气力输送弯管结构替代装置流场特性数值分析

Numerical Analysis of Flow Field Characteristics of a Device in Replacement of Pipe Bend in Pneumatic Conveying System

气力输送弯管转向过程中磨损和固相滞留等问题较为严重。本研究设计了一种新型连接装置,对结构进行了优化设计以减少磨损,用扩容仓代替弯管,在底部增加增压风,并利用计算流体动力学(CFD)数值方法,采用k-?标准型湍流模型,分析进出口中心线上速度比(V_a/V_0)和总压变化,及两相流颗粒分布,模拟结果表明,采用新型输送装置,将主流转向提前至垂直管道下方,利用风膜隔开主流与壁面,减少了磨损和固体颗粒滞留;增压风和主流风速比3.4时,出口速度差值最小,形成的额外阻力最小,该比例下增压风综合效果最好。

The problems such as abrasion and retention of solid phase during the bending process of pneumatic conveying pipe appear to be more serious. In this study, a new type of connecting device was designed to optimize the structure to reduce the wear and tear. Instead of bending, expansion bank was used at the bottom to increase the pressurized air. The velocity ratio（Va/V0） at the center line of the inlet and outlet, the total pressure change and the particle size distribution of the two-phase flow were analyzed by using the computational fluid dynamics（CFD） numerical method and k-ε standard turbulence model. The simulation results show that the main flow is turned in advanced to the bottom of the vertical pipe by the new conveying device, and the wind and membrane are separated from the wall to reduce the wear and the solid particles. When the ratio of the supercharged air and mainstream wind speed is 3.4, the difference of outlet velocity and the additional resistance is the least, hence bringing the best combined effect.