三叶片潜水搅拌机的数值模拟

Numerical simulation of submersible mixer with three blades

为研究潜水搅拌机性能,应用三维造型软件Pro/E建立搅拌机叶片的三维实体模型,利用Gambit软件对污水处理水池进行非结构化四面体网格划分,在计算流体动力学软件Fluent 6.3平台上,采用动坐标系、RNG k-ε湍流模型和SIMPLE算法,对潜水搅拌机搅拌的污水处理池进行数值模拟,计算全池内流体的宏观流场与各个截面的速度分布,分析潜水搅拌机的轴向有效推进距离与水体截面有效扰动半径,同时对潜水搅拌机的功率进行了研究.计算结果表明:潜水搅拌机能使污水处理池内流体形成连续循环水流,流体轴向推进,径向扩散;池内流体充分搅拌,池内流体流速基本都在0.3 m/s以上,符合潜水搅拌机工作要求,故潜水搅拌机与该污水处理池相匹配;同时确定该潜水搅拌机可选取功率为3.0 kW的电动机.利用此方法,可为潜水搅拌机的实际工程应用提供一定参考依据.

To study the performance of a submersible mixer,the fluid flow driven by the mixer in a sewage pool was simulated using Fluent 6.3.An unstructured tetrahedral mesh was generated by Gambit.The MRF technology,k-ε turbulence model and SIMPLE algorithm were adopted in the simulation.The entire fluid flow field and the velocity distribution in each cross-section were analyzed.The shaft-power,axial and radial distance affected by the mixer were studied as well.The results showed that a continuously recirculation current of water is established in the pool by the submersible mixer,namely the fluid is propelled in the axial direction initially and diffused in the radial direction.Consequently,the water in the pool is agitated throughout and the flow velocity is usually higher than 0.3 m/s,which complies with the working requirement of the mixer.It suggests the submersible mixer matches the sewage pool and makes sure that a motor with 3.0 kW rate power is suitable for it.Such a numerical flow simulation method can provide a reference for practical applications of submersible mixers.