Numerical Study On Fire Smoke Flow And Smoke Control In Underground Garage

With the rapid development of china’s economic construction, the undergroundgarage became a key construction project of the city underground space of our countryin recent years. Underground garage has three major characteristics, with smoke whenhas the fire, high temperature, low visibility fire cause greater damage to property, andhas certain limitations about the specification of the underground garage, so it isnecessary for us to study the smoke regularity of underground garage.This dissertation first analyzes the reasons and characteristics of fire inunderground garage, introduces the control of fire smoke flow and the research status athome and abroad, determines the main content in the research of this topic. Then mainlyintroduced the gas flow rule and its research methods, on the basis of analyzing theadvantages and disadvantages of several methods, this dissertation chooses largeeddy simulation technology which belongs to the field simulation level of, and selectsthe FDS fire simulation sofeware which released by NIST of United States for theunderground garage fire smoke flow rules and flue gas control research.By means ofthe fire experimental data from University of Science and Technology of china’slaboratory and comparing the numerical simulation results of us to verify the reliabilityof FDS fire simulation software. Then use FDS for simulation studies about the flue gasflow and control methods of an underground garage, on the basis to establish the realsituation of the physical model as close as possible, to determine heat release rate of themodel, smoke extraction volume and simulation time, analysis four different conditionsthe arrangement, the wind speed, the area of smoke vent and fill air volume etc on theinfluence law of smoke layer development and fire control, concluded the flue gasdiffusion concentration diagram under different fire scenarios, temperature distribution,visible distribution of underground garage. Results show that the side smoke exhausteffect is better than bottom smoke way; When the smoke vent wind speed is fixed, theaera effect is not big; Fill the appropriate increase air volume can be reinforced platoonsmoke effects, but to fill air volume shoulds not be too large, otherwise it will increasethe amount of oxygen on fire area, increase the strength of the fire. Finally on the basisof fire simulation, this dissertation analyzes the fire dangerous state of time, thendetermine the available safe egress time ASET. determine the personnel safetyevacuation time REST, that is the model simulation time which, we calculate by Togawa empirical formula in front of, the final judgment in different fire scenarios and safetywhether personnel evacuation.