The Numerical Simulation Of Fire Smoke Movement And Control In The Stairwell And Elevator Shaft Of The High-rise Building

The number and size of high-rise buildings are promoted by the rapid of economic development and the acceleration of urban construction pace. The fire may cause serious human casualties and economic losses because the fire safety design in high-rise buildings is lack of comprehensive. With the increase of the height and saturation in high-rise buildings, it can cause many problems using stairwell to escape, such as more time to waste, easy to jam, etc. Now the feasibility of applying elevator to escape has been raised by experts. However, it is not only harmful to escape, but also beneficial for smoke to spread quickly to other floors if the smoke moves into the vertical escape evacuation routes while it is on fire. Therefore, it is very important to study smoke movement and its control in the stairwell and elevator shaft.Smoke movement is very complex in the stairwell and elevator shaft. Being an escape passageway,in order to reappear its fire process the detail space-time distribution field model of physical quantity should be set up and accurate and reliable numerical simulation should be carried up. Therefore, FDS is used in the thesis, which are current international recognized and most reliable smoke flow computational fluid dynamics software.According to the chimney effect mechanism and the piston effect theory, the influence factors of the smoke movement in the stairwell and elevator shaft are analyzed, a typical physical model of vertical evacuation routes is set up and computer simulation is carried out. In the end the smoke motion characteristics are obtained in the thesis. The study shows that the smoke movement velocity in the elevator shaft fills rapidly (up to 3.3m/s) because of the role of the chimney effect. The smoke movement in the stairwell is very complicate and increases slowly because of the stair. The difference temperature and air of indoor and outdoor, can affect the pressure distribution of the high-rise building and the smoke velocity. The innovation of the thesis is the dynamic simulation of the smoke movement effected under the different moving conditions of elevator. The pressure between antechamber and architectural space is increasing first and then decreasing. The movement downward of elevator can reduce the smoke spread in a certain extent,meanwhile the movement upward of elevator can accelerate the smoke spread to other floors.The several different mechanical pressure air supply systems are simulated by analyzing the style of pressurization air supply system, air volume and its influence factors.The study shows that the stairwell or pre-chamber pressure air supply could make smoke get into the stairwell and elevator shaft, and the smoke movement could affect mechanical pressure air supply and it is harmful for the people to escape. The effect of pressurized air supply system in the stairwell and pre-chamber pressure is better and can satisfy to the evacuation requirements.The conclusions of the thesis would be useful to fire safety design of the high-rise building.