研究

采用几何相似比1∶10水模型对180 t顶底复吹转炉内射流与熔池相互作用进行模拟试验,研究了在最佳枪位(150 mm)时氧气流量(38~42 m³/h)对均混时间的影响以及最佳顶枪流量(39 m³/h)下聚合射流氧枪枪位(40~150 mm)对均混时间的影响。结果表明,聚合射流氧枪对熔池的搅拌效果完全能达到顶底复吹的搅拌效果,如能在转炉冶炼工艺中应用,可取消底吹系统,简化转炉设备,提高转炉炉龄。     

大型转炉高供氧强度吹炼的水模实验

为使大型转炉的生产率达到国际先进水平,在300~350t大型氧气转炉上实现4.0~5.0m3/(t·min)的高供氧强度吹炼,设计了新的大流量氧枪喷头,并在1∶10的有机玻璃模型上进行氧射流与熔池作用的水模实验。水模实验大流量氧枪喷头的主要参数为:喷头孔数6~8个,采用双角度交错布置,喷孔倾角10°~17°,喷孔出口马赫数2.0~2.2。同时测定了枪位高度为1.8~2.6m时的熔池喷溅率、混匀时间和穿透深度。研究结果表明,大流量新喷头的喷溅量和射流对熔池的穿透深度都在转炉正常吹炼范围内,熔池混匀时间平均缩短6s,泡沫渣可将喷溅率降低50%。大流量新喷头良好的吹炼性能为大型转炉高供氧强度吹炼的氧枪喷头设计提供了可靠的数据。     

180 t转炉超音速射流和聚合射流与炼钢熔池作用的水模型实验研究

以鞍钢180 t顶底复吹转炉为原型,设计超音速氧枪喷头进行了复吹转炉传统射流与聚合射流对熔池相互作用的水力学模型实验。超音速射流水模实验确定最佳的均混时间为12.6 s;在保持最佳顶吹气体流量的条件下,以降低枪位模拟聚合射流对熔池的相互作用。结果表明:当氧枪枪位下降到40 mm时,均混时间为11.8 s,这说明聚合射流完全可以达到传统射流对熔池的搅拌效果,可取消底吹系统,简化转炉设备和提高转炉炉龄。     

Bath mixing behaviour in top–bottom–side blown converter

Abstract

The influence of blowing process parameters on bath stirring was investigated in a model of a top–bottom–side blown converter using physical modelling experiments. It was shown that the side blowing gas flowrate has an important influence on bath mixing time which decreases as side tuyere gas flowrate increases up to a critical flowrate and then plateaus. Bottom gas injection is favourable for bath mixing for top–bottom–side blown converters; however, top lance height, top gas flowrate and bath level have little influence.     

180 t转炉底吹和顶-底复吹射流与熔池作用的水模型研究

根据180 t转炉的实际生产情况,以修正的Froude准数为相似准数,建立几何相似比10 ： 1水模型,进 行了四孔对称单纯底吹试验,并在最佳的底吹工艺参数下(底吹最佳位置为喷嘴所在同心圆直径:转炉熔池直径= 0. 3处;最佳流量为0. 7 m³/h,均混时间18. 2 s),通过改变顶吹氧枪的气体流量和吹炼枪位进行了顶底复吹转炉射 流与熔池作用的试验。结果表明,在底吹条件下,增加顶吹工艺(最佳枪位150 mm,最佳流量39 m³/h),熔池平均 的均混时间减少了 5.6 s, 180 t转炉顶底复吹可显著提高经济效益。     

CAS喷粉精炼熔池混合行为的水模型试验

通过1:4水模型装置模拟150 t CAS钢包精炼过程熔池内流场特征和渣面裸露情况,以确定最佳的喷吹位置和研究喷吹参数对熔池均混时间的影响。结果表明,喷吹气量和底吹流量越大,喷枪插入越深,浸渍罩插入越浅,则均混时间越短;底吹位置离钢包中心越近,均混效果越差。分析得出,150 t CAS钢包增加喷粉后,最佳底吹位置为离钢包中心0.35R(R为钢包下口半径)处。     

