摘要
应用电荷耦合器件CCD(charge coupled devise)测量和图像处理技术,定性和定量研究了热模汽-液-固三相自然循环流化床蒸发器中固体颗粒浓度和速度的轴、径向分布以及其随热通量、固体颗粒加入量等操作参数的变化规律。热通量的变化范围为2179.8W穖-2到6624.2W穖-2,固体颗粒的体积分率的变化范围为0.5%到2%。结果表明:在液-固两相区,固体颗粒浓度在轴向和径向的分布较为均匀;随着热通量的增加,加热管中固体颗粒的浓度逐渐降低,循环管中固体颗粒的浓度逐渐升高,并且两者均随固体颗粒加入量的增加而升高;固体颗粒的速度在轴向上较为接近,其在循环管中的速度高于在加热管中的速度,并且两者均随热通量的增加而升高;固体颗粒加入量对其速度有增强和阻碍两方面的作用。
In a heated vapor-liquid-solid three-phase circulating fluidized bed evaporator, the axial and radial distributions of holdup and velocity of the solid particles were studied qualitatively and quantitatively under different heat fluxes and addition amounts of solid particles. CCD measurement and image dealing techniques were used. The experimental results show that the flow is natural circulation in the fluidized bed and the axial and radial distributions of the solid particles holdup are fairly uniform in the liquid-solid two-phase region. As the heat flux increases, the solid particles holdup gradually reduces in the heating tube, whereas gradually increases in the circulating tube, moreover, both holdups increase as the amount of added solid particles is increased. Along the tube axis, the velocity of the solid particles relatively approaches equal and the velocity of the solid particles in the circulating tube is higher than that in the heating tube, and both increase as the heat flux increases. The amount of added solid particles has both advancing and impeding effects on the velocity of solid particles.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2004年第5期564-570,共7页
Journal of Chemical Engineering of Chinese Universities
基金
国家青年自然科学基金(20106012)。
关键词
汽-液-固三相
循环流化床
蒸发器
固体颗粒
CCD
Charge coupled devices
Evaporators
Fluidized beds
Heat flux
Two phase flow
Velocity
