Prediction system and prediction method for building fire smoke flow feature

Abstract

The invention requests for a system and a method for predicting fire fume characteristics to protect buildings and relates to predicting of fire fume development and evolution laws in high-rise buildings and multi-layer and multi-room buildings. The invention constitutes a complete building fire fume characteristic predicting system and a fire fume characteristic predicting method. A building is transformed into a building ventilation tree composed of nodes and branches so as to construct a junction matrix and a closed-loop matrix for ventilation circuits of the building; a fume characteristic equation is composed and solved to plot the relationship of time and concentration changes of CO2 and CO, then the time to reach the dangerous concentration is predicted. The system can predict the structure changes of the building during the development of the fire so as to make out forced ventilation proposals and smoke control and exhaust proposals for each part in the building and realize performance-based design of smoke prevention and exhaust systems and safety evacuation of the building with the maintenance of the fire safety.

Description

technical field [0001] The invention belongs to the field of fire safety and fire engineering, and in particular relates to a prediction of the development and evolution law of fire smoke in high-rise buildings and multi-storey and multi-room buildings. Background technique [0002] Since the 1970s, some developed countries in the world have begun to conduct systematic research on performance-based building fire protection design methods, and various mathematical and physical models have emerged to describe the characteristics of smoke movement, mainly including field models. , regional model, network model, and a hybrid model that combines the above three models. For high-rise buildings and their multi-storey and multi-room buildings, due to the large amount of restricted space and very complex boundary conditions, network models are mostly used in the world to study the fire smoke movement of such buildings. There are mainly the BRI model developed by the Architectural Re...

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Problems solved by technology

[0003] That is, only the smoke concentration is taken as a function of time, or only the physical parameters of the fire chamber are taken as a function of time, and the temperature of other parts of the building in the fire is regarded as constant; in terms of heat transfer calculation, only the high-temperature smoke The heat transfer from the gas to the surface of the wall, while ignoring the heat transfer from the wall to the adjacent room, will inevitably lead to deviations in the calculation of the room temperature of the adjacent room; the thermal physical parameters of the flue gas, such as thermal conductivity, constant pressure specific heat capacity, density etc. are simplified to constants, which is very different from the actual situation and does not conform to the law of fire development and evolution; the heat release rate of the fire source in the fire is mostly a steady-state fire source, which can make the calculation simple, but its disadvantages It is obvious that the set power of the steady-state fire source is often determined based on empirical data, its nature is not clear, and it cannot truly reflect the output of the heat release rate of the fire source

Moreover, in common building fires, solid combustibles account for the vast majority, and the fire load density is very high. The output of the heat release rate of the fire source changes with the development of the fire, which is a function of time, such as the heat release rate of the fire source It is very likely to underestimate or overestimate the fire risk and reduce the accuracy of the calculation results

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