RH喷吹参数对循环流量和均混时间影响的物理模拟

以某厂300tRH真空精炼装置为研究原型,建立1∶6.5的水力模型对RH喷吹精炼工艺进行物理模拟。研究了喷吹位置、喷吹气量及驱动气体流量对循环流量和均混时间的影响。结果表明:不同喷吹气量、驱动气体流量条件下,获得大循环流量和短均混时间的最优喷吹位置不同。较小的喷吹气量(2.98~3.53m3/h)或者较小的驱动气体流量(0.93~1.02m3/h)时,宜采用低顶枪枪位(153.8mm)喷吹;喷吹气量大于3.91m3/h或者驱动气体流量大于1.12m3/h时,宜采用真空槽底部喷吹角度120°的侧喷嘴喷吹。顶枪与侧喷嘴复合喷吹有利于提高RH喷吹工艺的适应性及循环效率。     

复吹转炉顶吹枪位与非均衡底吹搅拌的水模拟

为优化120 t复吹转炉冶炼效果,通过水模型试验,模拟研究了复吹转炉底吹强度、顶枪枪位、底吹排布方式和流量分配比对渣 钢间传质效果和熔池混匀时间的影响。研究表明,在相同底吹条件下,顶枪低枪位操作时渣 钢间传质系数比高枪位操作时渣 钢间传质系数大,且随着底吹流量分配比增大,渣 钢间传质系数先增大后减小。在相同顶枪枪位操作条件下,底吹元件间隔排布时,渣 钢界面传质效果总体优于连续排布。随着底吹流量分配比增大,高枪位和低枪位混匀效果变化趋势近似相反。在高枪位下,底吹元件连续排布混匀时间总体少于底吹元件间隔排布时对应的混匀时间;在顶枪低枪位操作条件下,底吹元件连续排布混匀时间总体大于间隔排布混匀时间。通过顶枪枪位、底吹排布和流量分配比的合理匹配,较传统均衡流量底吹模式,传质系数可提高30%～125%,混匀时间可减少8.6%～51.5%。     

Physical simulation of converter steelmaking with powder injection

A water model of top and bottom blown converter with top lance powder injection and bottom tuyere powder injection was established to investigate the powder injection. The results show that the powder penetration ratio under the condition of top lance injection is greater than that under the condition of bottom tuyere powder injection. In both cases, the powder penetration ratio increases with the increase of solid/gas ratio and powder particle size. Powder uniform dispersion time with top lance powder injection is longer than that with bottom tuyere powder injection. Top lance powder injection, lance height of 258?mm, bottom blowing rate of 1·96?Nm³?h^?1 and powder particle size of 0·212–0·380?mm are suggested as the optimum powder injection operation under the experimental condition. The corresponding optimum operation for prototype is top lance powder injection with lance height of 1550?mm, powder size of 1–5?mm and bottom blowing rate of 450?Nm³?h^?1.     

Preliminary Investigation of Fluid Mixing Characteristics during Side and Top Combined Blowing AOD Refining Process of Stainless Steel

The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon‐oxygen decarburization) refining process of stainless steel were preliminarily investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model were more reasonably determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics was examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a high mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from the top lance made the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main‐tuyeres and sub‐tuyeres and top lance, the angle between each tuyere, and the tuyere number were evaluated.     

300 t复吹转炉底吹系统优化模拟

顶底复合吹炼转炉炼钢法是当下主流的炼钢方法,底部供气元件的种类、支数、排布方式和底吹供气强度直接影响着转炉熔池的混匀效果,合理的流场不仅可以降低生产成本,更能缩短冶炼周期,增加企业效益.基于冷态水模拟以及CFD数值模拟手段各自的研究特点,以某钢厂300 t转炉为原型,将不同底吹条件下熔池的混匀时间、死区以及弱流区体积作...     

