小麦颗粒弯管流动特性数值模拟研究

Numerical Simulation of Flow Characteristics of Wheat Grain Bend

中文关键词: 小麦颗粒  气力输送  弯管  FLUENT  流动特性

英文关键词: wheat grain  pneumatic conveying  bend  FLUENT  flow characteristics

中文摘要:

      目的 为研究小麦颗粒在弯管处的气力输送的特性。方法 以欧拉-欧拉双流体模型为基础，结合壁面碰撞摩擦模型、颗粒动理学的固体应力和Gidaspow曳力模型构建出小麦颗粒在弯管处的气力输送模型，采用FLUENT对弯管处小麦颗粒气力输送过程进行数值模拟，分析小麦颗粒在流经弯管过程中及弯管后直管中的小麦颗粒密度分布、气固两相速度、小麦颗粒与壁面剪切力和颗粒相湍动能。结果 经过仿真分析和实验验证，小麦颗粒在流经弯管过程中，其颗粒相体积分数、气固两相速度、颗粒和壁面剪切力以及颗粒相湍动能4个方面随着流入弯管的角度变化而改变;由于颗粒-颗粒、颗粒-管壁之间的碰撞摩擦，小麦颗粒在流出弯管后随着输送距离的增大其各项参数逐渐减缓。结论 采用FLUENT软件进行仿真得到了弯管内小麦颗粒的流动特性，并通过实验验证了仿真的可靠性。此次研究结合气固两相理论，为弯管气力输送设计的研发和优化提供了理论基础。

英文摘要:

      The work aims to study the characteristics of pneumatic conveying of wheat grains at the bend. Based on the Euler-Euler two-fluid model, combined with the wall collision friction model, solid stress of particle dynamics and the Gidaspow drag model, a pneumatic conveying model of wheat grains at the bend was constructed. FLUENT was used to numerically simulate the pneumatic conveying process of wheat grains at the bend. The distribution of wheat grain concentration, gas-solid two-phase velocity, shear force between wheat grains and the wall and turbulent kinetic energy of wheat grains in the process of wheat grain flowing through the bend and the straight pipe after the bend were analyzed. The simulation and experimental results showed that the grain phase volume fraction, gas-solid two-phase velocity, grain and wall shear force and turbulent kinetic energy of wheat grains changed with the angle of flow into the bend. Due to the collision and friction among grains and between grains and the wall, the parameters of wheat grains gradually slowed down with the increase of conveying distance after flowing out of the bend. FLUENT software is used to simulate the flow characteristics of wheat grains in the bend, and the reliability of the simulation is verified by experiments. This study combines with the gas-solid two-phase theory and provides a theoretical basis for the design, development and optimization of pneumatic conveying in the bend.