吸粮机气力输送效率优化设计仿真

Optimization Design Simulation of Grain Machine Pneumatic Conveying Efficiency

在吸粮机输送效率优化中,针对输送颗粒在吸粮机输送管道处的堆积而导致的输送效率降低问题,提出一种输送管道结构优化方法。以垂直平面内的直角弯管为例,基于Fluent软件以RNG k—ε湍流模式完善的双欧拉模型对管道内的气固两相流作三维的数值仿真,并采用体积分数变化改进后的CDIPSA算法进行数值计算,研究在管径、料气比及入口气速一定的条件下,弯曲半径对颗粒相速度及管道中压力分布的影响。仿真结果表明,随着弯曲半径的增大,出口截面处颗粒相的速度分布先逐渐趋于均匀然后速度差明显增加,颗粒获得的最大速度值先升高后降低,同时弯管外侧壁面承受的最高压力值有所降低,承压面积逐渐减小。结果表明,当直角弯管弯曲半径为4倍管径时,吸粮机输送效率达到最高。

For the transmission efficiency degradation problem caused by the accumulation of particles at the grain machine bend,a bend structure optimization method was put forward. Taking the elbow bend pipe in the vertical plane for example,we used double- Euler model and the RNG k- ε turbulence model in Fluent to study the fluid field in 90° elbow for the three- dimensional numerical simulation,and then added the CDIPSA algorithm which considering the volume fraction changes to improve the numerical calculation. Uder the certain diameter,feed gas ratio,inlet velocity and the impact of bend radius on the material velocity and pressure drop were studied. Through the numerical analysis,it is found that with the increase of bend radius,the particle velocity distribution of the exit section gradually tends to be more uniform and then velocity difference obviously increases,the maximum velocity the particles obtained firstly rises and then reduces. At the same time,the highest pressure on the bend decreases,and the loaded area gradually decreases. The results show that when the bend radius is of about four times of the diameter,the grain machine can achieve the highest conveying efficiency.