基于解析法CFD−DEM的烧结矿立式固定床气固接触特性  

Study of gas–solid contact characteristics in a vertical sinter fixed bed using a resolved CFD–DEM method

作　　者：张宇 李承志 郭嘉敏 张伟[2,3] ZHANG Yu;LI Chengzhi;GUO Jiamin;ZHANG Wei(Faulty of Materials,Wuhan University of Science and Technology,Wuhan 430081,China;The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学材料学部,武汉430081 [2]武汉科技大学省部共建耐火材料与冶金国家重点实验室,武汉430081 [3]武汉科技大学钢铁冶金与资源利用省部共建教育部重点实验室,武汉430081

出　　处：《工程科学学报》2024年第10期1753-1763,共11页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(52104340);湖北省重点研发计划项目(2022BCA058)。

摘　　要：烧结矿与冷却气体充分接触是实现烧结矿立式冷却工艺的关键.采用解析计算流体力学−离散元法(CFD−DEM)方法对烧结矿立式固定床的气固接触特性进行了研究,主要模拟了非规则烧结矿在固定床内的堆积过程,并采用浸没边界法和动态网格细化技术获得颗粒表面的流场信息.结果表明,双粒径均匀混合料床的平均空隙率主要取决于小粒径颗粒,大粒径颗粒主要影响料床的大空隙结构及分布.“A型”偏析(中心区域堆积小粒径颗粒,近壁面区域堆积大粒径颗粒)料床压降显著低于均匀混合料床,但颗粒与气体接触不充分;“B型”偏析(偏析方式与“A型”相反)料床兼顾了低压降和气固充分接触的特点.料床实验压降与模拟压降随气体表观流速的变化趋势保持一致,验证了解析CFD−DEM方法的准确性.Ensuring full contact between hot sinters and cooling gas is the key premise for the widespread application of vertical sinter cooling technology at an industrial scale.In this study,the gas–solid contact characteristics in a vertical sinter fixed bed were numerically investigated through a resolved CFD–DEM(computational fluid dynamics–discrete element method)method.The irregular sinter geometries were represented through the multi-sphere clumped method.The sinter packing in a vertical fixed bed was simulated via DEM modeling,and the immersed boundary method and dynamic mesh refining were employed in the CFD–DEM coupling to obtain a high-resolution fluid flow field around the sintered particles.The results showed that the average voidage of the dual-particle-size uniformly mixed bed generally decreased with the decrease in the average sinter particle size.The average bed voidage was mainly determined by the finer sinters,while the larger sinters mainly affected the large voidage structure and its distribution formed in the bed.Compared with the uniformly mixed bed,the segregated mixed bed exhibited a larger average voidage,and the voidage distribution also changed considerably.The fluid flow behavior in the mixed bed was largely influenced by the average bed voidage and the voidage distribution.As the average particle size decreased,the fluid flow in the bed became more uniformly distributed.Under different segregated packing situations,the bed voidage structures in the central zone and near-wall zone differed remarkably,with the fluid flow exhibiting a higher tendency to develop in the zone with larger voidage.The bed pressure drop generally increased with the decrease in the average sinter particle size.Among the uniformly and segregated mixed beds,the bed with“A-type”size segregation(i.e.,finer sinters packed in the central zone while the larger sinters packed in the near-wall zone)showed the lowest overall pressure drop,but the particles inside the bed did not fully contact with the fluid.The bed

关 键 词：计算流体力学−离散元法 耦合计算 浸没边界法 网格细化 烧结矿立式冷却 气固接触 

分 类 号：TF046[冶金工程—冶金物理化学]