# Numerical Simulation of Co-Barrier Efficiency of Air Curtains in Mine Refuge Chambers
###### Abstract  
Toxic and harmful gases may follow evacueues into the mine refuge chamber, endangering their life during the mine disaster. Gases from the outside environment are successfully kept out of the mine refuge chamber by air curtains. The effect of the air curtain installation position, jet velocity, angle, and structural parameters on the CO barrier efficiency is studied using numerical simulation of computational fluid dynamics (CFD) in this paper. The results are also used to show the influence of the above factors on the efficiency of the air curtain. The results show that: (1) increasing the air curtain jet speed does not always increase or even decrease the air curtain barrier efficiency. (2) The best CO barrier efficiency of 68.1% was obtained by an air curtain installed on the top side of the refuge door with a velocity of 22 m/s and a jet angle of 10\({}^{\circ}\). (3) A mathematical relationship between air curtain structural parameters and barrier efficiency is developed to provide a reference for the design of air curtain pipeline structures. air curtain; mine refuge chamber; barrier efficiency; structural parameters; mathematical relationship +
Footnote †: journal: _aciences_  
0000-0002-4899-2233-2333-2333-2333-2333-2333-2333-2333-2333-23333-2333-23333-2333-23  
used widely to study air curtains because of its high accuracy, easy operation, and low cost [18; 19]. [PERSON] and [PERSON] [20] found by bench experiments and FLUENT that air curtains can effectively barricade heat and smoke in fires and suggest using CFD software to study the design of air curtains in fire safety engineering. [PERSON] et al. [21] used a numerical study to find that air curtains can effectively confine smoke and CO gases released from fires in the near-fire area. [PERSON] et al. [22] found that air curtains affect wind fields, dust distribution, and particle number within about 15 m of an underground mining operation in the coal mine. These studies show that air curtains can provide a gas barrier effectively confine the flow of CO gases. Analysis of the air curtain is crucial to finding the design parameters and suitable conditions for the air curtain to barrier the toxic and hazardous gases [23]. [PERSON] et al. [24] found by CFD numerical simulation and experimental study that the highest sealing efficiency is obtained by installing a double-side air curtain device at the protective door of the refuge. [PERSON] et al. [25] studied the smoke suppression effect of the opposed double-jet curtain in high-rise building fires and found that the smoke and CO released during the fire were confined in the corridor. [PERSON] et al. [26] found that horizontal air curtains can effectively control the CO gas flow in building fires. [PERSON] et al. [27] found that the width of the air curtain nozzle has a limited influence on the sealing effect. When the angle of the air curtain spraying to the fire source is 30\({}^{\circ}\), the air curtain has the best effect in blocking smoke. [PERSON] et al. [28] found that the effectiveness of preventing smoke is stronger the higher the jet velocity and the wider the air curtain. The effectiveness of controlling smoke gradually decreases as the jet angle increases. [PERSON] et al. [29] studied the efficiency of the emergency ventilation system and discovered that by altering air curtain parameters and the emergency ventilation system, the diffusion of heat, CO, and CO\({}_{2}\) could be controlled for various fire sites and heat release rates. [PERSON] et al. [30] used CFD simulation software to study the variation of CO concentration, visibility, and temperature at different air curtain jet velocities in the same fire environment and found that when the jet velocity of the air curtain is 14 m/s, it is the most effective in restricting the smoke flow. It can be seen from the above analysis that the nozzle width, speed, installation position, and airflow angle of the air curtain have a significant influence on the blocking efficiency of the air curtain.