Research On The Smoke Flow And Control In Atrium-style Metro Station Fire

The interior design of metro station is not simply gaining floors, but to apply thedesigning methods of above-ground buildings to underground building. However,challenging to the system function design is increasing with the improvement of spaceusage. The metro station is comparatively enclosed with small numbers of entrances andexits and high crowd density. As a result, the atrium space will make the interior functionsystem complicated and make it difficult to prevent and discharge smoke at the time of firewhen the metro station is full of heat and high temperature flue gas. So it is a major task foratrium-style metro station to provide secure smoke contrl system and safeguard passengers’lives.With a1/15portion scale model of a atrium-style metro station built according toprinciple of similitude, this project divids smoke control zone1into station hall, Atriumsmoke control zone, sub-platform smoke control zone1, and sub-platform smoke controlzone2in condition of both no-air condition pattern and mechanical smoke exhaustingpattern by building smoke prevention procedure of smoke barrier and dividing smokecontrol zones. The fire HRR of the protyped station hall is2.5MW, and both those of theplatform and artrium are7.5MW. In accordance with the above protyped figures, thesimulated fire HRR of each part are2.9KW and8.6KW. At first it observes the maximumrange of fire and the rules about the fire smoke filling movement of the atrium without aircondition system. And then it simulates mechanical smoke exhausting under differentworking conditions, and accordingly makes it clear under what degree of smoke rate canfire and smoke be controlled effectively, and draw conclusions as follows:(1) When fire happens in sub-station hall smoke control zone1, smoke can beeffectively controled by mechanical smoke exhausting under Condition2.(modeling airchange rate of133.3times per hour in accordance with34.4times per hour of the protype)(2) When fire happens in sub-atrium smoke control zone, with mechanical smokeexhausting under Condition2(modeling air change rate of88.4times per hour inaccordance with22.7times per hour of the protype), smoke holds up in the side close tosub-station hall smoke control zone4as the top of atrium divided into two parts by theoverpass, and some portion of smoke spreads to sub-station hall smoke control zone4overthe smoke barrier. This circumstance satisfies needs of self-lifesaving according to themodel experiment.(3) When fire happens in sub-platform smoke control zone1, with mechanical smokeexhausting under Condition2(modeling air change rate of150.2times per hour inaccordance with38.8times per hour of the protype), smokes can be effectively controled insub-platform smoke control zone1with only small part spread to the atrium, which hardly prevents self-life saving for persons in atrium.(4) When fire happens in sub-platform smoke control zone2, under Condition1, themodeling air change rate should reache at least318.8times per hour in accordance with81.3times per hour of the protype, smokes can be effectively controled with some part stillspread to the atrium, which does not treat self-life saving there.Based on the above conclusions, FDS, a kind of software, is applied for numericalmodeling in different fire senarios. It mainly simulates density field temperature field andspeed field, in different fire scenarios in effective working condition, observes andcompares different smoke movements, therefore provides certain theoretic support forsmoke prevention and exhausting, fire controlling, and self-life saving in atrium-stylemetro stations.