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

顶板不平整巷道断面风速分布的多因素影响

The wall surface roughness renders a significant impact on ventilation of roadways and cross-sectional wind speed distribution.Herein,the wall roughness(Ra)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 Ra=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(DA).Also,the wind speed distribution is significantly influenced by increasing the roof roughness.However,the wind speed distribution becomes asymmetric at Ra=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 Ra 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.

表面粗糙度对于巷道通风及断面风速分布产生重大影响。本文从理论上定义了巷道中的壁面粗糙度(Ra),并基于顶板粗糙度的正态分布,建立了不同情况下的三心拱巷道模型,利用Fluent软件系统地研究了进口风速、顶板粗糙度和巷道高度对风速分布的影响。模拟结果表明,在Ra=0.1 m时,风速与从壁面到中心风速达到80%的点的距离(DA)负相关,且风速分布受到顶板粗糙度增大的影响明显,而风速分布在Ra=0.2和0.3 m时变得不对称。此外,随着巷道高度的增加,低速区域(v≤1 m/s)开始集中在顶板附近。总体而言,Ra值小于0.1 m可以减少顶板粗糙度对巷道断面风速分布的影响,建议在实际应用中使用。