湿颗粒流化床流动特性的实验研究  

Experimental Study on the Hydrodynamic Characteristics of the Fluidized Bed With Wet Particles

作　　者：徐惠斌[1,2] 钟文琪[1,2] Aibing Yu 袁竹林[1,2] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,能源与环境学院,南京210096 [2]东南大学-蒙纳士大学联合研究院,颗粒系统仿真联合研究中心,苏州215123 [3]澳大利亚蒙纳士大学化学工程系,墨尔本VIC3800

出　　处：《工程热物理学报》2017年第6期1257-1262,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金重大项目(No.51390492);国家自然科学基金(No.51576046);国家杰出青年科学基金(No.51325601)

摘　　要：基于可视化湿颗粒流化床实验系统,研究了多种Geldart-D类颗粒在不同含液量时的流动特性变化规律,包含流型、床层压降、最小流化速度。实验结果表明:1)在湿流化床内,颗粒出现聚团结块行为,气泡呈现不规则形状;湿颗粒流化过程的稳定性较干颗粒床明显下降,床内近壁面区域易出现局部沟流。2)固定床阶段,由于空隙率的增加,相同气速条件下,湿颗粒床层压降低于干颗粒;基于厄贡公式,得出了湿颗粒固定床床层压降的计算方法。3)湿颗粒的最小流化速度U_(mf)高于干颗粒,且随粒径d_p的增加而增加;导出了预测D类湿颗粒最小流化速度的半经验公式,Re_(mf)=0.279.Ar^(0.5),该式计算结果与实验测量结果偏差小于15%。In the present work, a visual wet granular fluidized bed setup is established. Fluidization characteristics of various Geldart-D particles with different liquid contents are investigated in this experimental system, containing flow pattern, pressure drop and minimum fluidization velocity. Some notable conclusions can be obtained from the experimental results. 1） In the wet fluidized bed, agglomeration behavior for wet particles and bubbles with irregular shapes can be observed apparently. Meanwhile, the stability of wet granular flow process is lower than that of dry granular bed. In the region near the wall, local channeling is easy to happen. 2） At the stage of fixed bed, bed pressure drop for wet particles is smaller than that for dry particles due to the increases of voidage. Based on the Ergun formula, the calculating method of pressure drop for wet granules fixed bed is proposed. 3） The minimum fluidization velocity Umf for wet granular is higher than that for dry particles. The Umf for wet particle increases with the increase of particle size dp. A semi-empirical correlation, Remf = 0.279. Ar0.5, is developed to predict the Umf of the wet particles. The predictions calcu- lated by this correlation agree well with the present experimental results with the error of less than 15%.

关 键 词：湿颗粒 流化床 床层压降 最小流化速度 

分 类 号：TK123[动力工程及工程热物理—工程热物理]