Simulation Of Fire Temperature Field For Large Space Air-supported Membrane Structure

Large space air-supported membrane structure is widely used in all kinds of buildings because of its vast interior space,beautiful architectural appearance,short construction period and low construction cost.Due to the large internal space and the characteristic of the airtight type of the structure,the smoke generated by the combustor will quickly spread and fill the internal space of the air-supported membrane structure.The internal temperature of the structure will continue to rise,and the visibility will continue to decline.In this situation,people’s lives and property will be threatened.Therefore,it is of great significance to study the internal temperature field distribution and rule of exhaust gas flow in air-supported membrane structure.This paper focus on the problem of temperature field of rectangular air-supported membrane structure,and use FDS to study that how the fire source parameters and structural parameters influence temperature field distribution inside the rectangular air-supported membrane structure;Several smoke control schemes are compared and analyzed in this paper,and the smoke control methods for rectangular air-supported membrane structure are given at the same time.The temperature distribution curve describing the inner surface temperature of the roof is proposed.The main work included following aspect:(1)The accuracy and reliability of FDS to simulate the temperature field of air-supported membrane structure are verified from three aspects: the temperature of fire source and membrane surface,the time required for membrane burning through and the area of membrane burning through hole.The simulation of membrane burning through is realized by combining the life and death unit provided by FDS with membrane burning characteristics.(2)Through a large number of numerical simulation,the influence of fire source parameters(fire power,fire source location),structural parameters(structure length-width ratio,structure rise span ratio,smoke control system)on the temperature field distribution and smoke flow in the structure is analyzed comprehensively.With the increase of fire source power and rise span ratio of structure,the maximum temperature inside the structure increases;when the fire source is located at the edge and corner of the structure or the length width ratio of the structure is too large,the temperature field in the plane at the same height inside the structure will be uneven;when the fire source power and rise span ratio of the structure increase or the fire source is near the middle of the structure,the CO concentration inside the structure will rise faster,and in evacuation The maximum CO concentration at the height of 2m at the door will increase;when the length width ratio of the structure is increased or when the fire source is located at the inner edge and corner of the structure,the visibility of the plane at the height of 2m inside the structure will decrease faster.(3)Change the size of smoke exhaust hole,smoke exhaust mode,smoke exhaust position and smoke exhaust wind speed of smoke exhaust,set different smoke exhaust schemes,and make a comparative analysis of the simulation results,and evaluate the smoke exhaust effect of each smoke exhaust scheme from the internal temperature,CO concentration and visibility of the structure.The smoke exhaust scheme is arranged as follows according to the smoke exhaust efficiency: the active smoke exhaust scheme with the combination of air inlet and exhaust is adopted > the smoke exhaust scheme with only exhaust window arranged > the smoke exhaust scheme with natural smoke exhaust window arranged.(4)The characteristics of temperature distribution of rectangular air-supported membrane structure roof are analyzed,and the temperature distribution curve was proposed.