旋流器底流口直管段长度对分离性能的影响研究

底流口直管段是旋流器的重要部件，为了探明底流口直管段长度对旋流器分离性能的影响规律，采用数值模拟和试验方法，对比研究了底流口直管段不同插入深度对旋流器压力场、速度场、湍动能的影响。模拟结果表明：随着直管段插入深度绝对值的增加，流场静压力、切向速度、湍动能均有不同程度增大，可以有效增大离心强度，强化分离效果，而径向速度随着直管段插入深度绝对值的增加有所减小，径向速度的减小有利于分级精度的提高；试验结果表明：进料压力为0.1 MPa、进料浓度为10%、进料中位粒径为16.75 μm时，随着底流口直管段长度由0 mm增加到80 mm，底流浓缩倍数由4.61倍提高到6.48倍，底流产品中位粒径由49.32 μm增大到65.88 μm，溢流产品中位粒径由8.57 μm增加到21.16 μm，溢流产品细度变大，分离粒度增大，综合分级效率较传统旋流器提高了13.85个百分点。

The Influence of Straight Pipe Length of the Bottom Outlet on the Separation Performance of the Hydrocyclone

The straight pipe length of the bottom outlet is the important section. In order to find out the influence law of the straight pipe length of the bottom outlet on the separation performance of the hydrocyclone， the influences of different insertion depths of the underflow straight section on the pressure field， velocity field and turbulent kinetic energy of the cyclone were studied by numerical simulation and experiment. The simulation results showed that with the increase of the absolute value of straight pipe inserted into the depth， the static pressure， tangential velocity and turbulent kinetic energy of flow field appears varying degrees of increase， which could effectively increase the centrifugal strength and strengthen the separation effect. While the radial velocity decrease with the increase of the absolute value of straight pipe inserted into the depth， and the decrease of the radial velocity was beneficial to the improvement of the accuracy of classification. The test results showed that with the feeding pressure of 0.1 MPa， the feeding concentration of 10% and the median particle size of 16.75 μm， the underflow concentration times increase from 4.61 times to 6.48 times and the median particle size of the underflow product increases from 49.32 μm to 65.88 μm with the straight pipe length of the underflow port increasing from 0 mm to 80 mm. The median particle size of the overflow product increased from 8.57 μm to 21.16 μm， the fineness of the overflow product became larger， the separation particle size increased， and the comprehensive classification efficiency was increased by 13.85 percentage points compared with the traditional hydrocyclone.