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为了满足高牌号无取向硅钢和高磁感取向硅钢的常化退火工艺要求,设置了常化炉冷却段,通过气雾、空气及喷淋水达到带钢冷却要求。其中气雾冷却段要求最高,故其气雾冷却技术越来越受到关注。目前已投入工业应用的两相流冷却技术主要采用空气雾化水,将雾化后的气体和水滴的混合物直接喷射到带钢表面以较快速率冷却带钢。气雾冷却具有换热系数大、冷却效率高等优点,是一种较为理想的冷却方式。 相似文献
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为了满足高牌号无取向硅钢和高磁感取向硅钢的常化退火工艺要求,设置了常化炉冷却段,通过气雾、空气及喷淋水达到带钢冷却要求。其中气雾冷却段要求最高,故其气雾冷却技术越来越受到关注。目前已投入工业应用的两相流冷却技术主要采用空气雾化水,将雾化后的气体和水滴的混合物直接喷射到带钢表面以较快速率冷却带钢。气雾冷却具有换热系数大、冷却效率高等优点,是一种较为理想的冷却方式。 相似文献
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为了满足高牌号无取向硅钢和高磁感取向硅钢常化退火的工艺要求,设置了常化炉冷却段,通过气雾、空气及喷淋水达到带钢冷却要求。其中气雾冷却段要求最高,故气雾冷却技术越来越受到关注。目前工业上应用的两相流冷却技术主要采用空气雾化水,雾化后的气体和水滴的混合物直接喷射到带钢表面以较快冷却带钢。气雾冷却具有换热系数大、冷却效率高等优点,是一种较为理想的冷却方式。 相似文献
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连续退火炉中保护气氛及结构特性对带钢冷却特性的影响 总被引:1,自引:0,他引:1
采用标准kε-紊流模型,对连续退火炉中快冷段局部带钢的二维非稳态温度场进行CFD模拟,模拟与实际结果吻合较好。研究结果表明:从温度均匀性和冷却速度来看,当氢气体积分数为30%时,冷却效果最佳;控制最优的冷却速度可以通过控制带钢初始温度、带钢与风箱间距和冷却气体喷出速度、冷却介质的含量等参数来实现。 相似文献
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立式连续热处理炉快冷段混合气的氢气含量,对换热系数和带钢温度有很大的影响,体现了冷却气体物理性质与换热系数和带钢温度之间的关系。在其他条件相同而氢气含量不同的条件下,对带钢传热状态进行分析,利用冷却设备几何结构、努塞尔数与换热系数的关系,得到带钢瞬时冷却温度计算公式,为生产及工程设计提供了一定的依据。 相似文献
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为提高热轧换规格首块钢头部卷取温度命中率,采用数据挖掘技术,从历史带钢冷却数据中推断出与实际带钢相匹配的卷取温度模型水冷换热学习系数,并将其应用于模型预设定计算。首先,对冷却特征参数进行识别,按照相对型、绝对型、相等型和策略型四种方式进行定义,并对实际带钢与历史带钢的各项冷却特征参数进行相似距离计算。当历史带钢的总相似距离满足要求时,将其聚类为实际带钢的相似卷,并考虑各相似卷的时间影响,计算相似权重值;随后,基于相似带钢的头部和尾部信息,建立由卷取温度预报误差、偏离学习系数回归值惩罚项和偏离默认值惩罚项等构成的目标函数以及相应的约束条件,采用梯度下降法求解该二次规划问题,通过三次优化逐步计算出学习系数参考值和表征学习系数与带钢速度及目标卷取温度呈双线性关系的两个参数;最后,根据实际带钢的穿带速度、目标卷取温度等冷却条件计算冷却设定所需的学习系数。现场应用表明:基于十万块历史带钢冷却数据驱动的模型参数即时自适应设定算法可增强卷取温度模型对带钢头部冷却的预设定能力,学习系数即时自适应设定能力随着内存中保存的历史带钢冷却数据的多样性和检索出的相似卷数量的增加而提升。 相似文献
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ZHI Ying LIU Xiang-hua WANG Guo-dong 《钢铁研究学报(英文版)》2007,14(3):26-29,55
After water cooling,there is a big temperature difference between the center and the surface of strip,which leads to the heat transfer from the center to the surface,and the surface temperature can rise in a short time.The finite element method was used to simulate the phenomena of re-reddening on the surface of strip and to analyze the temperature field of hot rolled strip during laminar cooling,and the periodical variation curve of the cooling rate was obtained during water cooling and subsequent re-reddening.The results show that the critical line of the cooling rate is at 1/3 of the half-thickness from the strip surface.The regression model of the relation of re-reddening temperature,time,and distance from the surface was obtained in the re-reddening region.Re-reddening regularity on the surface of strip under the condition of different thickness and cooling rate was also studied. 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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建立了热轧带钢层流冷却过程中温度场的三维有限元模型,对3 mm厚带钢轧后冷却过程带钢温度场进行模拟计算,得出卷取温度比现场测量值低9.5 ℃,相对误差为1.42%,验证了模型和假设的合理性。研究了上喷嘴直径对带钢温度的影响,带钢上表面宽度方向上存在2种不同的冷却区域:位于喷嘴正下方层流冷却过程中交替经过冲击区和平流区的区域和位于两喷嘴之间层流冷却过程中只经过平流区的区域,这造成带钢宽度方向上温度分布不均匀。计算结果表明,喷水量保持不变的情况下,存在一个最佳喷嘴直径,使带钢宽度方向上温度分布更均匀。喷水速度保持不变,增加喷嘴的直径有利于带钢宽度上方温度均匀,但增加了喷水量,降低了带钢的卷取温度。 相似文献
