潜水搅拌机内部压力脉动特性分析

为深入研究由叶轮内压力脉动引起的潜水搅拌机振动的内部流场特性,利用大型计算流体软件Fluent 6.3和大型网格专用软件Gambit,采用RNG k-ε湍流模型和 PISO算法和滑移网格技术与刚盖假定方法,对潜水搅拌机搅拌的污水处理水池三维非定常湍流流场进行了数值模拟,在研究了叶轮区域及水池内流体流场特性基础上,分析了潜水搅拌机内部压力脉动特性研究.研究结果表明:潜水搅拌机搅拌叶轮内部以及叶轮附近的流体具有很明显的周期流动变化,高压低速区和低压高速区均随着叶轮的旋转而发生周期转动.叶轮进出口以及内部的压力脉动频率以叶轮转频为主.研究结果可为潜水搅拌机的实际工程应用提供参考.

Analysis of characteristics of pressure fluctuation inside submersible mixer

For a thorough study on the vibration induced by pressure fluctuation inside a submersible mixer, the unsteady, three-dimensional turbulent flow driven by a specific submersible mixer in a se-wage treatment pool is simulated by using software-Fluent 6.3 and Gambit. The RNG k-ε turbulence model, PISO algorithm, rigid-lid approximation and sliding mesh are adopted in the simulation. The pressure fluctuation characteristics in the impeller of submersible mixer are clarified based on an examination of the unsteady flow field features in the impeller and pool. It is shown that the flow of the fluid inside the impeller and in the vicinity of impeller exhibits an obvious periodic feature, i.e. the fluid domain with high pressure and low relative velocity and the domain with low pressure but high relative velocity vary periodically with the rotating impeller. The pressure fluctuation frequency of the fluid in the impeller entrance, outlet and inside the impeller is closely related to impeller rotational frequency, and the predominant frequency is 2 times the blade passing frequency. The results may provide a reference for application of the mixers.