School of Chemical Engineering and Technology,China University of Mining & Technology,Xuzhou　 221116,China

针对旋流-静态微泡浮选柱进行了气-液两相流非稳态数值模拟,分析了旋流单元的流动特征及矿化方式,然后采用2台高速动态摄像机连用的方法,进行了气泡、颗粒在旋流流场下的三维运动轨迹及碰撞行为的测量,得出了与数值模拟相一致的结论。主要结论如下:在旋流单元,气、液两相的流动均以切向运动为主,锥上区域具有向心和向上的趋势,锥内区域具有离心趋势,锥下区域液相旋流向下运动;气、液两相具有轴向和径向速度差,切向速度虽然不具有明显相间速度差,但其在径向上的梯度极高;锥内区域气含率最高,在10%~13%,锥下区域气含率小于1%。旋流单元的分选作用以分离尾矿和分选中等粒级矿物为主,气泡与颗粒的矿化方式体现为绕轴心旋转过程中发生的轴向与径向的"逆流碰撞",锥下区域不具备矿化条件,旋流强度是影响该单元分选和分离效率的重要因素。

A gas-fluid unsteady numerical simulation was conducted for a large-scale floatation column in this study. Based on the simulation results,the flow field feature of cyclonic unit was analyzed and the mineralization characteris- tic was discussed in terms of the slip velocity between gas and fluid phase. Then movement of bubble and particle was measured with two high speed cameras. The collision behavior and 3D motion trajectory were obtained,which agrees well with the numerical simulation results. The main conclusions on cyclonic unit are as follows:both gas and liquid phase moves tangentially inside of cyclonic unit,and the movement above the cone has the tendency of centripetal and upward,while the centrifugal trend exists in the cone inner area. Below the cone,the fluid moves downward spirally. There are obvious axial and radial velocity difference at the same location between gas and liquid. Although the tan- gential velocity looks the same,it presents a high gradient in radial direction. As to the gas holdup,the value remains 10% -13% in the inner area of cone,while lower than 1% below the cone. As an important separation unit,the cy- clonic unit undertakes the separation of tailings and the recovery of middle-size minerals. The mineralization behaves as the combination of “countercurrent collision” in axial and radial directions in the swirling process. The area below the cone does not have the condition of mineralization. Swirling intensity dominates the separation efficiency of cyclonic unit.

国家自然科学基金资助项目(51404264)；中央高校基本科研业务费专项资金资助项目(2014QNB16)；

Yan Xiaokang,Liu Yu,Zhang Xiubao. Numerical simulation and experimental measurement on the cyclonic flow field of a cyclonic-static micro-bubble flotation column[J]. Journal of China Coal Society,2016,41(6):1560-1567.