液固流态化流区及其变迁

Flow Regimes and Their Transition in Liquid-Solid Fluidized Bed

本文在两种不同的有机玻璃床中(φ50×1200+φ100×500 mm),采用示踪粒子的方法,对液固流态化的流况及其随液速的变迁进行了研究。实验发现,液固流态化的流况随液速的增大,首先由固定床进入均匀散式流化;当液連增大到某一值(本文称为起始湍流速度)后,床层将进入湍流流化状态;再进一步增大液速,则床层变成下部湍流流化和上部均匀散式流化共存的流化状态。在本实验条件范围内,实验测得的湍流流化床层高度与有关的参数关系为而床层的总高可由Richardson方程式求得。

This paper reports the characteristics of flow regimes and their transitions with the liquid velocity in the liquid-solid fluidized bed. Experiments were performed in two plexiglass columns by means of tracer particles, one was 1200 mm in height and 50 mm in diameter and the other was 500 mm in height and 100 mm in diameter. It was found that flow regime was changed from fixed bed into particulate fluidization at first, with the increase of liquid velocity, and then into the turbulent fluidization after the liquid velocity reached to one point (termed as incipient turbulent velocity in this paper). When the liquid velocity increased furthermore, there was the fluidization with homogeneous particulate region in the upper section and turbulent region in the lower section, the height of which was determined experimentally as follows:H_t=1.28×10^(-3)(ρ_(?)/ρ_f)^(-0.232)Re_p^(0.793)α^(-0.213)While the total height of the bed can be obtained by using Richardson equation