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Abstract
Smoke is the deadliest factor in the event of subway fire because it spreads in direction coincide with passenger’s evacuation path. It reduces visibility and can cause deaths by suffocation (known as the silent killer). This work presents a numerical study on the optimization of smoke ventilation mode at the conjunction area between the tunnel track and the platform in a situation of a train fire at a subway station. The present study investigates the effectiveness of smoke control or smoke ventilation utilizing an over track exhaust (OTE) fan. The fire dynamics simulator (FDS) program is utilized to simulate a subway car fire source with a steady heat release rate resulted from burning heptane as a fuel. The model dimensions are 150-m long, 22-m wide, and 19-m in height. The station contains three levels (platform level, intermediate level, ticket level). Planar slices base calculations on the time of smoke spreading, people evacuation period and measurement of the (visibility, velocity, CO concentration), before and after applying the control. The results show that, before applying the control, the Smoke gradually filled the station from 0 sec to 600 sec. The vision became absent, and the smoke is expected to cause suffocation accompanied by death. The temperature value arrived (310) °C at platform level. Smoke velocity value arrived (4.9) m/s. Carbon monoxide value arrived 50 (ppm). Visibility value arrived (1.6) m. After applying the control utilizing OTE fans, the temperature value arrived at right platform level (60) °C. Smoke velocity value arrived (10) m/s. Carbon monoxide value arrived (15) ppm. Visibility value arrived (21.5) m. by using extraction system, Results show that smoke spreading was reduced, which suppressed the suffocation, and the visibility was a good clear during the last passenger get out from the station at time 190 sec ,Preserving property and equipment from fire, helps firefighters to enter the fire site and control the fire before it spreads.