Dynamic calculation of heat-flow coupled mine ventilation network with introduction of air volume fluctuation factor

To address the issue of continuous multi-scale fluctuations in air volume due to the thermal flow within the unsteady airflow medium in the ventilation system pipe domain, which limits the accuracy of system state mapping when using a static thermal-pressure-humidity ventilation calculation model. Under the framework that the air flow is a polytropic process involving coupled aerodynamic and thermodynamic processes, the real-time and accurate mapping of the system operation state is equivalent to dynamically calculation the heat-flow coupling fluctuation mine ventilation network under time series. The underlying multiscale fluctuation principles of heat-flow coupled air volume were examined, identifying airflow density as the primary cause of volume fluctuation. Using this as a characterization variable, with unsteady environmental and gradient flow fields as boundary conditions, an infinitesimal approach was used to analyze the time-variant law of heat-flow coupled property of airflow. A transient airflow feature model was developed with time as the root variable. An air volume fluctuation factor was defined to capture the transient position of fluctuating air volume, which was then incorporated into a static ventilation network model, yielding a fluctuating ventilation network calculation model with continuous spatial characteristics. Additionally, a transformation equation linking the fluctuation factor with the transient airflow feature model was established to integrate the transient flow function as a fluctuation transfer variable in the fluctuating ventilation network model, thereby forming a time-series-based dynamic calculation model for the fluctuating ventilation network to achieve real-time, precise mapping of the network state. To validate the production feasibility of the dynamic calculation model for the fluctuating ventilation network, Shuangma I Mine was taken as the engineering case, with cross-strata thermal environment data in time series applied as the initial condition. This enabled real-time global ventilation network calculation, expanding the fixed initial air volume value into a time-series fluctuation range and accurately reflecting the real-time operational characteristics of the production ventilation system under the heat-flow coupled airflow condition. The dynamic calculation for the fluctuating ventilation network facilitates precise quantitative mapping of the ventilation network state through real-time analysis of the coupling effect between the mine environment and ventilation variables, establishing a data foundation and optimized pathway for subsequent intelligent quantitative decision-making to enhance the adaptive adaptability and intrinsic precision of intelligent ventilation control.