搅拌器磨损对KR法脱硫搅拌效果的数值分析

为探究三叶搅拌器在铁水腐蚀下对铁水搅拌流场的影响,参考传统KR脱硫搅拌工艺过程,利用仿真软件,采用多重参考系法(MRF)及VOF模型,研究了不同磨损程度对三叶搅拌器的搅拌流场与液面状况的影响规律.结果表明:相同搅拌工艺参数条件下,随着搅拌器磨损程度R的增大,搅拌铁水平均流速和平均湍动能降低,搅拌漩涡深度减小,对搅拌流场...     

基于KR法新型脱硫搅拌器的流场数值分析

为改进铁水预处理脱硫设备和工艺,提高脱硫效率,参考传统KR脱硫法,将搅拌器与喷枪的优点结合,形成了一种既搅又喷的新型搅拌器。应用Fluent软件,采用Eulerian模型对铁水罐内的流场进行数值分析,从流场速度和气体分布等方面研究了搅拌器不同的偏心度、搅拌转速、通气流量对铁水罐内脱硫效果的影响。结果表明:采用新型搅拌器,可增强流场的流动,由搅拌器底部喷嘴喷出的脱硫气体作螺旋上升运动,会使脱硫气体在铁水罐中分布范围更广且更加均匀;新型搅拌器在搅拌转速为150 r/min、通气流量为5.0 m~3/h和偏心度为0.3时,气体的分布和密集程度最佳,流场具有较大的平均流速,有利于铁水与脱硫剂的反应。     

KR法中桨叶结构对搅拌效率影响的数值模拟研究

KR法是铁水预处理中主流的脱硫方法。采用数值模拟方法研究了正四叶桨、螺旋三叶桨和双层正四叶桨三种桨叶的搅拌效率,结果表明：双层正四叶桨的混匀时间比正四叶桨短7.3%,比螺旋三叶桨短37.9%;通过对铁水中轴向速度、湍动能分布的分析发现,双层正四叶桨搅拌器中铁水轴向速度更大,并且铁水中湍动能广泛扩散,双层正四叶桨的平均湍动能比正四叶桨大28%,比螺旋三叶桨大1.8%。     

100t铁水罐下KR搅拌法脱硫流场的数值模拟

基于Fluent软件对直径2.8 m、搅拌桨高0.75 m、铁水高度3.1 m的100 t铁水罐KR脱硫进行数值模拟,得到铁水罐内铁水的流动状态及速度分布。通过对搅拌桨直径0.7～1.1 m,浸入深度1.00～1.34 m和搅拌转速60～140 r/min下的流场和湍动能进行对比分析,得出最佳的工况为:搅拌转速120 r/min、浸入深度1.34 m、搅拌桨直径0.9 m。通过工艺实践,铁水脱硫率达到96%以上。     

喷吹颗粒镁铁水脱硫影响因素的数值模拟

在CFD软件平台上进行了青钢新区喷吹颗粒镁铁水脱硫影响因素的数值模拟,研究了载气流量、喷枪插入深度、喷嘴直径、喷嘴夹角对脱硫过程铁水罐内流场以及混匀死区的影响。结果表明,在原有工艺参数下,随载气流量适当减小、喷枪插入深度最大、喷嘴直径稍微增大和喷嘴夹角适当增大,均可改善铁水罐内速度场和湍动能的分布,减小混匀死区,增加停留时间。推荐的工艺参数为载气流量90 Nm~3/h、喷枪插入深度200 mm、喷嘴直径8 mm、喷嘴夹角60°~90°。     

KR法脱硫气液两相流的数值模拟与水模型试验

采用CFD软件Fluent中标准k-湍流模型和VOF多相流模型对KR法铁水脱硫过程中气液两相流进行了模拟,研究了搅拌器浸入深度与搅拌速度对漩涡和液相流场的影响,数值模拟结果与水模型试验结果基本吻合。研究结果表明:随着搅拌速度增加漩涡深度逐渐加大,搅拌器浸入过浅容易发生"卷气"现象;搅拌速度由120r/min增大到200r/min时,铁水平均速度增大约83%,铁水内部形成不规则流动,且轴向流动明显增强;搅拌器浸入深度为187.5mm时,轴向上铁水平均速度差最大,为0.132m/s,大速度差有利于脱硫剂的卷入;搅拌速度为160r/min时,高流速铁水所占体积比大。     