重钢85t复吹转炉的水模型试验

通过重钢85 t复吹转炉1∶8的水模型,试验研究了顶枪枪位、底吹流量对转炉熔池混匀时间、炉口喷溅量、冲击深度和液面扰动的影响。实验表明,模型获得最大搅拌能的顶枪枪位为50~100 mm;枪位在90~110 mm时,由射流冲击引起的物理喷溅量达到最大值。建立了重钢85 t转炉复吹工艺参数:冶炼前期顶枪枪位为1600~1760 mm,底吹流量240~350 m³/h;中期两参数分别为1100~1300 mm和160~200 m³/h,后期两参数分别为1040~1120 mm和200~350 m³/h。     

唐钢50 t复吹转炉水模型的实验研究

针对唐钢50 t复吹转炉,采用1:6.35水模型的正交试验,研究了氧枪枪型、枪位、顶吹流量和底吹流量对熔池混匀时间、穿透深度、冲击面积和喷溅量的影响。结果表明,与4孔氧枪相比,使用改进后的4孔变角氧枪可增加对熔池的冲击面积,降低穿透深度和炉口溅出量,缩短混匀时间。对于50 t复吹转炉实际枪位≤1.3 m,有利于缩短冶炼时间,提高冶炼强度;顶吹流量控制在13 000～14000 m³/h,可缩短混匀时间和减少炉口溅出量。     

300t 顶底复吹转炉氧枪枪位的水模型研究和应用

研究了300t顶底复吹转炉1:10几何相似比的水模型顶枪枪位（150~230mm）和流量（44~48m³/h）对钢液混匀时间的影响。模拟结果得出,最佳枪位为170mm,最佳流量为45m³/h。钢厂300t顶底复吹转炉应用结果表明,顶吹流量60000m³/h和底吹流量1000m³/h时,当顶枪枪位由1900mm改进为1700mm时,碳氧积平均值由原来的27.94降为23.49,提高了转炉内熔池的搅拌效果,吹炼时间由原15.8min降低至15.5min,降低了生产成本。     

复吹转炉底吹氧气和石灰粉水模拟

 为了考察复吹转炉底吹氧气和石灰粉过程中的熔池特性,建立复吹转炉底吹喷石灰粉的水模型,用水模拟铁水,用空心玻璃微珠模拟石灰粉。利用图像处理法研究了底吹氧气和石灰粉时粉剂分布情况及熔池搅拌情况。采用熔池电导率法考察了相同条件下底吹喷粉与不喷粉时的混匀时间。研究结果表明,喷粉能够促进熔池搅拌,且粉剂扩散速度随底吹载气流量增大而增大;未喷粉时,混匀时间随载气流量增大而减小;在相同底吹载气流量条件下,喷粉时熔池的混匀时间明显低于未喷粉时的混匀时间,且在试验范围内,混匀时间在底吹载气流量为2 m3/h(标准态)时出现极小值。     

转炉超音速氧枪喷头磨损后的吹炼特性变化

 转炉氧枪喷头会随枪龄的增加发生不同程度的侵蚀,为了探究氧枪喷头侵蚀程度对超音速气体射流吹炼特性的影响,建立了120 t转炉及超音速氧枪的三维全尺寸几何模型,研究了氧枪喷头不同磨损角度对气体射流特性、熔池速度及壁面侵蚀的影响。发现随着磨损角度增加,射流速度衰减加快,射流核心区长度缩短,同一等速线长度缩短,射流中心最大速度和最大速度点距中心距离增大。射流动压衰减速度随磨损角度增加而加快,磨损角度由0增至20°,距喷头端面1.5 m处最大动压减小了14.84%,14 000 Pa等压线包围面积由0.038 m2减小至0.002 m2。钢液面处高速区面积随着磨损角度增加而减小,死区面积随着磨损角度增加而增大。熔池纵截面高速区域主要分布在冲击凹坑和底吹元件附近,低速区域主要分布在熔池底部,死区主要分布在熔池底部中心和炉壁下部区域。当熔池深度小于0.6 m时,顶吹气流对熔池的搅拌起主要作用,磨损角度增加,熔池搅拌能力变弱,熔池横截面高速区面积减小,低速区和死区面积增大;当熔池深度大于0.6 m时,底吹气流对熔池搅拌起主要作用,高速区面积基本不变。渣-金作用区域和底吹流股附近流体湍动能较大、壁面剪切应力较为集中,该部位耐火材料侵蚀严重。熔池壁面附近流体湍动能和壁面剪切力随磨损角度增加而降低,转炉炉衬侵蚀速度减小。     

