喷动床空隙率分布

STUDIES ON THE FLUID CHARACTER OF SPOUTED BED

对塔径为１８２ｍｍ的喷动床，设计了可更换口径的直管式喷嘴，使用光导纤维仪实测小米和尿素等物料床层局部空隙率分布．结果表明，床内流动状态可分为喷动区、密相区、环形区和壁效应区４个区域．密相区空隙率变化很小，不随操作条件改变，且与静床空隙率相当，对喷动床操作的稳定性起决定作用．

This paper describes a straight-pipe nozzle with changeable apertures designed fora spouted bed with a diameter of 182 mm to study the local-void distributions of the bed employingmillet and urea as test materials. The measurements of local-voidage were carried out with an optical fiber sensor. From the results of the investigation on voidages on the spouted bed it is foundthat the flow regime in the spouted bed can be divided into four different zones: spout zone, annular zone, dense phase zone and wall-effect -cone. Voidage of the dense phase zone was equivalent tothat of the packed bed and did not change with operating conditions. The dense phase played a dicisive role in forming a good spout state in the bed. The discovery of the dense phase zone willhave positive effects on the study of hydrodynamics of the spouted bed and its practical application.