Abstract: The internal flow field characteristics in a central tornado flow stirred tank are simulated qualitatively based on the computational fluid dynamics, the effects of angle of logarithmic spiral deflector, degree of polar angle, initial radius and height of deflector on the flow field in the tank examined, and the deflector structure is optimized for production of nanometer magnesia with the tank. The results show that the dimensions of deflector have significant effect on the flow field. When the internal diameter of stirred tank is 300 mm, the six-straight-blade-disk turbine used, the angle of logarithmic spiral deflector 45o, the polar angle 60o, the initial radius 20 mm, and the height of deflector 30 mm, two circular flow patterns form, the effect of tornado flow is obvious and that of mixing better. Such optimization has been verified in the experimental preparation of nanometer magnesia.

Key words: central tornado flow stirred tank, logarithmic spiral deflector, structural optimizatio, numerical simulation, magnesia

摘要： 运用计算流体动力学方法对中心龙卷流型搅拌槽内部流场进行数值模拟，研究了对数螺旋导流板角度、极角角度、初始半径、导流板高度对搅拌槽内流场的影响，以优化设计用于生产纳米氧化镁的搅拌槽导流板结构. 结果表明，对数螺旋导流板几何尺寸对宏观流场影响显著，当搅拌槽内径300 mm、桨叶为六直叶圆盘搅拌桨、对数螺旋导流板角度45o、极角角度60°、初始半径20 mm、导流板高度30 mm时，搅拌槽内整体流场形成2个循环流动，龙卷流效果明显，混合性能较好，并在纳米氧化镁制备实验研究中得到验证.

关键词: 中心龙卷流型搅拌槽, 对数螺旋导流板, 结构优化, 数值模拟, 氧化镁