涡流空气分级机补气结构设计及流场仿真  

Air supply structure design and flow field simulation of turbo air classifier

作　　者：顾毅楠 吴永泽 俞建峰 钱陈豪 化春键 蒋毅 GU Yinan;WU Yongze;YU Jianfeng;QIAN Chenhao;HUA Chunjian;JIANG Yi(School of Mechanical Engineering,Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment&Technology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学机械工程学院,江苏省食品先进制造装备技术重点实验室,江苏无锡214122

出　　处：《中国粉体技术》2024年第5期158-170,共13页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:51905215;江苏省研究生科研与实践创新计划项目,编号:KYCX23_2553;江苏省食品先进制造装备技术重点实验室自主研究课题资助项目,编号:FMZ202302。

摘　　要：【目的】针对涡流空气分级机补气效果不佳的问题,寻求最优补气方案。【方法】采用Fluent软件对涡流空气分级机进行流场仿真,探究不同补气结构对气流滞留能力、均匀性、分散性的影响,以及对应分级机的颗粒分级效果。【结果】仿真结果表明,Model 2在导流罩上方增添挡风环结构,有效遏制气流流失,显著提升补气气流在锥壳内部的滞留时间,d50较Model 1减小0.62μm;Model 3在补气结构内添置导流叶片,减弱气流冲击并增加气流分散效果,d50较Model 2减小2.88μm;Model 4、Model 5将补气结构进出气区域在竖直方向上错开,保证气流有充足的滞留空间,进而阻止气流快速扩散;Model 5采用补气结构出气区域下置方案,利用锥壳壁面为气流导向,轴向速度分布更加合理,气流分散性及分布均匀性最好。【结论】对比5种补气结构的粒径累积占比分布曲线,Model 5的d50为28.5μm,略大于Model 3的27.3μm,但在0~20μm粒度区间段,Model 5的曲线位于Model 3下方,说明Model 5对大米粉细颗粒的分级效果优于Model 3,综合来看,Model 5对大米粉的颗粒分级效果最佳。Objective To address the poor performance of turbo air classifier,five different air supply structures were designed to find the optimal scheme to improve its classification efficiency.Method The accuracy of the calculation model was verified through grid independence analysis and eddy current classification experiments using rice flour.The flow field of the turbo air classifier was simulated using Fluent software to explore the influence of different air supply structures on air retention capacity,uniformity,and dispersion.A discrete phase model(DPM)was used to simulate the motion trajectory of rice flour particles.The cumulative distribution of particle size at the discharge of the classifier was analyzed to determine the influence of different air supply structures on rice flour classification.Results and Discussion Simulation results revealed that adding a windshield ring structure above the cone fairing in Model 2,based on Model 1,effectively reduced direct air loss from the cone shell wall,significantly increased the residence time of the replenished air in the cone shell,and reduced d50 by 0.62μm compared with Model 1.Model 3,which added a flow guide blade to the air outlet plane of the air supply structure on the basis of Model 2,weakened air impact and increased air dispersion.The fluctuation in axial velocity value in Model 3 became smaller,and the d50 was 2.88μm lower than that of Model 2.However,insufficient space in the air supply structure reduced airflow retention time and affected air replenishment.A completely different air supply structure was adopted in Models 4 and 5 from Model 3,with staggered inlet and outlet areas in the vertical direction to ensure sufficient retention space for airflow,thereby improving the residence time.The d50 of Model 4 was 30.22μm,which was 2.92μm higher than Model 3,indicating suboptimal air-replenishment performance.In contrast,Model 5 adopted a downsetting scheme for the air outlet area of the air supply structure,using the conical shell as an air flow guide.M

关 键 词：涡流空气分级机 补气结构 气流滞留能力 均匀性 分散性 

分 类 号：TB44[一般工业技术] TQ324.8[化学工程—合成树脂塑料工业]