| Along with the rapid spread of low-carbon development in the world,all industries are actively transforming to green energy saving.In the construction process of the building industry,it is especially critical to reduce the energy consumption of the building envelope.Polymer insulation materials are widely used in the envelope of high-rise or super high-rise buildings because of their excellent thermal insulation properties.But the insulation material is very flammable characteristics,is ignited will quickly spread to form a large-scale three-dimensional combustion,while producing a large number of toxic hightemperature smoke,thus seriously endangering people’s lives and property safety,coupled with modern building structure design diversification,restricted wall configuration will lead to combustion heat feedback mechanism changes,so that the building adjacent to the wall composition of the corner configuration insulation system there is a great safety hazard.In this paper,for the proposed building corner configuration thermal insulation material fire,respectively,single/double ignition source conditions under the polyurethane insulation material downstream fire spread experiments,and set different building corner configuration,to explore the number of ignition sources and the number of fire spread law under the coupling effect of the corner configuration,analyze the thermal feedback mechanism between adjacent walls,reveal the effect of the corner effect on the fire spread within the configuration,so as to build a corner configuration fire spread The theoretical model of the characteristic parameters of the nip configuration was constructed.The analysis shows that under the single/double ignition source,the flame is transformed from longitudinal one-dimensional linear spread to two-dimensional plane spread,and the top transverse fire spread rate is greater than the bottom transverse fire spread rate,so the flame front is tilted,and the tilt degree increases with the increase of the configuration angle,and the difference between the top and bottom transverse fire spread rates gradually decreases.The peak temperature of the surface measured by the thermocouple array is symmetrically distributed;in the case of a small configuration space with a single fire source,the heat accumulates,the material is fully pyrolyzed,the hightemperature region is covered more widely and the low-temperature region is covered less,the maximum temperature of the left and right sides of the plate can reach 750℃,and the peak temperature of the preheating zone of the neighboring plate is linear with the angle;in the case of a double fire source,a fused inverted "V" flame is formed at the middle angle."The mass loss can be divided into three stable stages,and the maximum percentage of mass loss shows a stepped upward trend,of which the maximum mass loss can be up to45.88% at the time,indicating that a proper acute angle configuration has a larger restricted space,which can promote air absorption in the space,making the material burn more fully,and the greater the mass loss,the higher the maximum temperature of the left and right sides,The average value of longitudinal temperature on the left and right sides is higher than the longitudinal temperature at the angle,the longitudinal temperature at the left plate and angle is negatively correlated with the angle,and the flame pulsation frequency is linearly negatively correlated with the angle of the configuration angle,with the maximum value up to 11.96Hz;the dual fire source combustion promotes the flow of smoke in the vertical channel,enhances the rate of air coiling,accelerates pyrolysis,and makes the combustion more intense,and the average rate of mass loss and fire spread is much higher than that of the single ignition source The average mass loss rate and fire spread rate are much higher than those of single ignition source,and the segmental stability of mass loss is also more significant,while the temperature distribution is more uniform under single ignition source conditions.Figure [55] table [4] reference [74]... |
PDF Full Text Request