为探究通风风速对分岔巷道内火灾烟气流动的影响，采用CFD数值模拟方法研究了火源位于主巷分岔口上游附近时，通风风速对烟气逆流长度、主巷下游和分巷内温度及CO质量浓度纵向分布的影响规律。研究结果表明：主巷内烟气逆流长度随着通风风速的增大呈现线性降低规律；不同通风风速下，呼吸带高度处分巷内平均温度略高于主巷下游，最大温差8 ℃；随着通风风速增大，主巷下游和分巷内呼吸带高度平均温度呈现出幂函数下降规律；随着通风风速的增大，呼吸带高度处主巷下游和分巷内CO质量浓度差值逐渐降低，最小质量浓度差为9.25 mg/m³，主巷下游和分巷内CO平均质量浓度均符合幂函数的下降趋势；当通风风速为1~3 m/s时，分巷道内工作人员不易受到火灾烟气有毒气体侵害，当通风风速为1.5~3 m/s时主巷下游内工作人员不易受到火灾烟气有毒气体侵害。

In order to investigate the influence of ventilation velocity on fire smoke distribution in bifurcated roadway, the computational fluid dynamics (CFD) numerical method was adopted to simulate the fires located in upstream of main-roadway. The influence of ventilation velocity on the length of smoke backflow and the temperature distribution and CO mass concentration distribution in main-roadway and sub-roadway were analyzed. The results showed that the length of smoke backflow decreased linearly as the increasing of ventilation velocity. The average temperature at the height of breathing zone in sub-roadway was little higher than that in main-roadway downstream under different ventilation velocity condition, and the biggest temperature difference is 8 ℃. The relationship between ventilation velocity and the average temperature at the height of breathing zone in main-roadway downstream and in sub-roadway fitted in power function trend. The CO mass concentration difference between main-roadway downstream and sub-roadway decreased gradually as the increasing of ventilation velocity, and the smallest mass concentration difference was 9.25 mg/m³. The relationship between ventilation velocity and the CO average mass concentration at the height of breathing zone in main-roadway downstream and in sub-roadway fitted in power function trend. When the ventilation velocity is 1-3 m/s, the workers in the sub-roadway are less susceptible to fire smoke and toxic gases, and when the ventilation velocity is 1.5-3 m/s, the workers in the main-roadway downstream are less susceptible to fire smoke and toxic gases