双曲面搅拌器翼型及安装高程对搅拌性能的影响

Influence of airfoil and installation elevation of hyperboloid agitator on mixing performance

采用NX软件建立实体模型,并用Fluent 18.0软件进行三维湍流分析,通过非结构化网格和动坐标系技术,选用标准k-ε湍流计算模型和SIMPLEC算法进行速度-压力耦合求解.在原有双曲面搅拌器翼型的基础上,对桨叶进行水平叠加,并计算了2种翼型下双曲面搅拌器在9 m×9 m×5 m的氧化池内的搅拌流场,对比分析了优化前后双曲面搅拌器桨叶附近流场变化和不同安装高程下特定区域的湍动能变化.双曲面搅拌器的桨叶延伸线为螺旋线,计算结果表明,其桨叶的迎水面作为直接与来流撞击的面,其最优应为螺旋线的凹侧且与转盘呈锐角的斜面,背水面最优为与转盘垂直的垂面,且背水面后增加一斜面可对加速后的水体起到整流作用,使搅拌器径向搅拌范围更大.安装高程H=1.0 m时,池内平均流速达到0.710 m/s,较优化前提升0.140 m/s,搅拌池底部区域平均湍动能达到0.021 J/kg,较优化前高0.008 J/kg.

NX software was used to establish the solid model,and Fluent 18.0 software was used to analyze the three-dimensional turbulence.Through unstructured grid and moving coordinate system technology,standard k-εturbulence calculation model and SIMPLEC algorithm were used to solve the velocity pressure coupling problem.On the basis of the original hyperbolic agitator airfoil,the blades were superimposed horizontally,and the mixing flow field of the hyperboloid agitator in the oxidation tank of 9 m×9 m×5 m under the two airfoils was calculated.The flow field near the blades of the hyperbolic stirrer before and after optimization and the turbulent kinetic energy change in the specific area under different installation heights were compared and analyzed.The blade extension line of hyperbolic stirrer was helix.The research and calculation show that the upstream surface of the blade is the surface directly impacting with the incoming flow,and the optimal one is the concave side of the spiral line and at an acute angle with the turntable.The optimal back water surface is the vertical plane perpendicular to the turntable.Adding an inclined plane behind the back surface can rectify the accelerated water body and make the radial mixing range of the agitator wider.When the installation elevation is H=1.0 m,the average velocity in the pool reaches 0.710 m/s,which is 0.140 m/s higher than that before optimization.The average turbulent energy in the bottom area of stirring tank reaches 0.021 J/kg,which is 0.008 J/kg higher than that before optimization.