Multi-factor influence of cross-sectional airflow distribution in roadway with rough roof

Abstract

The wall surface roughness renders a significant impact on ventilation of roadways and cross-sectional wind speed distribution. Herein, the wall roughness (R_a) in the roadway has been defined theoretically. Moreover, three-center arched roadway models for different situations are established based on the normal distribution of roof roughness. The influence of inlet velocity, roof roughness and roadway height on wind speed distribution is systematically studied by using Fluent software. At R_a=0.1 m, the simulation results reveal that the wind speed is negatively related to the distance from the wall to the point where 80% of the central wind speed is reached (D_A). Also, the wind speed distribution is significantly influenced by increasing the roof roughness. However, the wind speed distribution becomes asymmetric at R_a=0.2 m and 0.3 m. Furthermore, the low-speed area (v≤1 m/s) started to concentrate on the roof with the increase of roadway height. Overall, an R_a value of <0.1 m can reduce the influence of wall roughness on wind speed distribution of the roadway, which is suggested in practical applications.

Keywords

roughness model / roadway section / airflow distribution / numerical simulation / mine ventilation

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