Abstract: The high gravity field and turbulent shear field can strengthen the classification of micron particles in micro hydrocyclone. In order to analyze the classification performance of micron particles with hydrocyclones,the effect of inlet velocity and underflow ratio on hydrocyclone classification were studied by combination of experiment and numerical simulation. The Reynolds stress model was used to simulate the flow field of micro hydrocyclone in numerical simulation,the micro hydrocyclone of 20mm in diameter was used to classify granular materials whose particle size distribution was 2-50μm in the experiments. The results showed that with the increase of inlet velocity,the cut size x₅₀ decreases,the x₅₀ is 4.8μm,and the classification precision H increases,the H is 0.45. With the increase of underflow ratio R_f,the tangential and radial velocity are not significantly changed. The settling velocity of particles has no obvious change in the hydrocyclone,but the axial velocity will decrease,which makes the residence time of particles increase in the hydrocyclone. The classification efficiency improves. When underflow ratio R_f is less than 0.6,with the increase of R_f,the cut size x₅₀ decreases. The x₅₀ is 4.7μm and the classification precision H increases,the H is 0.6. When underflow ratio R_f is greater than 0.6,the cut size x₅₀ increases,and the classification precision H decreases.

Key words: micro hydrocyclone, numerical simulation, particle size distribution, granular materials

摘要： 微型旋流器中的超重力场和剪切湍流场可以强化微米级颗粒的分级。为了分析旋流器的微米级颗粒分级性能，本文通过试验与数值模拟相结合的方法研究了入口速度和底流分率对旋流分级的影响。数值模拟方面使用雷诺应力模型模拟了微型旋流器内的流场，试验方面使用直径为20mm的微型旋流器来分级粒度分布为2～50μm的颗粒物料。结果表明，随着入口速度的增大，分割粒度x₅₀减小，可达4.8μm，分级精度H提高，可达0.45；随着底流分率R_f的增大，不会显著改变切向和径向速度，颗粒在旋流器内的沉降速度变化不大，但轴向速度会减小，使得颗粒在旋流器内的停留时间增加，分级效率提高；当底流分率R_f < 0.6时，随着R_f的增大，分割粒度x₅₀减小，可达4.7μm，分级精度H提高，可达0.6；当底流分率R_f > 0.6时，分割粒度x₅₀增大，分级精度H降低。

关键词: 微型旋流器, 数值模拟, 粒度分布, 颗粒物料