循环流化床稀相区流动结构的实验研究

应用粒子动态分析仪，对方形管循环流化床的稳定段颗粒相的流动结构进行了实验研究。颗粒浓度呈中心稀，壁面附近浓，且边角效应明显；颗粒速度的垂直分量中心向上，壁面附近向下，水平分量则指出／向壁面和角落。颗粒浓度和速度分布特性证实了方形环核结构２的存在。颗粒相的湍流脉动量随着向壁面的靠近而降低，且表现出显著的各向异性特点。湍流相关脉动量在床中心大，边壁低，且在床的中心区域呈现出各向异性而在边壁区则表现了各

Flow Structure in Circulating Fluidized Bed Riser

An extensive study was carried out of turbulent flow structure in a circulating fluidized bed (CFB) riser of square cross section with PDA.Particle concentration is high at the wall and low in the core and the corner effects are significant.The vertical component of particle velocity is upward in the core and downward along the wall,whereas horizontal component is toward the corner and the wall.Concentration and velocity profiles confirms the core annulus structure for CFB.Root mean square velocity and correlated velocity flunctuation,that is turbulent kinetic energy and Reynolds stress of the particle,is strong in the core and weak at the wall.The former is anisotropic in the tested cross section and the latter is anisotropic in the core and isotropic at the wall.