天然气不换向蓄热式熔铝炉的模拟应用

叙述了蓄热式燃烧技术的工作原理,并对燃料换向蓄热式燃烧技术和燃料不换向蓄热式燃烧技术进行了比较。利用 CFD 软件 FLUENT,采用标准k-ε湍流模型、漩涡破碎模型,对20 t熔铝炉炉内传热及烟气流动进行了数值模拟,得到了炉内气体温度场、流场的分布情况,为不换向蓄热式熔铝炉的应用提供了理论基础。改造后,实际的节能效果验证了模拟的正确性。     

50t对冲式不换向蓄热式天然气熔铝炉的数值模拟

简述了蓄热式燃烧技术的工作原理,并对燃料换向蓄热式燃烧技术和燃料不换向蓄热式燃烧技术进行了比较。针对目前大型的50 t以天然气为燃料的圆形熔铝炉,利用CFD软件,对采用对冲式不换向熔铝炉炉内传热、流动以及燃烧进行了三维稳态流动的模拟研究。通过数值模拟得到了炉内气体温度场、流场的分布情况,为对冲式不换向蓄热式熔铝炉的设计与研究提供了理论基础。最后,通过实际工程项目的节能效果验证了数学模型及数值模拟的正确性。     

北岛高效蓄热式工业炉的开发与应用

介绍了高效蓄热式工业炉 (北岛炉 )的技术特点及其在工业生产上的应用效果。北岛炉将蓄热式热回收和换向式燃烧系统与炉体结合于一体 ,可将空气和煤气同时预热到 110 0℃ ,系统排烟温度低于 15 0℃。在轧钢加热炉上应用 ,可以以全高炉煤气为燃料。实际应用结果表明 :节能达 30 %～ 5 0 % ,并提高炉内温度均匀性 ,减少氧化烧损 ,取得了显著的节能效益和环境效益。     

对蓄热炉问题的分析和思考

对蓄热炉的问题进行分析,得出几点结论:蓄热炉存在燃烧换向、温度交变、影响加热质量、综合经济效益差等问题;理论和实践表明:燃烧换向是蓄热炉问题的根源;蓄热炉不适合钢铁联合企业的轧钢工序。     

空气单蓄热式烧嘴燃烧过程的数值模拟及其参数优化

文章建立了空气单蓄热式烧嘴的物理数学模型,采用FLUENT软件对蓄热式烧嘴的燃烧过程进行了三维数值模拟.研究表明,煤气和空气约在炉宽方向6～7m处燃烧完全,炉宽方向3～7m的区域为高温段,温度最高峰值约在5m处;炉内平均温度随煤气负荷和二次空气预热温度的增加而增加,随一次风比例的增加而降低;煤气负荷和二次空气预热温度对炉内温度场分布的影响最为显著,空气系数次之,而一次空气量的影响较小.     

不换向蓄热式燃烧技术在环形熔铝炉上的应用

叙述了蓄热式燃烧技术的起源、发展和工作原理,对燃料换向蓄热式燃烧技术和燃料不换向蓄热式燃烧技术进行了比较,燃料不换向蓄热式燃烧在环形熔铝炉上应用后,年节煤气创效351万元.     

北京朗天环宇节能科技有限公司

北京朗天环宇节能科技有限公司是从事节能、环保的专业化公司，现主要从事蓄热式高温空气燃烧技术的研究，开发和工程实施。公司拥有连续，稳定火焰（燃料不换向）蓄热式高温空气燃烧技术的全部自主知识产权，其中包括发明专利一项《蓄热式高温空气燃烧装置及其方法》，     

中板加热炉蜂窝蓄热体热工特性研究

以中板174m^2蓄热式空煤气双预热连续加热炉为原型，建立了高效陶瓷蓄热体的三维非稳态流动及传热数学模型，采用数值分析的方法对蓄热体在不同换向周期条件下的热工特性进行了研究。结果表明，随着换向周期的延长，蓄热体出口烟气的平均温度逐渐升高，空气和煤气的出口平均温度逐渐降低；在相同的换向周期下，空气换热器蓄热体内的最高温度比煤气换热器蓄热体内的最高温度高，过长的换向周期也会引起蓄热体内较大的温度波动；换向周期对平均余热利用效率和平均温度效率都有较大的影响，其最佳换向周期应定在60s左右。     

换向时间对加热炉蓄热室内温度分布的影响

采用高温空气燃烧技术的蓄热式加热炉在钢铁企业应用广泛。蓄热室是蓄热式加热炉的重要组成部件，换向时间是加热炉蓄热室的重要操作参数。为了探讨换向时间对蓄热室内温度分布的影响，以鞍钢连轧作业区1号加热炉为原型，搭建了加热炉蓄热室的试验装置。填充了10层蜂窝陶瓷蓄热体，开展了换向时间对蓄热室温度变化规律、沿蓄热室长度方向温度梯度变化规律影响的试验研究，分析了换向时间对蓄热室传热性能的影响。研究表明，蓄热室的温度随换向时间的延长呈现周期性变化。随换向时间延长，蓄热室平均温度呈现出先降低后升高的趋势，沿蓄热室长度方向的平均温度梯度先增大后减小。试验用加热炉的最佳换向时间为70 s，对应的热回收率、温度效率和综合传热系数分别为81.6%、91.4%和18.3 W/(m2·℃)。     

换向与不换向蓄热式燃烧技术的优劣比较

叙述了蓄热式燃烧技术的工作原理,并对燃料换向蓄热式燃烧技术和燃料不换向蓄热式燃烧技术进行了比较,发现换向蓄热式燃烧技术熔化速度快,造价高,适用于10t以上的熔铝炉;不换向蓄热式燃烧技术熔化速度慢,故障率低,适用于10t以下,特别是燃重油的小型熔铝炉。     

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.