基于FLUENT的微细赤铁矿颗粒絮凝过程的数值模拟

Numerical simulation of the flocculation process of fine hematite particles based on FLUENT

应用计算流体力学软件FLUENT对试验中不同搅拌转速下的水流流态进行三维数值模拟,以计算所得的紊动动能κ、有效能耗ε和微涡旋尺度λ作为评价絮凝是否充分的指标。通过烧杯试验和对其内水流流态的数值模拟,分析了搅拌转速对絮凝效果的影响,建立了搅拌转速同沉降率E_s、整体平均有效能耗ε和微涡旋尺度λ之间的定量关系。烧杯试验中流体为浓度2%的微细(平均粒径21.35μm)赤铁矿矿浆,絮凝剂为食用玉米淀粉。结果表明,数值计算所得的κ、ε和λ能合理解释絮凝搅拌转速对絮凝效果的影响。

The CFD （Computational Fluid Dynamics） software FLUENT is applied to 3D numerical simulation of the water flow pattern in different agitation speed under test. Calculated numerical values of the turbulent kinetic energy k the effective energy dissipation ε and microvortex scale k are defined as the criterions for evaluating the flocculation action whether it is enough or not. Through the jar test and numerical simulation of the flow pattern in it, influence of the stirring speed on the flocculation is analyzed and the quantitative relation among the stirring speed settlement ratio Es, the overall average effective energy dissipation ε and the microvortex scale k is established. The liquid used for the beaker test is of fine hematite pulp with the concentration of 2% and the average particle size of 21.35μm, while maize starch is used as flocculant. With calculated values of k, ε and k in the paper, the influence of the agitating speed on the flocculation action can be reasonably explained.