As one of the effective way of smoke exhausting method, the lateral mechanical exhaust system is gradually being adopted in more and more scenarios. While compared to the numerous investigations on the ceiling exhaust system, the of influence of plug-holing and the key factors that affect the smoke exhaust effect of lateral system are quite insufficient. During the smoke exhaust process, the plug-holing phenomenon will cause the fresh air to be drawn directly into the exhaust vent, and thus weakening the smoke exhaust effect. To reveal the key factors that influencing the smoke exhaust effect and the plug-holing phenomenon, a set of numerical simulations were conducted in a subway station with the lateral mechanical exhaust. Results show that with the increase of exhaust velocity, the phenomenon of plug-holing will occur at the lateral exhaust vent. The occurrence of plug-holing can lead to the decrease of the exhausted smoke concentration. Furthermore, by introducing a virtual smoke vent that perpendicular to the original lateral one, a critical Froude number for predicting the occurrence of plug-holing of lateral mechanical exhausting is proposed. Based on the results of different exhaust velocities, heat release rates and smoke vent heights, the critical Froude number that corresponds to the occurrence of the plug-holing can be determined as 0.5 for the lateral mechanical exhaust.

作为排烟方法的一种有效方法，侧向机械排烟系统正越来越多地被采用。与对天花板排气系统的大量研究相比，塞孔的影响和影响侧向系统烟气排放的关键因素还远远不够。在排烟过程中，塞孔现象会导致新鲜空气被直接吸入排烟口，从而削弱了排烟效果。为了揭示影响排烟效果和塞孔现象的关键因素，在地铁车站进行了侧向机械排气的一组数值模拟。结果表明，随着排气速度的增加，堵塞排气的现象将发生在侧面排气口。塞孔的发生可导致排出的烟气浓度降低。此外，通过引入垂直于原始横向排气孔的虚拟排气孔，提出了用于预测横向机械排气塞孔发生的临界弗洛德数。基于不同的排气速度，放热率和排烟高度的结果，对于侧向机械排气，与塞孔的发生相对应的弗洛德临界值可以确定为0.5。提出了用于预测侧向机械排气塞孔发生的临界弗洛德数。基于不同的排气速度，放热率和排烟高度的结果，对于侧向机械排气，与塞孔的发生相对应的弗洛德临界值可以确定为0.5。提出了用于预测侧向机械排气塞孔发生的临界弗洛德数。基于不同的排气速度，放热率和排烟高度的结果，对于侧向机械排气，与塞孔的发生相对应的弗洛德临界值可以确定为0.5。