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Volume 29 (1979)
- Issue 2 Pages 41-
- Issue 1 Pages 1-
Volume 29, Issue 2
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Paper
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R. I. EMORI, K. SAITO1979 Volume 29 Issue 2 Pages 41-49
Published: 1979
Released on J-STAGE: December 21, 2012
JOURNAL FREE ACCESSTo develop countermeasures for fire hazard, it is most desirable to perform experiments on real fire, but in many cases, it is not practicable. There are many reasons : it is dangerous to put a fire on a large building, full-scale fire experiments are not feasible economically, a large number of experiments must be required for many types of buildings, and so on. Here, it is more desirable to do fire experiments on scale models in a laboratory under controlled boundary conditions. The first and the most important thing in model experiments, however, is to prove the similarity between the original phenomena and the scale model counterpart.
This paper describes experimental verification of model rules on movement of smoke and poisonous gases which are one of the main causes of disaster in fire. The model rules were obtained by the “law-approach” that calls for physical interpretation of the phenomena to bring out the governing physical laws. Two geometrically similar L-shaped corridors were built with the length scale of 5.5 to 1. A fire was set at one end of the confined corridor, and temperature and velocity distributions were measured at several points of the corridor. The result showed a remarkable similarity in the two corridors and the model rules seemed to be well confirmed. The flow at the elbow of the corridor was observed to be similar to the two corridors. This also indicates the validity of the model rules to extend the result of models to full scale fires.View full abstractDownload PDF (765K) -
T. TANAKA1979 Volume 29 Issue 2 Pages 51-60
Published: 1979
Released on J-STAGE: December 21, 2012
JOURNAL FREE ACCESSThis report describes a model to analyse the behavior of fires in small scale buildings e. g. home fires.
First, we determined the course of the fire modeling. And we divided the whole process of building fire into the two stages, i. e. the initial stage before flashover and the fully-developed stage after it to make the modeling easier.
Next, we consider mass and energy conservations and state of the hot gas layer and air layer of each room in building. And from these consideration, we derive ordinary differential equations for temperature and depth of each hot layer and a flow-control equation of each room.View full abstractDownload PDF (817K) -
T. TANAKA1979 Volume 29 Issue 2 Pages 61-71
Published: 1979
Released on J-STAGE: December 21, 2012
JOURNAL FREE ACCESSFor analysis of fire, it is important to properly estimate the heat release by combustion and various heat transfers.
The calorific values of the combustion in actual fires differ from experimental one because the fuels contain water, the fuels leave residual char, and the formation systems do not go back to standard temperature of original system. It is necessary to clarify the relation between the two combustions, because we have to estimate the heat release in actual fire from experimental calorific value. For this purpose, we introduce a simple model of wood pyrolysis which is based on Thomas et al., and the definition that pyrolysis means to pyrolyze combustibles into elementary composition, C, H2, O2. Using the model and the definition, we can easily estimate latent heat of pyrolysis and heat release of the material whose elementary compositions and experimental overall calorific value are known.
We can effectively estimate thermal radiation heat transfer by assuming that hot gas is gray and developing Net-Radiation Method. Of course we have to simplify the heat transmission system, because spaces in buildings are in general very complex. But in many practical cases in the analysis of actual fire, considerable simplification may be acceptable.View full abstractDownload PDF (826K)
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