直通式辊底加热炉传热数学模型研究

通过分析CSP工艺中直通式辊底加热炉的热工及结构特性,采用区域法建立各区域的辐射能量平衡方程,并与加热炉内连铸坯的二维瞬态导热模型相耦合,建立长一维直通式辊底加热炉炉内传热数学模型.通过对数学模型的求解,研究分析了加热炉内炉气、板坯温度分布的变化规律.     

CSP辊底加热炉供煤气量随坯厚、坯温变化规律的模拟研究

研究了CSP辊底加热炉内的传热过程及其规律.采用数值模拟的方法,在进行合理简化后,建立总能量平衡基础上的炉内热过程数学模型,其中辐射传递方程的求解采用离散坐标法.自主开发了该炉型的通用热过程模拟软件,采集包钢CSP薄板坯连铸连轧厂的生产数据进行验证计算,计算所得钢坯温度与实际温度的相对误差小于1%,表明该模型假设合理,建模正确;该软件能够应用于该类型加热炉的设计、管理和研究等领域,为确定CSP生产线高拉速(提高入炉坯温)、多钢种的生产工艺参数创造了条件.     

辊底式高温固溶炉在线数学模型的开发及应用

为精确跟踪某公司新建辊底式高温固溶炉内钢板温度,详细研究了明火炉内炉气温度、钢板内部导热和炉内传热机制,建立了考虑炉段间耦合的炉气温度数学模型和钢板温度跟踪模型,采用FDM法对数学模型离散化,结合TDMA数值方法进行求解.在线应用结果表明所建立的数学模型简单、可靠,为钢板加热质量的控制提供了科学依据,提高了出炉温度命中...     

CSP辊底式加热炉温度控制分析

分析了CSP辊底式加热炉温度控制的特点,指出影响坯料温度的因素、温度变化状况;对影响板坯加热的主要技术因素进行了初步研究,并介绍了该炉型板坯温度的控制方法与经验。     

热轧板坯加热工艺优化

建立了三段步进梁式加热炉板坯加热过程数学模型,用全隐式有限差分法对数学模型进行离散化,开发了板坯温度场计算模型.采用该模型重点研究了板坯宽度对板坯中心温度变化过程的影响规律.研究结果表明,对于厚度为200 mm的板坯,当板坯宽度大于600 mm时,板坯中心温度变化过程与板坯宽度无关.以此为根据,优化了板坯加热工艺,达到了提高生产效率并节能减排的目的.     

步进式加热炉内热工过程的数值模拟

建立步进式加热炉内流动、燃烧和传热的数学模型。炉内流场的模拟采用k-ε双方程模型,辐射换热计算采用P-1辐射模型,气相燃烧采用Species Transport模型,流场计算采用Simpler算法。采用上述模型与算法得到了炉内详细合理的温度、速度和浓度分布,并对其中影响板坯加热的温度场进行了实验验证。     

辊底式热处理炉数学模型

以某中厚板厂辐射管加热辊底式热处理炉为研究对象,实现了炉内热过程的模型化.该模型主要包括炉内物料跟踪模块、钢板温度场模块、炉围温度场模块等.采用假想面法求得了辐射管炉炉膛热交换二维化的角系数,并作了三维修正.在辊底炉连续运行制度和摆动运行制度下,研究了钢板物料跟踪和温度跟踪的不同特点,提出了改进型1/n摆动方案及相应的物料跟踪函数关系.     

热轧板坯加热温度场数值模拟及应用

 建立了三段步进梁式加热炉板坯加热过程数学模型,用全隐式有限差分法对数学模型进行离散化,开发了板坯温度场计算模型。采用该模型重点研究了板坯宽度对板坯中心温度变化过程的影响规律。研究结果表明,对于厚度为200 mm的板坯,当板坯宽度大于600 mm时,板坯中心温度变化过程与板坯宽度无关。以此为根据,优化了板坯加热工艺,达到了提高生产效率并节能减排的目的。     

中板厂加热炉数学模型数值模拟

以某中板厂加热炉为研究对象,建立四段步进梁式加热炉板坯数学模型并采用有限容积法进行了离散,模拟了钢坯内部温度场,与黑匣子试验数据进行比较,证明模型建立准确可靠.研究了板坯不同入炉温度以及不同厚度对加热时间的影响规律,并得出加热时间与入炉温度和厚度之间的经验公式.     

CFD仿真技术在板坯加热炉的应用

以某公司热轧厂常规与双蓄热烧嘴组合供热的板坯加热炉为研究对象,建立该加热炉炉内流动、传热和燃烧过程三维物理数学模型,并运用CFD仿真技术对其进行数值计算,得出炉内速度场和温度场的分布规律。同时,研究了板坯和烟气之间传热特性。     

The Influence of Oxide Scale on Heat Transfer during Reheating of Steel

The present work presents methodology and development of a mathematical model for prediction of the influence of oxide scale on heat transfer during reheating of steel in an industrial furnace. In this developed model, temperatures inside the steel billet were measured and with thermocouples at selected places and were collected by a water cooled computer that was traveling inside the slab. CFD is used to calculate the flow field inside of a furnace. The mass‐transfer coefficient of the scale formation is obtained by solving the convection mass‐diffusion equation across a boundary layer to the surface of a flat plate. A model for inverse heat conduction is employed to calculate the local surface temperature and heat flux on top of the growing oxide scale layer on a slab moving through a walking beam reheating furnace. By using the inverse method, the transient temperature and heat flux was firstly determined on the surface of the steel. During subsequent computations, the growth of the scale was calculated and the surface temperature of the oxide scale was extracted by using the Cauchy data from the previous calculations. The sensibility of the model on steel physical parameters is studied, and suitable parameters were obtained for heating a low carbon steel plate in the reheating furnace. Results show that the oxide scale layer should not be neglected in reheating models.     

