单、双溢流管旋流器流场特征及分离性能研究

普通旋流器完成一次分级只能得到细颗粒的溢流和粗颗粒的底流，无法实现窄粒级精细分级要求。为了使一次分级可以获得多个细粒径、窄粒级产品，提出了一种双溢流管旋流器，为探明旋流器内流场特征及分离性能，采用数值模拟和试验研究对比研究了双溢流管旋流器和普通单溢流管旋流器内速度场、压力场、粒度场及分离性能。数值模拟结果表明：具有双溢流管结构的旋流器经过一次分离可以获取内溢流、外溢流和底流3种粒级产品。相比于单溢流管旋流器，双溢流管旋流器的切向速度和内部静压力更大；径向速度、轴向速度和湍动能更小，说明双溢流管旋流器可以强化分离过程，有利于分离性能的提高。试验验证结果表明：相较于单溢流管旋流器，双溢流管旋流器底流浓度降低了8.3个百分点，底流产率增大了3.25个百分点，内外溢流产品中-45 μm的颗粒累积含量增加了1.15个百分点，综合分级效率提高了1.26个百分点。研究结果可为多产品窄粒级旋流分离装备及工艺的研发提供一定的参考。

Study on the Flow Field Characteristics and Separation Performance of the Single and Double Overflow Pipe Hydrocyclone

The ordinary cyclone could only get the overflow of fine particles and the underflow of coarse particles in the once classification， difficult to achieve the requirements of fine classification of narrow particles. The double overflow pipe hydrocyclone was designed in order to obtain the fine particle size and narrow grain products in the once classification. The comparative study of the velocity field and pressure field in the cyclone， the granularity of field and separation performance of the single and double overflow pipe hydrocyclone were conducted by numerical simulation and experimental study. The numerical simulation results showed that the hydrocyclone with double overflow pipe structure could obtain three kinds of productions including internal overflow， external overflow and underflow after once separation. Compared with the single overflow pipe hydrocyclone， the tangential velocity and internal static pressure of the double overflow cyclone are higher， while the radial velocity， axial velocity and turbulent kinetic energy are smaller， indicating that the double overflow pipe structure can strengthen the separation process and improve the separation performance. The experimental results showed that compared with the single overflow pipe hydrocyclone， the underflow concentration of the double overflow pipe hydrocyclone decreases by 8.3 percentage points， and the yield of the underflow increases by 3.25 percentage points. The cumulative particle contents below 45 μm in the internal and external overflow product increases by 1.15 percentage points， and the comprehensive classification efficiency increases by 1.26 percentage points. The research results could provide a certain reference for the research and development of narrow-particle cyclone separation equipment and technology for multiple products.