铜冷却壁冷却恢复技术的传热过程

 铜冷却壁在正常状态时由于良好的导热性,在其热面形成稳定的渣铁壳,起到保护冷却壁的作用。近几年,高炉的铜冷却壁水管损坏时有发生,而当冷却壁水管损坏1或2根时,冷却壁能否继续正常工作值得研究。计算了铜冷却壁在水管完好和部分水管损坏时的温度场分布,发现单根水管损坏使热面温度急剧升高近110℃,加剧冷却壁烧损,需及时恢复冷却壁的冷却能力。通过用金属软管修复破损水管,分析了软管直径、水速、水管填料的导热系数等因素对冷却壁温度场的影响。结果表明,软管在允许条件下应选用较大内径,选取较大导热系数的填料。利用软管修复单个水管后,壁体最高温度下降约90℃,对于损坏少数水管的冷却壁能有效修复。     

基于ANSYS的高炉铸钢冷却壁传热分析

运用大型有限元通用软件ANSYS,对高炉铸钢冷却壁稳态工况进行传热学分析。同时根据计算结果,分析了冷却壁在稳定工作状态下的温度、热流以及温度梯度的分布情况。通过分析可以找出冷却壁工作中需要注意的地方,为今后冷却壁的维护和设计提供参考。还讨论了冷却水管水垢对高炉铸钢冷却壁温度场的影响。结果表明,水垢每增加1mm厚,会使冷却壁热面温度升高约60℃。     

铜冷却壁结构参数的传热分析

对轧制铜冷却壁和铸铜冷却壁以及内铸钢管和monel合金管的铸铜冷却壁的镶砖高度。铜的热导率、砖的热导率、肋高、冷却水管直径和水管间距对热流密度、铜的最高温度、镶砖最高温度和炉壳温度的影响进行了研究比较。     

高炉铸钢冷却壁最佳结构的传热学分析

采用通用有限元软件ANSYS计算了300 m3高炉铸钢冷却壁的温度场和应力场,数值分析铸钢冷却壁冷却水管内径、间距、壁体厚度、镶砖厚度以及冷却水流速对冷却壁热面最高温度和热应力的影响.导出了高炉铸钢冷却壁的初步优化结果:冷却水管间距200 mm,水管内径20 mm,壁体厚度为180 mm,镶砖厚度为70 mm,与之相匹配的冷却水流速为2.0 m/s.     

冷却水管管形变化下的高炉冷却壁传热分析

建立了铸钢冷却壁的三维传热和热应力的数学模型,采用通用有限元软件ANSYS计算了冷却壁的温度场和应力场。计算结果表明：冷却水管由圆管改为椭圆管后,冷却壁热面最高温度和热应力升高不大,为冷却水管由圆形改成椭圆形提供了理论依据,由于椭圆水管截面积减少,就可以减少壁体厚度和大量节约冷却水量,从而达到降低炼铁成本的目的。     

高炉铸钢冷却壁冷却水管的优化研究

针对建立高炉铸钢冷却壁的三维传热和热应力模型,采用通用有限元软件ANSYS计算了高炉铸钢冷却壁的温度场和应力场,通过数值计算分析了高炉铸钢冷却壁冷却水管形状对冷却壁热面最高温度和热应力的影响。计算结果表明：冷却水管改圆管为椭圆管后,冷却壁热面最高温度有所下降。当椭圆管横截面与圆管相同并且长短轴之比为0．6时,最高温度降低了2．8％,热面最大热应力降低了7．5％。而周长不变的椭圆管降温效果并不理想,但长短轴之比为0．4时最大热应力降低了12．8％。综合考虑各因素,把圆管做成面积相同的长短轴之比为0．55～0．65的椭圆管,可以取得比较好的冷却效果。这对于减少冷却水流量,减薄冷却壁体厚度、降低炼铁成本也有重大意义。     

铸钢冷却壁在济钢高炉的应用

济钢一炼铁厂5座高炉先后在炉腹至炉身下部安装了不同数量的铸钢冷却壁,生产实践表明,铸钢冷却壁热面温度比球墨铸铁冷却壁低,在高炉高热负荷区域采用铸钢冷却壁有利于延长高炉炉体寿命。     

基于热态实验的冷却壁传热分析

建立了高炉铸钢冷却壁传热数学模型,并通过热态实验验证数学模型,进而根据所建模型对冷却壁的稳态工况进行仿真计算.同时根据计算结果讨论了冷却水管水垢厚度、气隙层厚度对高炉铸钢冷却壁温度场的影响.结果表明:这两个因素对冷却壁的性能都具有很大的影响,在高炉操作和冷却壁的设计制造中必须重视.     

鞍钢大型高炉炉缸冷却水需求量的计算分析

采用按流体分布状态和所允许最大热流强度的方法,对鞍钢3200m~3高炉炉缸冷却水需求量进行了计算,并就冷却水流速、水管直径和气隙参数对冷却壁热面温度影响进行了分析。认为鞍钢3 200m~3高炉炉缸冷却壁用φ50mm×6mm水管和1250m~3/h的冷却水量,对冷却强度和系统回路阻损的设计都是偏小的。     

高炉用铜-钢复合冷却壁传热及力学性能分析

采用热力耦合方法研究了铜层厚度和冷却水道间距对铜-钢复合冷却壁温度及应力分布的影响.以1∶1比例铜-钢复合冷却壁进行了热态试验,测试了铜-钢复合冷却壁温度分布,计算了热态试验条件下铜-钢复合冷却壁的温度分布,计算结果与试验结果基本吻合.计算结果显示,铜-钢复合冷却壁铜层厚度增加,壁体最高温度和最大等效应力减少,铜层厚度上限值为70mm;冷却水道间距减少可以降低壁体最高温度和最大等效应力,当冷却水道间距小于220mm时,减少冷却水道间距对降低壁体最高温度和最大等效应力作用较小.铜层厚度为60mm,冷却水道间距为220mm的铜-钢复合冷却壁在高炉热负荷较高区域工作不易发生塑性变形损坏.     

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)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

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.