掘进机外气动涡旋雾幕控尘装置的研制与实验

为有效控制由掘进机截割头旋转破碎引发的粉尘污染,基于高压喷雾在涡旋气体射流场中的运动规律及二次雾化破碎特性,研制了一种可以阻隔工作区域高质量浓度粉尘迁移扩散的新型掘进机外气动涡旋雾幕控尘装置。绘制了包含掘进系统的气动涡旋雾幕控尘装置的比例模型,并通过利用CFD数值模拟软件获得该型设备外部风流场迁移规律和液滴粒子运动规律,以模拟结果为理论基础建立实验平台,并对设备的雾化性能及控尘性能进行了实验测定。模拟结果表明:在环状风筒前端形成了完整旋转风幕,外环高压喷雾受内环高速旋转风流冲击,加剧了液滴的破碎、迁移扩散与捕尘性能。雾化性能实验结果表明:该型设备雾化性能主要由气体射流与高压喷雾的相间速度差决定,喷雾夹角为45°～75°,相间速度差较大,气相射流风速对雾化性能影响占主导地位;喷雾夹角大于75°时,相间干涉减小,喷雾压力占主导地位;随着沿流向方向的距离增大,风速快速衰减,液滴运动趋于稳定。控尘性能实验研究结果表明:当喷雾压力、喷雾夹角不变的情况下,单独提高引射射流风速时,涡旋雾幕前方粉尘捕集较差,全尘和呼尘平均捕集率分别为21.21%和26.24%;而雾幕后方,不同风速下的全尘捕集率分别为84.98%,87.88%和90.70%,呼吸性粉尘捕集率为83.89%,87.87%和88.71%,照比传统高压喷雾表现出更好的控尘性能。

Research and experiment on dust control device with external pneumatic vortex mist curtain for road header

To effectively control the dust pollution caused by the road header cutting head rotary breaking,based on the motion law of the high pressure spray in the vortex gas jet and the secondary atomization fragmentation characteristics,a new type of dust control device with external vortex air mist screen for road header has been developed,which can prevent high concentration dust dispersion in underground mining area.A scale model of a pneumatic vortex mist curtain dust control device including a tunneling system was drawn.Through the numerical simulations,the wind flow field migration law and droplet particle motion law of the device were obtained by using CFD software.An experimental platform was established based on the simulation results,and the atomization performance and dust control performance were obtained by experiment.The simulation results show that a complete rotating air curtain was formed at the front of the ring mounted air duct.The outer high pressure spray was impacted by the high speed vortex rotating airflow,which aggravated the droplet breakage,diffusion and dust collecting performance of the spray field.The atomization performance experiment results show that the main performance of the mist curtain is determined by the velocity difference between the gas jet and the high pressure spray.When the spray angle is between 45°-75°,the velocity difference between phases is great,and influence of gas jet velocity on atomization performance is dominant.When the spray angle is greater than 75°,the interphase interference decreases and the spray pressure dominates.With the increase of the distance along the direction of flow,the fast attenuation of wind speed leads to the stabilization of droplet motion.The dust collecting performance experimental results shows that when the spray pressure and the spray angle are constant,when raising the jet velocity alone,the dust collection in front of the vortex mist curtain is poor,and the average dust collecting rates of dust and respiratory dust are 21.21% and 26.24% respectively.At rear of the mist screen,the dust collection rates at different wind speeds are 84.98%,87.88%,and 90.70% respectively.The respiratory dust collection rates are 83.89%,87.87%,and 88.71% respectively,which shows a better dust control performance than that of traditional high pressure spray.