关键词: 空气幕, 射流角度, 隔断压差, 阻风率, 流场分析, 数值模拟

Abstract:

Most of the metal mines in China are combined vertical shafts and ramp roads.Under the joint action of multiple factors such as long-term ground pressure and frequent traveling，the dampers are severely damaged and extremely inconvenient to manage and maintain.In the context of intelligent ventilation development，the traditional manual or semi-manual airflow control measures can hardly meet the requirements of intelligent ventilation in mines，and the control of airflow can’t be realized or can’t achieve the expected effect in the special conditions of the tunnel.Mining air curtain is a new type of airflow control technology that can achieve intelligent control of airflow in more complicated conditions in the tunnel without affecting the transportation of equipment and the work of personnel in the tunnel.To investigate the effect of twin parallel air curtains in a non-coal tunnel to intercept the wind flow，a metal mine project tunnel in Gansu Province was taking as the background，based on Fluent numerical simulation technology，the K45-6 axial flow fan was selected，by changing the fan full pressure and jet angle to establish different mathematical and physical models of the original tunnel，the flow field inside the original tunnel for numerical simulation，according to the simulation results of the twin parallel air curtains on the tunnel flow field，the impact analysis was carried out based on the simulation results.The analysis was carried out in three aspects，namely differential pressure，air leakage，and air blockage rate.The main conclusions of this study include：（1）When the full pressure of the fan is a constant value，as the air curtain jet angle increases，the differential pressure and wind resistance show a trend of first increasing and then decreasing，and the differential pressure and wind resistance increase significantly when the jet angle is 5°~30°，the differential pressure and wind resistance increase significantly，and the air curtain gradually converges into a complete air curtain.When the jet angle reaches 30°，the differential pressure and wind resistance reach the maximum value，and the most complete air curtain is formed.But the rising trend in 15°~30° is flatter than 5°~15°.When the jet angle continues to increase to 45°，the differential pressure and wind resistance rate drop significantly.When the jet angle continues to increase to 60°，the differential pressure and wind resistance rate are the lowest.As the jet angle continues to increase，the lateral pressure from the tunnel can’t effectively block the wind flow.（2）The air leakage volume shows a trend of decreasing and then increasing as the jet angle increases，and the air leakage volume decreases more obviously when the jet angle increases from 5° to 15°.When the jet angle increases to 60°，the isolation capacity is the worst.（3）When the jet angle is too small or fans’ full pressure is too large，the phenomenon of induced airflow will occur，then the double machine parallel circulation type air curtain will be downstream of the tunnel air to the upstream，no longer can it intercept the tunnel wind flow.According to comprehensive analysis，obvious effect of air control can be obtained by setting double parallel circulating air curtain in the roadway，and the optimal parameter combination of double machine parallels circulation-type air curtain is that the fan full pressure blade angle is 30° at the same time jet angle is 30°.

Key words: air curtain, jet angle, partition pressure difference, wind resistance, flow field analysis, numerical simulation