摘要
流化床燃烧理论对颗粒形貌因素的考虑是引入球形度的概念,但球形度不能区别出不同的颗粒形态.本研究比较了描述颗粒形貌的球形度与Zingg指数,认为Zingg指数可以很好的区分出颗粒的片状和棒状形态.通过冷态流化实验发现非球形颗粒临界流化速度要小于相同直径下的球形颗粒,但流化质量较差.非球形颗粒比球形颗粒床面消失滞后,出现流化延迟现象.根据非球形颗粒流化床的床层特点,定义流化惰性系数来评价颗粒的流化质量,片状颗粒的流化惰性系数与Zingg指数有较好的拟合关系,可以使用惰性系数对片状颗粒的临界流化速度进行修正.
Sphericity can not be used to describe morphology of bed material particles perfectly even though it is adopted in fluidization theory for a long time.In another aspect,Zingg index is easy to measure and convenient to recognize rod or chip-shaped particles.Cold experiment shows that non-spherical particles have bad fluidized quality and a lower minimum fluidized bed velocity than spherical particles.The superficial gas velocity of fluidizing bed surface is described by a new concept of inert fluidizing factor according to the characteristics of non-spherical bed material.Inert fluidizing factor and Zingg index have a better fitting relation with superficial gas velocity,minimum fluidized velocity of non-spherical particles can be verified through inert fluidizing factor.
出处
《过程工程学报》
CAS
CSCD
北大核心
2006年第z2期368-374,共7页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:50476082)
关键词
颗粒形貌
片状
流化床
临界流化速度
流化质量
particle morphology
chip-shaped particle
minimum fluidized velocity
fluidization
