Numerical Simulation Of Natural Smoke Exhaust Characteristics In The Patio Of Super High-Rise Residential Building

In recent years,science?technology and economic have made great progress,a large number of super high-rise buildings have emerged in various countries in the world.While satisfying people's demands to the function of the buildings,it also alleviates the land pressure caused by the increase in population density.In order to solve the problems of ventilation and lighting of high-rise buildings,more and more buildings are equipped with patios that run from the bottom to the top of the building,but in the fire,the patio will cause a "chimney effect" and a great threat to the residents around the patio.In this paper,the characteristics of smoke movement and the characteristics of natural smoke emission during the fire in the high-rise residential building are studied by combining theoretical analysis with FDS numerical simulation.Firstly,on the basis of previous research,a continuous model of the neutral surface of the patio is established.The results are compared with the FDS numerical simulation method.The error between the continuous model of the neutral surface and the FDS simulation results is 4.3%,and the neutral plane position is located lower in the middle position of the patio.Secondly,taking hazard occurrence time,smoke movement speed,mass flow rate,temperature and other factors into account,the FDS numerical simulation method is used to study the influence of the opening and closing state of the outside windows of the high-rise residential building,the dimension of the patio,the location and size of the fire source and the ambient wind on the natural smoke exhaust characteristics of the patio.The simulation results show that:1.When the fire source is located at the bottom of the patio,the windows of the surrounding houses facing the patio remain open,if the outside windows of the houses are all kept open,the natural exhaust effect of the patio is better,and the surrounding houses will not reach a dangerous condition;if the outside windows are all closed,the surrounding houses may be in a dangerous condition affected by the smoke in the patio.2.The hazard occurrence time and the patio height satisfy the quadratic growth function,and the hazard occurrence time tends to stabilize as the height increases.3.The patio length has a critical value.When d?10m,the dangerous time and the patio length satisfy the quadratic growth function;When d>10m,the dangerous time approaches the stable value.4.When the fire is located in the house around the patio,if the sprinkler system inside the house is effective,other houses around the patio will not be in danger;if thesprinkler system fails,other houses around the patio may reach a dangerous condition.When the fire is located at the bottom of the patio,if the fire source power is less than 1.5MW,the houses around the patio will not be in danger,if the fire source power reaches 4.0MW,other houses around the patio may reach a dangerous condition.5.When a fire occurs at the bottom of the patio,the houses on the leeward side is greatly affected by the smoke and may reach a dangerous condition.When a fire occurs in the surrounding houses,under the influence of the environmental wind,the adjacent houses above the fire floor and the houses above and below the refuge floor are more affected by the smoke,they may reach a dangerous condition,and the rest of the houses are less affected by fire smoke.