填充床内颗粒物料流动的实验和数学模型研究

发布时间：2018-01-06 05:38

本文关键词：填充床内颗粒物料流动的实验和数学模型研究　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：颗粒流动是材料制备工艺中比较普遍的现象,如稀土氧化物制备、钢铁材料制备的高炉、竖炉工艺等。竖炉内颗粒物料的流动现象与竖炉的操作性能、生产效率和产品质量密切相关,掌握填充床中物料的流动规律对认识反应器的特性、进行反应器操作和控制非常重要。研究室温装置内颗粒物料流动规律是认识高温竖炉内颗粒物料流动现象的基础。本文针对准二维室温填充床内颗粒物料流动现象进行实验和数学模型研究。以位于不同停留时间等值线上的示踪颗粒分别标绘出中心和偏心卸料填充床内稳态物料流场(包括缓慢流动区和流动区),并研究了卸料速度对它的影响。以合适的物料流动表观驱动力、物料流动阻力等的表达式为基础,根据质量守恒、动量守恒原理建立了可以描述颗粒物料稳态流动的数学模型。利用SIMPLE算法进行模型方程的离散求解。并利用实验结果验证了所建模型及其数值结果的可靠性。实验和数学模型研究的主要结果为:①填充床内存在明显的物料流动区和缓慢流动区,任一水平高度上物料流动速度沿横向分布不均匀。中心卸料时,物料流动沿经漏口的垂线占优分布;偏心卸料时,在靠近壁面处形成物料流动的边界层现象。卸料流量变化对流动区无明显影响。②体积力方向的表观驱动力的表达式反映了物料流场与体积力场的较强方位对应关系和填充床内流动区和死料区共存的现象;物料流动阻力的表达式说明物料表观速度越大,物料流通性越好,通过惯性维持物料流动状态的作用变强。③论文建立的连续介质模型,能预测物料流动区、缓慢流动区和壁面附近的物料流动边界层现象;实验结果与模型计算结果吻合得较好。所建模型为动力学模型,与其他模型相比有较好的进一步发展的空间,为下一步研究填充床内气固两相耦合、障碍物绕流现象、非稳态卸料等奠定了基础。本文研究工作对了解颗粒物流流动规律提供了一种比较简单的数学模拟方法。为未来进一步研究竖炉、高炉等炼铁工艺的模拟和优化等提供了一种可能的手段。
[Abstract]:Particle flow is a common phenomenon in material preparation process, such as rare earth oxide preparation, iron and steel material preparation of blast furnace, shaft furnace process, and so on. The production efficiency is closely related to the quality of the product. It is important to understand the characteristics of the reactor by mastering the flow law of the material in the packed bed. It is very important to operate and control the reactor. It is the basis of understanding the particle material flow phenomenon in the high temperature shaft furnace to study the particle material flow law in the room temperature plant. This paper aims at the particle material flow in the quasi-two-dimensional room temperature packed bed. The steady state material flow field in the packed bed was plotted with the tracer particles located on the isoline of different residence time, respectively, and the steady state material flow field in the packed bed with eccentric discharge was plotted by using the image as an experimental and mathematical model. Including slow flow zones and flow zones). The influence of unloading speed on it is also studied. Based on the expression of material flow apparent driving force and material flow resistance, the mass conservation is carried out. The momentum conservation principle is used to establish a mathematical model which can describe the steady state flow of granular materials. The discrete solution of the model equation is carried out by using SIMPLE algorithm, and the experimental results are used to verify the model and its numerical results. Reliability. The main results of experimental and mathematical model studies are as follows:. 1 there are obvious material flow areas and slow flow areas in the packed bed. At any horizontal height, the velocity of material flow along the transverse distribution is uneven. When the material is discharged from the center, the material flow dominates along the vertical line through the leak. Eccentric discharge. The boundary layer phenomenon of material flow is formed near the wall. The expression of apparent driving force which has no obvious influence on the flow region by the change of discharge flow rate reflects the strong azimuth correspondence between the material flow field and the volume force field. Relationship and coexistence of flow zone and dead zone in packed bed; The expression of material flow resistance shows that the larger the apparent velocity of the material, the better the material circulation. The continuum model established in this paper can predict the material flow area through the inertial maintenance of the material flow state. 3. The material flow boundary layer phenomenon in the slow flow region and near the wall; The experimental results are in good agreement with the calculated results. The model is a dynamic model, compared with other models, there is a better room for further development, for the next step to study gas-solid coupling in the packed bed. The research work in this paper provides a simple mathematical simulation method for understanding the flow law of particle logistics and provides a simple mathematical simulation method for the further study of shaft furnace in the future. The simulation and optimization of ironmaking process such as blast furnace provide a possible means.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TF51

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