负压气力输送系统弯管内流场数值模拟与设计优化

Numerical Simulation and Design Optimization of Flow Field in Elbow in Negative Pressure Pneumatic Conveying System

在负压气力输送系统长期使用中,会因为弯管磨损而产生漏料。采用有限元分析软件ANSYS ICEM,对弯曲半径R与管道内径D的比值分别为2、 3、 4、 5的弯管内气固两相流动情况进行数值模拟,揭示不同R/D下,气固两相的体积分数、速度、受压区域壁面切应力及颗粒拟温度等流场分布信息,分析弯管形状参数对磨损的影响。数值模拟结果表明,R/D=4的弯管设计结构合理,弯管内固相体积分数、粉体速度最大值、受压区域切应力最大值均最小,粉体的脉动强度最低,有利于减缓弯管磨损。依据数值模拟分析结果,结合生产实际提出了减缓弯管磨损、延长弯管使用寿命的设计优化方法。

In the long-term use of a negative pressure pneumatic conveying system,material leakage will occur due to elbow wearing. The finite element analysis software ANSYS ICEM was used to simulate the gassolid two-phase flow in the elbow with the ratio of bending radius R to pipe inner diameter D of 2,3,4,and 5,respectively,to reveal the flow field distribution information of gas-solid two-phase volume fraction,velocity,wall shear stress in the pressure area and particle pseudo temperature under different R/D,and to analyze the influence of elbow shape parameters on wearing. The numerical simulation results show that the elbow with R/D=4 has a reasonable design structure. The volume fraction of solid in the elbow,the maximum value of powder velocity,the maximum value of shear stress in the pressure area are all minimum,and the pulse intensity of powder is the lowest,which is conducive to slowing down the elbow wearing. According to the results of numerical simulation analysis,combined with the actual production,the design optimization method was proposed to reduce the elbow wearing and to prolong the service life of the elbow.