煤矿锚喷作业区喷浆粉尘数值模拟与新型湿喷一体机研制

Numerical simulation on gunite dust of bolt-shotcrete operating area in coal mine and development of new wet spraying integral machine

基于颗粒离散相模型采用FLUENT软件分别对干、湿喷时的喷浆粉尘运移规律和质量浓度进行数值模拟。根据呼吸带高度粉尘质量浓度模拟结果,提出"湿喷粉尘预防三区"的概念。研究结果表明:湿喷物料反弹射流较干喷对风流径向偏移的影响显著,加之湿喷粉尘粒径较大,所以其扩散较为均匀,沉降速度较快,整个巷道空间内的湿喷粉尘质量浓度比干喷时大为降低。在湿喷口后方16 m以外为最佳作业区域。为降低喷浆作业现场的粉尘质量浓度,改变目前湿喷机、搅拌机单独成体,运动、应用不方便的弊端,根据液压驱动原理研发集搅拌、喷射、行走三功能合一的湿喷一体机。相对于干喷而言,采用一体机湿喷作业后,作业现场的全尘、呼尘质量浓度和混凝土物料的回弹率大幅降低,并且提高了喷射混凝土大板的28 d抗压强度。

The numerical simulations on gunite dust of migration law and mass concentration during dry and wet spraying were conducted by FLUENT software based on dispersed phase model. According to the simulation results of dust mass concentration in the area of respiratory zone＇s height, the concept of ＂preventive three zones of wet spraying dust＂ was proposed. The results show that the wet spraying materials＇ rebound jet has much more influences on the air＇s radial offset compared with that of dry spraying. Moreover, the dust particle size of wet spraying is large, so it has even diffusion and high settling velocity. The wet spraying dust concentration in the whole roadway is much smaller than that during dry spraying. The best operating area should be more than 16 m behind the wet spray gun. In order to decrease the dust concentration in the process of shotcrete and avoid the shortcomings i.e. wet spraying machine and mixer work as two separate bodies and their applications and movements are not convenient, the integral wet spraying machine with the functions of stirring, spraying and moving are designed according to the hydraulic driving principle. Compared with dry shotcrete, after applying the integral wet spraying machine, the mass concentration of whole and respirable dust and the rebound ratio of concrete materials in the working areas sharply decreases, moreover, and the compressive strength for the spraying concrete board of 28 d increases.