CAJ | 학술논문

颗粒的循环特性是循环流化床研究的重点及热点之一，在建立颗粒循环时，颗粒循环由非稳态向稳态过渡。本文在循环流化床实验装置中，采用摄像法和压力检测法研究了不稳定颗粒循环条件下颗粒流动结构和各段压降的变化情况。首次发现了不稳定颗粒循环状态下的颗粒振荡循环现象及其具有的两个特征：下降段、提升段气固流动结构呈周期性变化；下降段压降 pd和提升段压降 pr周期性波动且 pd>pr和 pd<pr交替出现。进一步对颗粒振荡循环过程进行受力分析，建立了颗粒振荡周期的计算公式。研究还发现在颗粒藏量一定的条件下，循环气流量或颗粒循环段阀门开度大于某一临界值时才能诱发颗粒振荡循环；颗粒振荡循环周期随着循环气流量的增大而增大，与阀门开度无关。研究结果为动态颗粒循环建立过程的研究奠定了基础，有助于快速地建立颗粒的稳定循环。
과립적순배특성시순배류화상연구적중점급열점지일，재건립과립순배시，과립순배유비은태향은태과도。본문재순배류화상실험장치중，채용섭상법화압력검측법연구료불은정과립순배조건하과립류동결구화각단압강적변화정황。수차발현료불은정과립순배상태하적과립진탕순배현상급기구유적량개특정：하강단、제승단기고류동결구정주기성변화；하강단압강 pd화제승단압강 pr주기성파동차 pd>pr화 pd<pr교체출현。진일보대과립진탕순배과정진행수력분석，건립료과립진탕주기적계산공식。연구환발현재과립장량일정적조건하，순배기류량혹과립순배단벌문개도대우모일림계치시재능유발과립진탕순배；과립진탕순배주기수착순배기류량적증대이증대，여벌문개도무관。연구결과위동태과립순배건립과정적연구전정료기출，유조우쾌속지건립과립적은정순배。
During the process of solids circulation establishment in circulating fluidized beds (CFBs), the solids circulation goes through a transition from an unstable state to a stable one. In this work, the stability of solids circulation in a CFB with limited bed inventory is studied by using a pressure transducer and a digital camera. The work reveals an interesting phenomenon, termed as oscillation circulation behavior of solids transportation between the riser and the downer through a solid control valve. Two important features are noted from the experimental results. Firstly, the gas-solid flow pattern in the riser and the downer is in transition between various fluidization regimes. Secondly, the pressure drop of the riser and the downer fluctuates periodically alternating betweenpd>pr andpd<pr. The calculation model of oscillation cycle is deduced by force analysis of oscillation process. Further study shows that solids oscillation behavior is controlled by the gas flow and valve opening. With a constant bed inventory, the oscillatory behavior is only initiated by the critical gas flow or valve opening. The oscillation cycle decreases with the decrease in gas flow but remains constant with varying solid control valve opening. The amount of solid transfer decreases with the decrease in gas flow and valve opening, while the pressure drop fluctuation decreases.