Air quality control in mine refuge chamber with ventilation through pressure air pipeline

•A study combined experiment and numerical analysis was firstly performed to improve the ventilation system in a Mine refuge chamber (MRC).•A new analytical model of fifty-person MRC is proposed.•Average CO2 concentration can be controlled below 0.5 % by ventilation of 0.1m3/min per person.•Air inlets arranged on both sides or top and air outflows arranged on both ends of the MRC are recommended.•A quantitative relationship between CO2 concentration and ventilation rate, CO2 release rate was proposed. A combined experimental and numerical study was performed to improve the performance of the ventilation system in a mine refuge chamber (MRC). In the experiment, CO2 cylinders and dispersion pipes were used to simulate the CO2 release of 50 people, and 0.1L/min per person of fresh air was provided by an air compressor. A new analytical model for a 50-person MRC was proposed and validated against the experimental data. Sensitivity analysis was carried out to investigate the effects of several control factors. The results indicated the following: (1) The ventilation system layout has a significant influence on the CO2 concentration distribution in an MRC, while the uniformity of the CO2 concentration distribution in the MRC may not be effective with increased number of air inlets. (2) Under a well-arranged ventilation system in the 50-person MRC, the average CO2 concentration can be controlled at less than 0.5 % with a ventilation rate of 0.1m3/min per person, and less than 0.2 % with a ventilation rate of 0.3m3/min per person. (3) A quantitative correlation exists between the CO2 concentration and ventilation volume rate, as well as the CO2 release rate, for an MRC under a well-arranged ventilation system.