Optimization of Mechanical Smoke Exhaust System Design for Metro Underground Vehicle Base Application Library

Objective The adoption of fully underground mode for metro vehicle base enhances economic efficiency while increases the difficulty of smoke exhaust after a fire emergency. It is necessary to conduct an in-depth study of key parameters that influence the effectiveness of mechanical smoke exhaust system in underground metro vehicle base application library. Method Using the underground vehicle base of a metro line in an East China city as research object, a numerical simulation model is developed using FDS（fire dynamics simulator）, and the reliability of this model is verified. In accordance with GB 51298-2018, smoke exhaust volume, distance between smoke-prevention vertical curtain bottom and exhaust outlet, and smoke exhaust outlet number are selected as parameters, a numerical simulations for the smoke exhaust performance is conducted under different values of the above three. Result ＆ Conclusion The design of mechanical smoke exhaust systems for underground metro vehicle base should aim to minimize economic losses and environmental impact while ensuring the safe personnel evacuation within the available safe evacuation time under all operating conditions. The recommended values for the three parameters are as follows: the smoke exhaust volume should be no less than 21 m³/s; the distance between the bottom of smoke-prevention vertical curtain and exhaust outlet should be no less than 1.0 m; the number of exhaust outlets has a relatively minor effect on smoke exhaust performance and can be determined comprehensively based on factors such as maximum allowable exhaust volume, air leakage, and vertical space utilization.