Intelligent safety adjustment of branch airflow volume during ventilation-on-demand changes in coal mines

In view of the frequent ventilation-on-demand (VOD) changes of branches during intensive production in coal mines, the models for regulating the ventilation resistance of associated branches and ventilator frequency were established. Automated ventilation system adjustment software has been developed by monitoring the air volume of the minimum remainder branch in the network, and all air volumes of the branches in the network can be obtained by inverse calculation of associated branches. When the VOD of branches changes, the best regulating branch in the ventilation network is selected by a cellular automation (CA) model, and the ventilation resistance is determined by ventilation network calculation. It is also possible to calculate the total air volume of the ventilation system, according the VOD of the branch to calculate the ventilator frequency. Advanced simulation regulating results are verified by ventilation network calculation. The ventilation resistance of associated branches, ventilator frequency, and joint regulation are simulated by the automated ventilation system adjustment software. A pipe network ventilation parameter monitoring system is designed and developed based on typical ventilation network models. We confirm the VOD of the branch based on the absolute gas emission volume prediction model and then establish a regulating model for the ventilation resistance of associated branches and the ventilator frequency. Considering the fire and explosion risks associated with gas, CO2 is instead released to simulate gas emission in the experiment; gas concentration is controlled by the ventilation resistance of associated branches and ventilator frequency. These results verify that CO2 concentration is kept below the threshold value by increasing the air volume of the branch, the feasibility of the ventilation system, and regulating the VOD of the branch; additionally, they provide theoretical guidance for adjusting ventilation branch quantity by the association branches of ventilation resistance and ventilator frequency.