横向流对搅拌浮选槽流动特性影响的CFD数值模拟

CFD numerical simulation of influence of lateral flow on flotation machine flow field

浮选机在受到横向进入的矿浆时,其流场特征也不尽相同。基于计算流体力学(computational fluid dynamics,CFD)方法,数值模拟KYF型浮选机在横向流(清水)作用下,分析不同流量对浮选槽流动循环特性、湍动能的影响。同时,根据叶轮监测点压力值周期性波动特点,通过漩涡强度准则的涡识别方法分析不同压力点时刻叶轮区域涡系结构的变化。结果表明:横向流量的增加,浮选槽上部再循环作用会有一定的减弱,每个定子间隙的径向流速度峰值关于横向流轴线呈现明显的不对称性,顺流侧的径向速度峰值整体低于逆流侧。横向流量的增加也会引起混合区和运输区的湍动能增大,此外,横向流对浮选机因叶轮旋转搅拌引起流场中的旋转涡流起到抑制作用。

When the flotation machine is subjected to lateral flow of slurry,its flow field characteristics will also change significantly.Based on Computational Fluid Dynamics(CFD)method,the KYF flotation machine was numerically simulated with the horizontally entering slurry(fresh water),and the effects of lateral flow rate on the flow cycle characteristics and turbulent kinetic energy were studied.According to the periodic fluctuation characteristics of the pressure value of the impeller monitoring point,the vortex identification method of swirling strength criterion was used to analyze the change of the vortex structure of the impeller region before and after the flow change.The results show that with the increase of lateral flow,the circulation effect on the flotation tank is weakened to a certain extent.The peak value of radial flow velocity of each stator gap shows a significant asymmetry about the transverse flow axis.The radial velocity peaks on the downstream side are generally lower than those on the upstream side.The increase of the lateral flow will also increase the turbulent kinetic energy in the mixing zone and the transport zone.In addition,the swirling vortex in the flow field caused from the impeller rotation is suppressed by the lateral flow.