Transient analysis of dust exposure under different supply airflow angle in a blasting tunnel based on CFD

Abstract

In recent years, with the rapid development of metro tunnels, many scholars have paid attention to the serious dust environment during blasting construction. To efficiently alleviate the dust pollution in working zone and reduce the ventilation time after blasting, this study adopted the CFD numerical simulation method to investigate the effect of supply airflow angle on the dust removal performance of 3 m breathing height within the working zone in an entrance and exit metro tunnel. The supply airflow angle corresponding to the optimal dust removal performance and minimum ventilation energy consumption was determined after in-depth analysis of four kinds of supply airflow angles. The simulation results showed that when the supply airflow angle was 30°, the minimum ventilation time was obtained in the breathing zone 5 m away from the driving face; while in the breathing zone 10 m, 15 m and 20 m away from the driving face, the minimum ventilation time was achieved when the supply airflow angle was 10°. From the view of the weighted average dust concentration and ventilation time in the working zone, the supply airflow angle of 10° could obtain the optimal dust removal performance and minimum ventilation energy consumption, with dust removal performance improved by 67.6% and ventilation energy consumption reduced by 20.46%.