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x_(50)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。
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 20 mm 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 x（50） decreases,the x（50） is 4.8μm,and the classification precision H increases,the H is 0.45.With the increase of underflow ratio Rf,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 Rf is less than 0.6,with the increase of Rf,the cut size x（50） decreases.The x（50） is 4.7μm and the classification precision H increases,the H is 0.6.When underflow ratio Rf is greater than 0.6,the cut size x（50） increases,and the classification precision H decreases.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2017年第12期4371-4377,共7页
Chemical Industry and Engineering Progress
关键词
微型旋流器
数值模拟
粒度分布
颗粒物料
micro hydrocyclone
numerical simulation
particle size distribution
granular materials
