煤炭漏斗车煤堆上表面煤炭颗粒损失的数值仿真

Numerical Simulation of Coal Particles Loss Amount on Coal Pile Upper Surface of Coal Hopper Car

通过采用三维不可压缩方程和RNG k-ε双方程湍流模型,建立了一节煤炭漏斗车车厢三维模型,首次对其在时速80 km/h煤堆上表面的煤炭颗粒在气流影响下飘落损失的多相流流场进行数值分析.结果表明:煤炭漏斗车在运行过程中,车体前端墙为正压,侧墙及后端墙处于负压,在煤堆上表面前部有明显的涡流产生,在车体中部上表面区域空气流速较小,速度变化比较平稳;由于空气涡流的影响,煤堆上表面中部的煤炭颗粒先往前部堆积,导致煤堆中部的煤炭颗粒减少,随后,煤堆上表面的煤炭颗粒在气流的作用下大部分朝下游飘落损失掉了;煤炭颗粒粒径为0.5 mm的煤炭颗粒损失量为97.5%,粒径为5 mm的煤炭颗粒损失量为69%,粒径为1、3、5 mm的煤炭颗粒相比于0.5 mm的损失量分别下降1.5%、14.5%和28.5%,可以得出煤炭颗粒粒径与其损失量成反比关系,即粒径越大,损失量越少.

By using the three dimensional incompressible equation and RNG turbulence model,the three dimensional model of the coal hopper car is established,and the multiphase flow field of the coal particles falling loss on the upper surface of the coal piles is analyzed when it runs at a speed of80km/h on the opening line for the first time.The results show that the front wall of car body is in positive pressure,and side and back walls of the car body are in the negative pressure when the coal hopper car is running.Air vortex is produced in the front upper surface of the coal piles obviously.The air velocity is relatively small in the middle upper surface area of the coal piles,and velocity changes is relatively stable.Due to the effect of air vortex,coal particle is gathered in the front from the middle of coal piles,and the central particles is reduced,then most coal particles of the upper surface of the coal piles is downstream falling lost in the air flow under the action.Loss amount of0.5mm of particle diameter is97.5%,loss quantity of5mm of particle diameter is69%,loss amount of1mm,3mm and5mm of particle diameter are respectively reduced by1.5%,14.5%and28.5%compared to0.5mm.