采场爆破粉尘运移规律的Fluent数值模拟

Numerical simulations of blasting dust migration with the use of Fluent in stope

在对爆破烟尘源及其特征分析的基础上,以西石门铁矿南二采区为研究背景,运用Fluent软件通过气固两相流数值模拟方法对爆破后粉尘的分布及扩散规律进行研究,得出在现有条件下爆破粉尘的运移规律。采场爆破后很快产生大量粉尘且浓度较高,粉尘的运移受风流流场影响较为明显。在现有通风条件下,粉尘的净化主要靠重力沉降,而难以沉降的呼吸性粉尘的排出则需要较长时间。这不利于生产,亟须改善通风条件或采取其他措施较快速降低爆破粉尘浓度。数值模拟结果与现场测量结果基本一致,爆破产尘量大,排尘耗时久。

The paper is aimed at introducing our numerical simula- tions of the gas-solid two-phase flow in the use of fluent software so as to trace the migration regularity of blasting dust under current condi- tions. The whole study of ours has been done by taking the Southern Mining Area 2 of Xishimen Iron ore as our case study. As the result, we have found that a great deal of dust has been produced at a con- centration as high as to 3.45 ~ 10-2 kg/m3 immediately after the stope blasting. At the same time, we have found that the air flow field plays a major role in the migration of blast dust with a higher dust concentration gathering in the comer than elsewhere. Under ex- isting ventilation conditions, the air flow tends to have a lower veloci- ty of 0.4 meter per second in a juncture with the working face in the stope as a heading face, so that the dust may not be mainly decon- taminated by the gravity settlement. And, therefore, the respirable dust which is likely to suspend long in the air can be removed circu- larly under the action of air flow field and needs a long time to get it eliminated, which may not be conducive to safe production, nor to accident elimitation. Therefore, it is thus imperative to improve the ventilation conditions and take other safety-ensuring measures to lower the blast-dust concentration more efficiently. The simulation results prove to be in accord with the field measurement results--large amount of blasting dust and a long lasting discharge, which are likely to account for the reliability of the numerical simulation. In addition, the simulation results can also serve as a theoretical basis for success- ful application of the effective, rational and suitable dust control tech- nology, so as to reduce and control the dust concentration in the stope.