内旋流流化床床内颗粒运动特性的试验研究  

EXPERIMENTAL STUDY ON PARTICLE MOTION CHARACTERISTIC IN THE INTERNAL CIRCULATING FLUIDIZED BED

作　　者：徐旭[1] 池涌[1] 李斌[1] 严建华[1] 岑可法[1] 

机构地区：[1]浙江大学热能工程研究所,浙江杭州310027

出　　处：《中国电机工程学报》2001年第11期9-13,共5页Proceedings of the CSEE

基　　金：国家重点自然科学基金资助项目 ( 5 98362 10 )~~

摘　　要：流化床床内颗粒的大规模循环不仅可以加剧了颗粒横向扩散 ,提高燃烬速率 ,实现燃烧的均匀性和稳定性 ,还将有利于促使不燃物质的定向移动排出炉外。文中采用冷态流化床装置 ,应用分层取样技术对微倾斜布风板实现流化床内不均匀布风 ,床内物料混合与分层特性进行了系统的试验。研究床内颗粒扩散的动态特性和流化风速、颗粒密度以及颗粒粒度等因素对流化床内分层的影响 ,并通过求解扩散方程来分析布风不均匀性和布风倾角对风板附近物料扩散的影响。研究表明 :增大流化风速和布风板倾角能够强化颗粒的横向扩散和流化床的内旋流强度 ;对大而重的颗粒存在一个最佳速度比 ,既能实现床内旋流又能防止颗粒的严重分层 ,并针对低风速区的分层现象 ,提出了一个关联式 ,该式的计算值与实验值吻合较好。The fluidized bed incinerator is introduced to deal with municipal sol id waste(MSW) gradually. Large-scale circulation of particle motion in the inte r nal circulating fluidized bed is propitious to accelerate landscape oriental str eam of bed materials, increase fuel combustion efficiency, and to realize unifor mity and stability of MSW combustion. In the paper, a slant air distributor is a pplied to obtain an uneven air distribution in the cold fluidized bed so as to o btain a large-scale circulation of particle motion. The dynamic characteristic o f bed material diffusion is systemic studied. Furthermore, the effect of angel o f air distributor and air distribution on bed material diffusion is analyzed mat hematically. It is evident that: increasing the air velocity and air distributor slant can strengthen the transverse diffusion of particle and the intensity of internal flow in the fluidized bed. For the large and heavy particle, an optimal ratio of air velocity is brought forward to obtain circulation in the fluidized bed and to prevent the high delamination of particles. The tests show that segr egation in the low air velocity zone likely occurs when the air distribution is unfit.For the phenomena of segregation in low air zone, a fomulae concerning wi th the trace particle diameter, density and air distribution ratio is regressed. There is less different between predicted value and experimental one. The resul ts of experiments will be in favor of the design and operation of MSW fluidized bed.

关 键 词：颗粒运动 内旋流流化床 倾斜布风板 试验 

分 类 号：TK229.66[动力工程及工程热物理—动力机械及工程]