Prediction of airflow temperature in underground long-distance excavation roadway and ventilation duct: Numerical simulation and field test validation

Abstract

High geothermal conditions in deep mineral excavation pose significant heat hazards, limiting safe and efficient resource extraction. In this work, we numerically established a comprehensive mathematical model to predict the airflow temperature in underground long-distance excavation roadway and ventilation duct. Our model was then solved using a self-developed numerical simulator based on the finite volume method (FVM) and finite difference method (FDM). Finally, the simulation results were validated by field measured data and the effect of key parameters on airflow temperature was discussed. The results show that (i) The simulation results are consistent with the measured data within a maximum error rate of 2 %, indicating that the developed model and simulator can accurately predict the thermal environment of long-distance excavation roadway. (ii)The heat release from electromechanical equipment and surrounding rock accounts for more than 90 % of the total heat load, which is the decisive factor leading to high-temperature heat hazards. (iii) The airflow temperature in the roadway is proportional to the original rock temperature, and the thermal environment will deteriorate rapidly with the increase of mining depth. (iv) For every 1000 m increase in roadway excavation length, the airflow temperature at the heading face will rise by 0.88℃. (v) As the average excavation speed increases, the airflow temperature in the roadway increases in a parabolic trend. (vi) Increasing the inlet airflow volume and cooling the inlet airflow can effectively improve the overall thermal environment in the roadway. This research provides theoretical support for controlling the high-temperature heat hazard in roadway excavation.