Experimental and simulation study on a novel uniform air/smoke exhaust device in subway

A novel π-shape device (π-D) was developed based on air full pressure supply theory to realize the uniform air/smoke exhaust for long duct with enormous vents in subway tunnel. To validate its performance, numerical simulation of internal flow field of the duct with π-D was conducted. Then an experimental 65-meter-long exhaust duct with π-Ds was set up in accordance with the real size. The air exhaust velocities of each vent and the total head losses along the main duct were measured. Both experimental and simulation results showed that the proposed new device could be designed and equipped flexibly into the long air/smoke exhaust duct. It would significantly enhance the ventilation uniformity, reduce the airflow resistance by 50%-65%, and achieve above 20% of distribution energy saving as well.