Regional Simulation-based Indoor Fire Heating Curve

As an important input condition of structural fire resistance design,the temperature-time process of compartment fire has a direct impact on the results of structural fire resistance design.Currently, the standard temperature-time curve (ISO834) is mainly adopted to check the fire resistance of components in the structural fire resistance design. Accounting that this method has many disadvantages, so we need to obtain a new T-t curve whose properties are more closer to the actual indoor fire,to improve the standard testing. Zone model is a deterministic analysis model of fire modeling, who plays a very important position in the compartment fires. Therefore, the fire of single-room is chosen as our research object in this dissertation. Starting from the physical phenomena of indoor-fires,through classifying the indoor-fire into two types which include fuel-control and ventilation-control,the mathematical models are established respectively by using two-layer or single-layer zone model. A program which can be used calculating the actual temperature-time curve of indoor-fire is developed on the basis of zone models. The main jobs in this paper are as follows:(1)A comprehensive study on the compartment-fire is conducted, which involves general fire development rule, the relevant parameters and the heat transfer process. The main factors affecting the temperature rise are also analyzed and the existing fire temperature-time curves are researched. In addition,the importance of classifying the indoor-fire into two types(fuel-control and ventilation-control) is pointed out.(2)After a comprehensive comparison among three fire HRR models usually used,a t-squared fire source model is determined to construct the whole process of the fire,in which the maximum HRR is given previously.(3)The zone mathematical model of ventilation-control and fuel-control fire room is derived respectively in detailed. A series of mass and energy conservation equations are established which have taken full account of all of the fire sub-processes.These sub-processes include the plume, the ventilation flow, the wall heat transfer process.The numerical methods of these equations are also analyzed. Finally,a more mature zone model theory of indoor-fire which based on previous research has formed.(4)A program which can be used calculating the actual temperature-time curve of indoor-fire is developed on the basis of zone models.The procedure is visualization and easy to operate.In the program, the parameters input interface and output interface are developed which make it easier to input different rooms and environment parameters,and then calculate and display the indoor-fire temperature and the smoke layer height curve.(5)By using the program developed,the temperature-time curves of three different fire rooms are demonstrated,including types of fuel and ventilation controlling.The results show that the shape of temperature curve has relationship with multiple parameters,which include the fire source model, plume model, spatial parameters, the opening factor, the make up air,the thermal properties of the wall,et al. The curve varies if one of these parameter changes. Procedures developed in this paper can be applied to architectural design phase, and provide the necessary basic data for analyzing damage of the building components in the fires.