摘要
通过固体颗粒和水的混合物在搅拌器中进行搅拌使固体颗粒粉碎至一定粒度的试验，研究了各种搅拌参数如液固比、搅拌桨叶端速度、桨叶直径、转速、层数、宽度、时间、液深对颗粒粉碎效果的影响。提出在搅拌过程中，除了循环流动及剪切外，其碰撞作用在某些过程中占了重要地位。分析指出在搅拌粉碎中存在极限粒径，给出了极限粒径和叶端线速度的关系式，解释了随着搅拌时间的增加，粉碎效率逐渐降低及在一定范围内固体含量增加使粉碎效率提高的现象。结合循环流动、剪切及碰撞原理，对减小液深，增加直径、转速及桨叶层数可减少搅拌时间进行了分析，并得出桨叶宽度对颗粒粉碎效果影响甚微的结论。提出了设备放大原则和放大后搅拌时间的近似计算公式。新设计的搅拌器用于生产实践后与原有装置相比提高了效率，降低了能耗。
he effects of various agltal ion Parameters,such as liquid/solid ratio,end velocity of impeller,di-ameter of impeller.rotating speed, layernumber.width.time and liquid depth.etc,on porticle-crashingeffectiveness are studied through experiments.by which a mixture containing solid particles and wateris agitated.so the particles are crashed into certain size.It is proposed that the collision is also an impor-tant factor during some agitation processes besides recireulation flow and shearing.By theoretical anal-ysis,a concept of limit diameter of particle is explained for the agitation crashing process and a rcla-tionship fornaula is also developod between the above limit diameter and end velocity of impeller. andsome phenomena are described as that the crashing effectiveness will be reduced with agitating time in-crease and will be inereased with particle content increase in certain range.lntegrating the recirculationflow,shearing and collision principles,the reduction of agitatins time due to decrcains depth of liquid,incrcasing diameter,rotating speed and layer number is analyzed,and a conclusion that the width ofimpeller has a little effect on the particle crashing effectiveness is obtained. Finally ,the scaling-up phi-losophy of equipment and an approximate calculation methed of agitating time for a scaled-up equip-ment are proposed.The Commercial application shows that the agitator designed by new method has ahigher effectiveness and lower energy consumption as compared with those of the existing one.
出处
《化学工程》
CAS
CSCD
北大核心
1995年第2期34-39,共6页
Chemical Engineering(China)
关键词
搅拌
悬浮液搅拌
搅拌器
碰撞作用
固体颗粒
agitation,suspension agitation,collision crashing,scaling-up of agitator
