热释放速率方法
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TABLE OF CONTENTS
ABSTRACT ..................................................................................................................... I
TABLE OF CONTENTS ..................................................................................................... II LIST OF TABLES............................................................................................................. III NOMENCLATURE ...........................................................................................................IV
CONCLUSIONS ................................................................................................................ 7 REFERENCES .................................................................................................................. 8
m ′′
′′ m∞
.
.
∆H c heat of complete combustion (MJ/kg)
Q
Q0
k
.
.
total heat release rate of the fire (W) initial heat release rate extinction-absorption coefficient of the flame (m-1)
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NOMENCLATURE
Av Af D t tb
burning surface area (m2) horizontal burning area of the fuel (m2); pool diameter (m) time (s) burn time (s) mass loss rate unit area (kg/m2s) mass loss rate per unit area for an infinite pool (kg/m2s)
Greek Symbols
α χ β
constant for a particular fuel of a fuel package (kW/s2) combustion efficiency mean beam length correction for the flame
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Heat Release Methods
By A. Bounagui, N. Benichou and A. Kashef
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INTRODUCTION
The move to performance-based codes, the increase complexity of building design, the progress made in the understanding of fire phenomena and the advances made in computer technology have led to the increase use of computer fire models. Heat release rate is the most important parameter that is required as input to zone and field models since it controls the characteristic of the fire. Therefore, the Fire Research Program at the Institute for Research in Construction has developed a heat release rate tool1 that groups different heat release methods found in the literature. The tool allows the users to create heat release rate data from various methods and convert the data into the format suitable in commonly used zone and Computational Fluid dynamics (CFD) fire models. This report presents the heat releases methods that have been implemented in the tool.
Heat Release Methods
Research Report 186
பைடு நூலகம்
Date: 19 January 2005 Authors: Abderrazzaq Bounagui Noureddine Bénichou Ahmed Kashef
Published by Institute for Research in Construction National Research Council Canada Ottawa, Canada K1A 0R6
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2.1
HEAT RELEASE METHODS Heat Release Rate Prediction from Statistical Data
Based on the work of Hoglander and Sundstrom2, two methods have been derived from the Combustion Behaviour of Upholstered Furniture (CBUF) database to predict the heat release rate for domestic and public furniture. The expressions of the heat release rate as a function of time for both types of furniture are as follow: 2.1.1 Domestic upholstered furniture
2.1 Heat Release Rate Prediction from Statistical Data ..................................................... 1 2.1.1 Domestic upholstered furniture................................................................................... 1 2.1.2 Public upholstered furniture ........................................................................................ 1 2.2 2.3 2.4 2.5 2.6 Time-squared Heat Release Model ................................................................................. 2 Semi-Universal Fire .......................................................................................................... 4 Upholstered Furniture Fires ............................................................................................ 4 Pool Fires ........................................................................................................................... 5 Wood Pallets ..................................................................................................................... 6
ABSTRACT
Heat release rate is one of the main inputs to zone and Computational Fluid Dynamics (CFD) fire models. It defines the fire size and its growth. This report presents the various methods found in the literature that have been used to predict the heat release rate. These methods are also grouped in the heat release rate tool (HRRTool) that is being developed in the Fire Research Program at the Institute for Research in Construction. HRRTool allows the user to select the method of choice and generate the heat release data in the format required for input in CFD and zone fire models.
