摘要
为了确定大断面掘进工作面压入式风筒的最佳安设高度,采用数值模拟方法分别模拟了风筒中心距底板6 m、4.5 m、3 m、2 m以及风筒安设于洞室顶部时,通风20 min后爆破炮烟(CO)的稀释效果,并求解了各种风筒布置情况下不同断面的通风死区比例。结果表明,通风排烟效果最差的情况为风筒固定于侧帮距底板6 m时,其次为风筒固定于侧帮距底板4.5 m时,再次为风筒固定于顶部中央时,风筒固定于侧帮距底板2 m时CO在巷道内的呼吸带高度沿程浓度分布与风筒距底板3 m时差别不大,但风筒中心距底板2 m时容易造成掘进工作面上隅角炮烟和粉尘的积聚。因此,大断面掘进工作面压入风筒最佳安设高度为3 m。
The paper is inclined to come up with a numerical simula- tion for the optimal driving duct height in a large cross-section driving face via a commercial code named Fluent. For this purpose, we would like to illustrate the dilution effects of the toxic gas （especially CO ） produced by the mining blast after 20 rain when the forcing ducts were supposed to be on 6 m, 4.5 m, 3 m, 2 m high from the floor and at the top of the cross-section, respectively. In doing so, it is also necessary to work out the percentage of the dead zones （PDZ） at different planes for convenience to compare the ventilation effects of all the different systems. The results of our simulation show that the optimal condition the ventilation system with the forcing duct would like to offer should be chosen at a point of 3 m high from the floor in the system with the duct located at the top of the cross-section. How- ever, the system with the duct set at the height of 4.5 m can be ex- pected to provide a better ventilation effect whereas that of the 6 m high tends to give out the worst effect. Although CO density and PDZ at the breathing-zone height along with the tunnel strike may vary lit- tle when the duct is located at the 3 m and 2 m high from the floor, the latter tends to cause an accumulation of toxic gas and dust at the upper comer of the driving face. In addition, we have also investigat- ed the velocity of the central plane of duct in a range of 20 m from the driving face and provide an analysis of the structure of the flow force distribution. In addition, we have split the velocity field into three sections： the jet flow section, the eddy section and the recirculation one. Whereas the second section shrinks as the duct height lowers, and then disappears when the duct is located at 2 m high from the floor, the third section tums to occupy the small area in the ventila- tion system with the duct heights coming to 6 m and 4.5 m. Since the eddy section aggravates the accumulation of the poisonous gas and dust, and the recirculation section tends to facilitate their dilution, the optimal height of the forcing duct in this case should be set at 3 m high from the floor. It is at this height that can most probably be in nice agreement with the empirical data obtained from the construction site, which can thus validate the simulation results.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第1期25-28,共4页
Journal of Safety and Environment
关键词
安全工程
掘进通风
大断面
压入式风筒
数值模拟
通风死区比例
safety engineering
driving face ventilation
large cross-section
forcing duct
numerical simulation
percentageof dead zones
