脉动气流辅助流化下双组分颗粒的混合特性研究  

Particle Mixing and Segregation of Binary Mixtures in Fluidized Beds with Additional Pulsating Air Flow

作　　者：李占勇[1] 潘波[1] 高新源[1] 胡娅君[1] 

机构地区：[1]天津科技大学机械工程学院,天津300222

出　　处：《农业机械学报》2015年第3期247-253,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家高技术研究发展计划(863计划)资助项目(2012AA021303)

摘　　要：脉动流化对气固接触和热质传递有一定的优势。分别以相同密度不同粒径以及不同密度相同粒径两类颗粒体系为研究对象,以Ashton混合指数和沉积组分分布为评定依据,实验研究了不同脉宽比下脉动气流辅助流化对颗粒混合程度的影响,并与普通流化床进行了比较。结果表明:在平均气速较低的情况下,添加辅助脉动气流有助于促进颗粒混合,同时得出颗粒密度差别对双组分颗粒混合的影响大于颗粒直径差别对其的影响。Pulsating fluidization has the advantages of high level contact of gas-solid and good mass and heat transfer. This paper presents the studies on two types of binary particles ： identical sizes but different densities, and identical densities but different sizes. The experiments were carried out in a two- dimensional fluidized bed which was made of plexiglas with the size of 200 mm （length） × 20 mm （width） × 1 000 mm （height）. Two air streams, steady flow and pulsating flow, were introduced into ttle fluidized bed to compare their effects on the mixing of particles. Experiments also investigated the mixing characteristics in different pulse intermitteneies in terms of Ashton mixing index and the distribution of jetsam concentration. The results show that pulsating flows imposed on conventional fluidization can improve particle mixing at a lower average gas velocity. It is also found that the Ashton mixing index of equal densities binary mixtures is about 18% bigger than that of unequal densities binary mixtures. Thus the effect of density difference on particle mixing is more significant than the influence of size difference for binary particles.

关 键 词：脉动流化床 混合特性 脉宽比 

分 类 号：TQ051.13[化学工程]