Computer Simulation of the Slab Reheating Furnace

Abstract

The development of a mathematical model for predicting steady-state heat transfer within the push-type slab reheating furnace is described and preliminary model predictions presented. Radiative exchange within the furnace chambers is calculated using the zone method, while the thermal response of the slabs moving through the furnace is obtained using a finite difference approximation for transient two-dimensional conduction, neglecting axial effects. The model accounts for the presence of the skidrail structure and the furnace sidewalls, but in its current form requires knowledge of the temperature distribution within the furnace gas. In addition to longitudinal temperature and heat-flux profiles, contour plots of slab temperature in the transverse plane of the furnace are presented. At any longitudinal distance into the furnace, heat flux to the slab surface is shown to vary significantly across the slab, even for the case of uniform transverse gas temperature. In agreement with other studies, the primary cause of skidmark formation is found to be radiative shielding of the slab surface by the skidrail structure. The model indicates that skidmark severity can be expected to increase with furnace throughput, but this situation could be alleviated by reducing the size of the skidrail structure. The effectiveness of reflective coatings applied to the skidrail surfaces, in reducing skidmark effects, is found to depend upon the temperature of the surfaces relative to the local slab surface temperature.     

辐射管辊底式热处理炉数学模型的研究与应用

采用假想面法建立了辐射管辊底式热处理炉炉内钢板加热的二维数学模型,开发了辐射管热处理炉模型控制系统。该模型包括钢板温度跟踪和炉温设定两个模块,钢板温度跟踪可以实时计算钢板在炉内的温度,为钢板热处理进入保温状态提供依据;炉温设定可以计算不同钢种、不同厚度、不同热处理目标温度下钢板对应的炉温设定值范围,用于指导生产。该模型已成功应用于某公司的辐射管辊底式热处理炉上,通过埋偶试验对模型进行了验证。试验结果表明,模型计算精度在±5℃以内,控制效果良好。     

热轧步进式加热炉内钢坯温度场数值模拟

有用有限差分法，建立了热轧步进式加热炉内钢坯三维温度场的数值计算模型，结合攀钢热轧厂热炉的实际生产条件，对钢坯加热过程的温度场进行了数值模拟。通过现场拖偶实验准确确定了钢坯加热的边界条件，并验证了模型计算结果的准确性，在此基础上，通过模拟计算研究了加热工艺，待轧保温制造对钢坯温度场的影响，为优化轧制加热工艺提供科学依据。     

Estimation of the Transient Surface Temperature,Heat Flux and Effective Heat Transfer Coefficient of a Slab in an Industrial Reheating Furnace by using an Inverse Method

In the steel industry it is of great importance to be able to control the surface temperature and heating or cooling rates during heat treatment processes. In this paper, a steel slab is heated up to 1300°C in an industrial reheating furnace and the temperature data are recorded during the reheating process. The transient local surface temperature, heat flux and effective heat transfer coefficient of the steel slab ares calculated using a model for inverse heat conduction. The calculated surface temperatures are compared with the temperatures achieved by using a model of the heating process with the help of the software STEELTEMP® 2D. The results obtained show very good agreement and suggest that the inverse method can be applied to similar high temperature applications with very good accuracy.     

基于CCD的高炉风口回旋区三维温度场的检测技术

在存在多介质的高炉回旋区内,首先利用安装在风口直吹管窥视孔的电荷耦合器件(charged couple device,CCD)摄像机可以获得高炉回旋区内累积的二维温度辐射图像,然后将高炉回旋区均分成若干小块,利用数学模型近似模拟回旋区内的辐射传热过程并建立矩阵方程,通过求解方程获得高炉回旋区内的三维温度场.在模拟辐射传热过程中,本文提出了一种更有效也更符合实际生产的新方法——基于距离的高斯函数模型来模拟高炉内介质的辐射能量传播过程并获得了较好的三维温度场.由于存在波动误差以及电荷耦合器件摄像机测量误差等,所以我们通过在测量数据中添加随机误差来验证重构温度场的有效性以及稳定性.结果显示重构的三维温度场与真实温度场非常接近,误差在高炉工业允许的5%范围以内.      

辊底式连续热处理炉数模优化控制仿真系统

以某公司辊底式连续热处理炉为研究对象，在详细分析其传热机理的基础上，建立了钢坯在炉内加热过程数学模型，针对炉型紧凑，加热中厚板，有最小极限辊速限制等特点，开发了基于加热过程数学模型及连续、摆动运行加热控制策略的仿真系统。验证表明，该系统能有效地模拟钢板在炉内加热升温的全过程。可以对炉辊速度和炉区温度进行寻优计算，为在线控制提供辊速及炉温制度最佳数据。     

炉内板坯表面温度实时监测技术及温升过程数值研究

采用自主研发的比色高温监测系统,实时检测板坯表面温度,依据热传导理论建立了加热炉钢坯加热过程的数学模型,采用有限元法对数学模型进行了离散化分析,开发了钢坯内部中心温度随表面加热过程变化的数值模型。根据检测的钢坯表面温度及开发的数值模型实时通过有限元法[1]估算钢坯中心温度,与传统的通过热电偶探测相比精确了0.46%~0.53%[2];同时根据检测的钢坯表面与中心温差对实时建立温度补偿模型起到辅助作用,同时可以将温度补偿数据实时传递给燃烧优化控制系统,从而建立了基于钢坯表面温差补偿模型的燃烧优化控制,优化调整燃烧工艺,保证了钢坯加热质量,实现了节能降耗和效益提升。