基于粒子图像测速技术(PIV)及计算流体动力学软件(CFD-DEM)模拟方法对气固流化床中气泡演化特性及流场结构进行了研究。结果表明,初始颗粒在流化床内部的堆积,会对气体分布、气泡的生成及演化产生影响;进气时的气泡顶部存在一个区域,在其上方的颗粒被吹起,而其下方的颗粒会影响气泡底部颗粒的运动;气泡生成过程中,径向气体的运动基本呈中心对称,只有当气泡将要破碎时才会出现气体流向的偏移;当气泡面积变小到492 mm²后,又会生长到与初始气泡类似的大小,两者的面积差异只有1.7%。

The bubble evolution characteristics and flow field structure in gas-solid fluidized bed are studied by means of the particle image velocimetry technique (PIV) and computational fluid dynamics software (CFD-DEM) simulation method.The results show that the accumulation of initial particles inside the fluidized bed affects the gas distribution,bubble generation and evolution.In addition,a zone appears at the top of the bubble when the gas feeds,above which the particles are blown up,and below which the particles fall due to the vortex created by the bubble and the showering down inside the bubble,and collide with the particles at the bottom of the bubble.During bubble generation,the motion of the radial gas is basically centrosymmetric,and only when the bubble is about to break will there be a shift in gas flow direction.After the bubble area becomes smaller to 492 mm²,it will grow back to a similar size as the initial bubble,and the area difference between the two is only 1.7%.

曲家宁(1997-),女,硕士生,研究方向为多相流体流动与分离,qujianing1997@163.com。