基于氧枪喷头磨损的熔池搅拌特性

研究氧枪喷孔出口磨损程度对射流动力学参数及熔池搅拌效果的影响可以为氧枪喷头设计和冶炼工艺优化提供理论支持。建立了0°、10°和20°磨损角度氧枪自由射流几何模型,分析了喷孔出口磨损程度对射流轴向和径向动力学参数分布的影响,发现入口压力相同时,喷孔出口磨损程度增大,射流速度、动压和马赫数衰减加快,射流聚合程度增强。在喷孔出口0.18 m范围内,磨损后氧枪的湍动能大于未磨损氧枪,且磨损程度越大,射流湍动能越大。超过此范围后,未磨损氧枪湍动能大于磨损后氧枪。在喷孔出口1 000 mm处,射流径向最大速度、动压、马赫数和湍动能均随着喷孔出口磨损程度的增大而减小。建立了120 t转炉和5孔氧枪1∶4水力学试验模型,研究了枪位和气体流量变化对不同磨损程度氧枪冲击效果和混匀时间的影响,分析了枪位和气体流量相同时氧枪喷孔出口磨损对熔池流场的影响。发现气体流量相同时,随着枪位升高,熔池冲击深度减小,冲击直径增大,混匀时间增大。枪位相同时,随着气体流量增大,熔池冲击深度和冲击直径增大,混匀时间减少。枪位和气体流量相同时,喷孔出口磨损程度增大,冲击深度和冲击直径减小,混匀时间增大,高锰酸钾溶液完全扩散时间增...     

铁水喷吹含铁粉剂脱硅的实践

利用混铁炉倒铁水的自然搅拌动能,将含铁粉剂喷入剧烈搅拌的铁水中,由于良好的还原气氛和搅拌,粉剂中的铁元素近100%还原,铁水中的Si得到部分脱除。铁水喷吹脱硅技术采用自动化控制,实现了"一键"式操作,并在济南钢铁股份公司第一炼钢厂50t铁水包上成功应用,为钢铁厂含铁粉尘的利用提供了技术支持。     

铁水喷吹脱硅及铁粉还原技术的开发及应用

利用混铁炉倒铁水的自然搅拌动能,将含铁粉剂喷入铁水中,脱除铁水中的部分Si。通过选择合理的系统参数,优化脱硅粉剂配比,调节下料速度在10kg/s以上,并开发了喷吹脱硅自动控制系统,下料量控制精度达到了1%,保证了脱硅反应的平稳进行,脱硅剂反应充分,脱硅量0.07%。     

气泡微细化实验中均混时间的研究

在水模型实验的指导下,依照佐野先生提出的高效的镁精炼铁水计划进行实验.本文采用电导率法测定溶池的均混时间,考察喷镁脱硫钢包内钢液的一些主要工艺和结构参数对均混时间的影响,通过比较均混时间来衡量气泡的微细化程度;通过水模型实验,讨论钢包喷吹镁粉脱硫精炼过程中,不同的搅拌桨结构、搅拌模式、搅拌速度、气体流量、搅拌桨的潜入深度和喷嘴结构等一系列因素对均混时间的影响,分别做了单机械搅拌,单吹气搅拌和机械搅拌加上吹气搅拌的铁水包水模型实验.对实验结果进行对比分析,把上述不同参数条件下的均混时间列出表格,绘出曲线,进行了以铁水包脱硫效率为最终考察目标的铁水包单吹镁脱硫的工艺优化研究,得到最佳的优化参数,并把这些参数运用到实验中,来研究讨论气泡微细化的程度,指导本水模型实验.通过水模型实验,最终确定130t钢包的最佳工艺优化参数.     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.