一种新型三区段喷雾系统及降尘性能研究

为解决隧道爆破粉尘排除难和粉尘质量浓度超标的问题，设计了新型三区段喷雾系统并对其相关参数开展研究。基于自行搭建的喷雾降尘试验平台，分析隧道爆破粉尘样本粒径特征与喷嘴适用性； 利用CFD软件对喷嘴不同布置方式与入射角度进行数值模拟，分析雾滴场中质量浓度、速度和粒径等特征的变化规律； 通过现场应用测试新型喷雾系统降尘性能。研究结果表明： 1）隧道沿程粉尘峰值体积频率向小粒径方向移动，且峰值体积频率不断增大； 2）直径1.9 mm的广角型实心锥形喷嘴对近掌子面处的粉尘抑尘效果更佳，1.2 mm的精细型实心锥形喷嘴适用于小粒径粉尘除尘； 3）随着入射角度的增加，雾滴直接入射区域内质量浓度超过1 g/m3的面积先增加后减小； 4）喷嘴置于顶部、侧部和底部时，最佳入射角度分别为60°、60°和45°。现场应用表明，采用三区段喷雾系统后，各测点位置呼吸尘和全尘降尘效率均高于75％，与原有控尘措施相比，平均降尘效率提高了42.71％，能有效改善洞内施工人员作业环境和阻止隧道内粉尘向外扩散。

Novel Three Section Spray System and Its Dustproof Performance

Blasting construction in tunnels always induces overstandard dust concentration and difficulty in dust removal. Therefore, in this study, a new three section spray system is designed, and its relevant parameters are studied. Based on a self built spray dust experimental platform, the particle size characteristics and nozzle applicability of the dust samples at the tunnel blasting site are analyzed. Moreover, a computational fluid dynamics software is used to simulate different nozzle layout schemes and incident angles, and the variation laws of concentration, velocity, and particle size in the droplet field are analyzed. Furthermore, the dust removal performance of the new spray system is tested through a field application. The obtained results are as follows: (1) The peak volume frequency of dust along the tunnel moves toward the direction of particle size reduction, and the peak volume frequency increases continuously. (2) The wide angle solid conical nozzle with a 1.9 mm diameter has better dust suppression effect on the dust near the face, and the fine solid conical nozzle with a 1.2 mm diameter has better dust suppression effect on small particle size dust. (3) As the incident angle increase, the area with dust concentrations exceeding 1 g/m3 in the direct incident area of droplets first increases and then decreases. (4) When the nozzle is placed at the top, side, and bottom, the optimal incident angles are 60°, 60°, and 45°, respectively. The field application shows that the dust removal rates of respiration dust and all dusts at each measuring point all exceed 75%. Compared with the original dust control measures, the average dust removal rate of the three section spray system is increased by 42.71% and can effectively improve the working environment of the construction personnel in the tunnel and prevent outward diffusion of dust in the tunnel.