Review of numerical studies on ventilation systems for subway networks in emergency situations

Since the subway systems are constantly developing at a high rate to cope with the increasing number of commuters, their safety is a great challenge and extensive research was done to fulfil the safety regulations in this field. Numerical modelling represents a modern research method used more frequently in the academic environment over the last decades, being constantly validated through comparisons with results of other classical research methods. This paper presents a thorough analysis of the numerical studies on smoke evacuation in emergency situations from tunnels and subway stations, with a focus on the research concerning the use of platform screen doors (PSD) in emergency situations generated by fires. The numerical simulation software mostly used are Fire Dynamics Simulation and Ansys Fluent (based on Computational Fluid Dynamics modelling technique), their results being extensively compared with experiments and analytical formulae. Since most of the studies focus on determining the specific values of some fire related parameters (critical velocity of the ventilated air, backlayering distance of the smoke, maximum temperature in the smoke layer or maximum concentration of smoke pollutants), a lack of research regarding the efficient use of PSDs concomitant with the ventilation system in emergency mode has been identified.