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热态上料高炉半净煤气的温度为600~700℃,需将其温度降低至250℃以下,以满足布袋除尘系统对煤气温度的要求。高炉煤气蒸发冷却塔作为干式冷却设备,它通过双流喷嘴将冷却水雾化喷入冷却塔内,利用水的汽化潜热将煤气温度迅速降低,同时也降低了煤气的含尘浓度。介绍了蒸发冷却塔原理及其系统组成,就某个项目做出蒸发冷却塔设计计算,并得出相应结论。 相似文献
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In the current research, the ultra fast cooling (UFC) of a hot stationary AISI‐304 steel plate has been investigated by using air atomized spray at different air and water flow rates. The initial temperature of the plate, before the cooling starts, is kept at 900°C or above. The spray was produced from a full cone internal mixing air atomized spray nozzle at a fixed nozzle to plate distance; and the average spray mass flux was varied from 130 to 370 kg m?2 s by selecting different combinations of air and water flow rates. The surface heat flux and surface temperature calculations have been performed by using INTEMP software and the calculated results have been validated by comparing with the measured thermocouple data. The heat transfer analysis indicates that the cooling occurs in the transition boiling regime up to surface temperature of 500°C and thereafter it changes to nucleate boiling regime. The superposed flow of air on the hot plate enhances the cooling in the temperature range of 900–500°C by sweeping the partially evaporated droplets from the hot surface. However, due to the high percentage of fine water droplets in the resultant spray produced at higher air flow rates, the maximum cooling rate is achieved at the medium air flow rate of 30 N m3 h?1. The cooling rate (182°C s?1) produced by an air atomized spray is found to be in the UFC regime of a 6 mm thick steel plate. The findings of this research can be considered as the basis for the fabrication of cooling system in the run‐out table of a hot strip mill. 相似文献
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根据高强钢生产工艺对冷却速率的要求,分析了在连续退火工艺中,喷气冷却对带钢冷却速率的影响,并提出了相应的措施提高带钢冷却速率,达到了喷气冷却生产高强钢的目的。 相似文献
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Modern steel grades require accurate temperature control during processing. The cooling section technology has to deliver prescribed cooling rates while fulfilling specific constraints, e.g. on the minimum surface temperature. For all material thicknesses, numerical cooling system set value prediction is advantageous and above 10 mm, the possible cooling rates and the experimental parameter determination are limited by physical constraints. Laboratory measurements provide quantitative experimental data on the heat transfer coefficient (HTC) depending on the cooling system parameter water impact density and the temperature difference. The desired final material properties determine temperature control and cooling rate. This information is used to predict the optimum cooling section set values for a specific cooling task. The inverse modelling calculations use a simple cooling section process model. Illustrative examples for optimum cooling of strip or sheet material using water spray cooling demonstrate the approach. Additionally, the physical limitations due to the finite heat conductivity of the strip are calculated and discussed. 相似文献
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济钢冷轧板厂热镀锌生产线冷却塔的主要功能是采用风冷及水冷方式,冷却从锌锅出来的钢带。但在最近的生产中,冷却塔带钢严重跑偏。为此,对纠偏原理进行了深入研究,并对影响冷却塔跑偏的因素进行系统分析,并采取了调整措施,取得良好效果。 相似文献