垂直螺旋输送机临界转速的仿真研究

Simulation research of critical speed for vertical screw conveyor

为确定实际模型的临界转速,采用EDEM、RecurDyn和ADAMS.2建立螺旋直径为400 mm、升程为330 mm的双螺旋垂直螺旋输送机和单个颗粒的仿真模型;通过仿真确定临界转速的区间,根据二分法不断缩小临界转速的区间,直至得到临界转速终止仿真;在EDEM中建立输送高度为0.3 m、填充率分别为20%、40%、60%和80%的颗粒群仿真模型,采用相同的方法完成仿真。结果表明:仿真结果验证了粒子与螺旋面、罩壳内壁之间的接触力类型,得到单个颗粒时螺旋的临界转速约为70 r/min;4种填充率下的临界转速分别为75、81、91、100 r/min;单质点法求解的理论临界转速为82 r/min,与单个颗粒、输送高度为0.3 m、填充率为20%和40%的颗粒群仿真结果接近,而小于输送高度为0.3 m、填充率为60%和80%的颗粒群仿真临界转速。说明单质点理论只适用于小填充率的垂直螺旋输送机模型。

In order to determine the critical speed of the actual model, a simulation model, including a single particle and a double spiral vertical screw conveyor was presented, whose screw diameter was 400 mm and pitch was 330 mm. The simulation model was established by EDEM, Recur Dyn and ADAMS.2.First, the range of critical speed was obtained through simulation.Then, using the bisection method, the range was narrowed gradually. Finally, the simulation was terminated until the critical speed was obtained. The simulation model of particle swarm were established and simulated based the same method by EDEM,whose height was 0.3 m and filling rates were 20%, 40%, 60%and 80%. The results show that the types of contact between particle and spiral surfaces and inner surface of the shell are verified. The critical speed is about 70 r/min when there is only one particle. The critical speed for four filling rates are 75, 81, 91 and 100 r/min. The critical speed which is obtained by single particle theory is 82 r/min, and the value is close to the simulation results of one particle and particle swarm with 20% and 40%filling rates. But the value is smaller than the results of particle swarm with 60% and 80% filling rates. So single particle theory is only applied to the vertical screw conveyor with small filling rate.