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本文介绍了一种新型的采用喷雾冷却方法的连铸结晶器,以其快速而均匀的传热,使钢液获得较普通冷却方法的结晶器更快的凝固速度,形成较厚的坯壳,改善铸坯质量。本文将介绍喷雾冷却结晶器在方坯、板坯和型坯连铸中的应用。 相似文献
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本文阐述了连续铸钢气水喷嘴的结构型式及其在设计中的主要技术要求。从理论上分析了雾化介质的压力与被雾化的水的粒径关系;提出了设计气水喷嘴时。选择压缩空气与水的合理压力范围.在导出气水喷雾冷却条件下传热数学模型的基础上对传热问题进行了初步探讨,并对气水喷雾冷却节水的原因进行了简要分析。 相似文献
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针对喷雾冷却传热技术在连铸二冷段中的应用情况,对目前连铸二冷中的两种主要冷却方式即空气辅助雾化和压力雾化进行了实验研究和探讨。通过实验得出了压力雾化和空气辅助雾化的一些规律及特性。 相似文献
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小模块冷却壁是将性能优异的耐火材料直接浇铸在平行排列的冷却水管上而形成的一种新型冷却设备。采用ANSYS软件建立了小模块冷却壁温度场计算模型,利用该模型计算了炉气温度为1200~1600℃、冷却水流速为0.5~2.5m/s条件下壁体材质导热系数、水管材质、水管直径、水管间距、冷却水流速及工作环境温度等条件变化时小模块冷却壁的温度分布状况。结果表明,小模块冷却壁对炉气温度变化的适应能力较强,壁体材质导热系数、水管间距、壁体厚度对小模块冷却壁传热性能影响较大,而水管直径、水管材质及水流速的影响较小。 相似文献
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针对目前冶金行业转底炉工艺中圆筒冷却机无法回收球团显热的问题,本文提出采用在循环流化床锅炉中广泛应用的滚筒冷却机来冷却球团的新方案,并据此建立滚筒冷却机的传热模型,通过计算得到球团终温与冷却水出口温度及冷却机的表观传热系数。结果表明:球团的终温随滚筒转速的升高而降低,随球团流量和冷却水入口温度的升高而升高;冷却水出口温度随金属化球团流量和冷却水入口温度的增大而增大;冷却机的表观传热系数随滚筒转速、球团流量和冷却水入口温度的增大而增大,随冷却水流量的增大而减小。本文引入滚筒冷却机将球团的温度从1 100℃降低至70℃,同时避免球团内部的氧化问题,符合高温球团的冷却要求,证明了将滚筒冷却机用于转底炉工艺的可行性。 相似文献
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The influence of running water on spray water cooling is experimentally looked at with the aid of a stationary working experimental plant. The running water was fed separately to the sample from above as a defined water film by using a slot nozzle. In addition to the spray nozzle pre-pressure, the velocity of the running water at the slot nozzle exit and the temperature of the running water, the angle of inclination of the sample plane was also varied. By employing three different full cone spray nozzles and setting different nozzle distances, a range of 450 to 2000 l/(m2·min) of the water impingement density was covered. To estimate the marginal influences, samples of 20 × 20 mm as well as 30 × 30 mm were used. Studies of initially pure spray water cooling without the additional running water film revealed a dependency of the heat transfer on the spray water impingement density, the spray water velocity and also the angle of inclination of the sample plane. For nozzles with a low water impingement density, a superimposing of a running water film on the spray water revealed a sharp increase in the heat transfer coefficients compared to pure spray water cooling. For nozzles with a high water impingement density and, therefore, with a high heat transfer already even for pure spray water cooling, the increase of the heat transfer coefficient is minor. 相似文献
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研究了不同喷淋距离下连铸小方坯二冷喷嘴的水量分布,建立了凝固传热模型分析了82B钢连铸坯的热行为。该模型特别考虑了二冷区铸坯表面宽度方向的水流密度分布,并根据铸坯表面测温结果进行了模型校正。采用凝固传热模型研究了喷嘴喷淋距离对连铸二冷均匀性的影响。结果表明:喷嘴喷淋距离的增加有助于提高二冷水横向分布的均匀性,导致铸坯表面温度横向均匀性降低、纵向均匀性提高。这些效果有助于改善铸坯内部裂纹,但是会对角部裂纹产生不利影响。在二冷区前段喷嘴采用低喷淋距离,二冷区末段采用高喷淋距离,既可以提高铸坯角部温度,又能降低表面最大回温速率,有助于同时改善连铸坯角部和内部裂纹。在此基础上,提出了一种连铸小方坯二冷喷嘴布置方式,即二冷区每段喷嘴喷淋距离沿拉坯方向逐渐增加,该方法有助于提高连铸坯“纵?横”冷却均匀性。 相似文献
