Building Indoor Common Wood Fuel Thermogravimetric Analysis And The Numerical Simulation Of Combustion

Fire is the fire spread out of control due to the severe phenomenon,is one of the very high frequency and devastating disasters,building fire prevention is an important part of disaster prevention and mitigation in China.Along with our country economy fast development,people living environment improved increasingly,species diversity,performance is multifarious wooden furniture and decoration materials,more and more appear in modern architecture.Most of this kind of new building materials containing a large number of flammable and combustible polymer,when burning may release a large amount of smoke and toxic gases,has the potential of fire safety hazard,and based on the combustion characteristics of materials research in China is less,started late,has not yet formed complete material fire characteristics of the database.Based on construction of the common wood fuel indoor thermogravimetric analysis and numerical simulation research.Building indoor common density board,sandwich board,joinery board,particle board four woody fuel as the research object,using thermogravimetric analysis,the pyrolysis characteristics of different materials and different heating rate,particle size,the influence of different atmosphere on the pyrolysis characteristic,provide the basis for establish a complete material fire characteristic database;Using Origin8.0 software for air and nitrogen atmosphere density board,sandwich board,joinery board and particieboard mechanism function selection and establish the dynamics model of the Coats-Redfern dynamics analysis to characterize the material dynamic characteristics of activation energy E and frequency factor A,choose for building indoor fire safety,decorate wooden materials provide basis;Selection of activation energy and frequency factor compared to the highest sandwich panel as the research object of ISO 9705 full-size combustion experiment,obtain combustion process,the change of the temperature field,temperature and heat release rate were simulated and experiment data,verify the FDS simulation results can be reference and select the best grid precision of simulation calculation for sandwich board combustion process ZhongYan aura,for fire prevention and rescue,building indoor fire prevention design and wood decoration materials such as flame retardant research provides the basis.The results showed that:(1)The density board,sandwich board,joinery board and particieboard pyrolysis process can be divided into water,mild weightlessness,sharp weightlessness and carbonized four stages.With the increase of heating rate,the four samples pyrolysis water loss peak and sharp weightlessness peak are different degrees of high temperature direction deviation trend;Particle size is fine,4 kinds of hemicellulose sample weight loss rate,the greater the hemicellulose weightlessness peak,the more obvious;Besides particieboard is smaller,the other three sample air atmosphere pyrolysis process significantly faster than nitrogen atmosphere,reaction than nitrogen atmosphere more fully,reduce the quality of residue.(2)The density board,sandwich board,joinery board,particle board under nitrogen atmosphere the best mechanism of function is ?2,sandwich board compared to the activation energy and frequency factor is highest,namely burning the energy needed most;Air atmosphere density board,and joinery board the best mechanism of function is-ln(1-?),the best mechanism of sandwich board and particieboard function as the ?2,sandwich board compared to the activation energy and frequency factor is highest.(3)Under different grid precision,FDS simulation results can better said sandwich plate burning process,can be reference.Measuring point,the nearer to the center of the fire is the FDS simulation results,the greater the effects on temperature measurement accuracy;The fine mesh precision,at the same point FDS simulation results with the ISO 9705 degree is higher,the thermocouple measurement results consistent with the in computer performance conditions allow,should choose to simulated analysis of working condition of a finer mesh precision.(4)Sandwich board in the combustion process,the farther away from the center of the source of a thermocouple position,compared to the measured temperature value is lower;Thermocouple location near the fire center or lower part of the door,measuring point temperature curve change.Sandwich board simulated the combustion process,the single indoor visibility from 30 m fell sharply to 0.9 m after tending to balance;CO2 volume fraction is the overall trend in stable state after rising first,increases with the vertical position of measuring points,CO,CO2 volume fraction curve upward trend in turn.