Water modelling study of fluid flow and mixing characteristics in bath during AOD process

Abstract

The fluid flow and mixing characteristics in the bath during the argon–oxygen decarburisation (AOD) process have been investigated on a water model of an 18 t AOD vessel blown through two annular tube type lances of constant cross-sectional area. The geometric similarity ratio between the model and its prototype (including the lances) was 1 : 3. Based on theoretical calculations of the parameters of the gas streams in the lances, the gas blowing rates used for the model were determined fairly precisely. Thus, sufficiently full kinematic similarity between the model and its prototype was ensured. The influence of the gas flowrate and the angle included between the two lances was examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during blowing, and there was no obvious dead zone in the bath, resulting in excellent mixing and a short mixing time. The gas flowrates, particularly that of the main lance, had a key influence on these characteristics. However, the gas jet of the sublance had a physical shielding effect on the gas jet of the main lance, and mixing efficiency could be improved by a suitable increase in the gas blowing rate of the sublance. The angular separation of the two lances also had a marked influence on the flow and mixing in the bath. An excessively large or small separation of the two lances would reduce the stability of blowing and would also be unfavourable to mixing. The optimum range of separation is 60–100° under the conditions of the present work. The relationships between the mixing time and the gas blowing rate, the stirring energy, the modified Froude numbers for the main lance and sublance, the lance arrangement, etc. have been obtained.     

自旋转氧枪对熔池混匀时间影响的冷态模拟

摘要：针对传统氧枪对熔池搅拌能力有限,无法高效冶炼磷含量较高铁水的问题,设计一种新型自旋转氧枪,并建立了相应的冷态模拟系统,对比研究了自旋转氧枪与传统氧枪对熔池混匀时间的影响规律。结果表明,随着顶吹、底吹流量的提高以及枪位的下降,熔池混匀时间均缩短;自旋转氧枪对熔池的搅拌效果明显优于传统氧枪,熔池流场更加均匀;转速分别为0、3.14～5.23、7.33～9.42、11.51～13.61rad/s时,混匀时间分别降低12.0%、23.8%、24.4%、8.1%;能量密度的变化对混匀时间的影响小于传统氧枪。     

RH-PTB真空精炼装置内粉剂混合特性的水模型研究

根据相似理论,用1∶9水模型钢包(直径0.43m,水面高度0.45m)模拟RH-PTB真空精炼水冷顶枪喷粉技术,研究顶枪气量、上升管提升气量、顶枪枪位高度对粉剂混均时间的影响。结果表明,随顶枪气量增加,粉剂在液体中均混时间增加,并具有最大值;随提升气量增加,均混时间迅速减少,但当提升气量≥15L/min时,均混时间不再继续减少;顶枪枪位对均混时间有一定影响,实际操作中,应根据具体情况,调整顶枪枪位,以减少粉剂均混时间。     

Cold Simulation of Oxygen Transfer Rate in BOF

 By measuring the mass transfer coefficient of between water and oil, the oxygen transfer rate of bath in the BOF smelting process is researched, and the influence of top and bottom blowing gas flow rate on the mechanism of mass transfer between metal and slag is discussed. The results show that when the bottom blowing gas flow rate increases on the conditions of top blowing, the mass transfer rate evidently increases, and the influence ratio of top blowing on the mass transfer is 10 percent of bottom blowing; The relation among top gas flow rate, bottom gas flow rate and lance height are established by the stirring power density. The equation between the mass transfer coefficient between metal and slag is formed, which furnishes reference for optimizing process parameters of BOF. The relation between the emulsification ratio between water and oil and the bottom blowing gas flow rate on the condition of top and bottom blowing is obtained. The result shows that with the increase of the bottom blowing gas flow rate the emulsification ratio increases in linearity, which increases the mass transfer rate of benzoic acid between water and oil.