U形弯管内大颗粒固液两相流的输送特性研究

应用计算流体力学及离散元耦合计算方法,对U形弯管中大颗粒固液两相流的输送特性进行了研究。采用Fluent与EDEM耦合计算,对不同输送工况下U形管中的大颗粒输送进行了仿真分析,得到了颗粒及流场在U形弯管中的分布、运动特性,同时结合试验进行了验证分析。结果表明,颗粒进入U形管后由于惯性作用主要沿着管道壁面运动。低速输送工况下,颗粒容易堆积在U形管与提升管的过渡位置,随着输送速度提高,颗粒在U形管中的浓度降低。由于与管道壁面的碰撞、摩擦,颗粒开始沿着壁面滚动运动。弯管内的二次流也会对颗粒的运动和分布产生一定影响。

Transport Characteristics of Large Particles in U-shaped Pipe

The transport characteristics of solid-liquid two-phase flow with large particles through a U-shaped pipe were studied by coupling computational fluid dynamics (CFD) and discrete element method (DEM). The transportation of larger particles through a U-shaped pipe under different conveying conditions was simulated using Fluent coupled with EDEM. As a result, the distribution and motion characteristics of the particles and flow field in the U-shaped pipe were obtained, which were then verified by the experiments. It is found that particles, once entering the U-shaped pipe, mainly move along the pipe wall due to the action of inertia. With the low conveying speed, the particles tend to be accumulated in the transition area between the elbow and the raising pipe. As the conveying speed increases, the concentration of the particles in the U-shaped pipe decreases. Due to the collision and friction with the pipe wall, the particles begin to move along the pipe wall by rolling. Furthermore, the secondary flow in the bend also brings a certain impact to the movement and distribution of the particles.