Research On Mechanical Smoke Prevention In Front Room Of Second-Class High-Rise Office Building Based On FDS

Taking a high-rise office building in Dalian as an example,this paper explores the combination of air supply speed and wind direction for the optimal smoke prevention effect through FDS simulation,and solves the problem that the pressure difference between the front room and the aisle is too large due to mechanical air supply.The building has a height of 48 m and a total of 12 floors.The front room is mechanically smoke-proof,and the stairwell is naturally ventilated.Close all the windows of the building,mechanically supply air to the front room on the fire source layer and its upper and lower floors,and open the front room and stairwell evacuation doors on the three floors at the same time.A total of 153 sets of fire scenarios are set up,and FDS is used to simulate,and it is obtained that the air supply port of the current room is set on the top of the front room and on the wall facing the front room entrance.With the effect of location on hazard arrival time,the findings show that:(1)When other conditions remain unchanged,the greater the power of the fire source,the faster the time for the front chamber to reach the dangerous state.Therefore,we should pay attention to the safe storage of articles with high combustion value of fire source.When a fire occurs,we should find ways to reduce the power of fire source in time.(2)The higher the number of layers where the fire source is located,the better the smoke prevention effect under the same conditions,indicating that the chimney effect has a significant influence on the smoke prevention process in the front room.(3)Taking the building studied in this paper as an example,when adopting the air outlet from the top of the front room,it is recommended that the air outlet speed be 4m/s,and the air outlet angle should be 30 degrees toward the front room entrance side.When using the air outlet method facing the front chamber inlet,it is recommended that the air outlet speed be4m/s,and the air outlet angle should be 75 degrees obliquely downward toward the front chamber inlet side.This kind of smoke prevention effect is the best.(4)This paper proposes an air pressure difference automatic adjustment device and adjustment method,which can automatically adjust the residual pressure value of the smoke-proof stairwell or the front room.