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在板坯连铸过程中,二冷区传热的均匀性对铸坯表面与内部质量均有重要的影响。首先对国内某钢厂二冷各区的喷嘴进行了喷淋性能测试,根据各冷却区喷嘴的布局及2 000 mm×250 mm断面包晶桥梁钢板坯连铸生产过程的各区水量分布,建立了铸坯三维凝固传热有限元计算模型,模拟分析了铸坯在二冷区内的动态凝固传热行为。在此基础上,优化调整了连铸二冷高温区的喷嘴布局。结果表明,某钢厂原二冷区喷嘴布局条件下,其高温区的铸坯表面温度沿其横向波动较大。典型生产工艺下,二冷4区出口处的铸坯宽面表面横向温差最大,即距角部313 mm处的宽面表面温度最高为1 073 ℃,而距角部873 mm处的宽面表面温度最低为996 ℃,温差达77 ℃。而当铸坯进入二冷弧形区时,铸坯表面的横向温度分布逐渐趋于均匀。将二冷2区的喷嘴安装高度由距铸坯表面170提升至200 mm、3区和4区的喷嘴安装高度由距铸坯表面200提升至240 mm,可使铸坯在高温区内的表面横向温差最大值降至30 ℃以下,大幅改善铸坯表面温度分布的均匀性。 相似文献
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LIUZheng-dong IVSamarasekera 《钢铁研究学报(英文版)》2004,11(3):15-23
The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip. The heat of a hot steel strip is mainly extracted by cooling water during runout. In order to study the heat transfer by water jet impingement boiling during runout, a pilot facility was constructed at the University of British Columbia. On this pilotfacility, the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters, such as cooling water temperature, water jet impingement velocity, initial strip temperature, water flow rate, water nozzle diameter and array of water nozzles, on the heat transfer of heated strip. The results obtained contribute to the optimization of cooling water during runout. 相似文献
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喷淋结晶器是一种新型结晶器,它是用特殊的喷嘴将水喷淋到结晶器的铜板表面上进行铸坯冷却的,这种冷却方式具有较高的传热速度,便于调节结晶器的热流密度,可以提高拉坯速度和铸坯质量,喷淋结晶器的传热现象是很复杂的,本文通过建立传热实验台,对喷淋冷却过程进行较细致的实验研究,找出喷水量和换热系数的关系等,为设计喷淋冷却结晶器提供必要的参数。 相似文献
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《钢铁冶炼》2013,40(8):598-604
AbstractThe aim of the paper is to design the new wide plate mill. The work on the new cooling technology was supported by extensive laboratory testing while a simulator with full scale testing of cooling units was used. The principal objective of the investigation was to establish the design specification of equipment for accelerated cooling, particularly with respect to the product dimensions and steel grades. The possibilities of accelerated cooling are limited by technical parameters of cooling equipment such as thickness of water layer, flowrate, spray height, position of cooled surface to the nozzles and water or plate speed. These parameters were studied for different product temperatures and water impingement densities from 50 to 110 l s?1 m?2. The heat transfer coefficient was determined and compared for each case. There were three recognised significant cooling regions: water layer region, impinging jet region without water layer and impinging region with water layer, which must be taken into account. The application of the new cooling technology showed better flatness product and productivity higher than previous accelerated cooling system, even shorter cooling length. The rejection ratio by flatness problem of new mill was nearly half of the previous one. 相似文献