- Author
-
Voigt, U.
|
Wolf, H.
- Title
- Verfahren zur Berechnung der Offnungen bei industriellen Hallenbauten im Brandfall. [Method to Calculate the Size of Openings for Smoke and Heat Release Out of Industrial Halls in Case of Fire.]
- Journal
-
VFDB,
No. 1,
25-31,
February 1991
- Keywords
-
corridors
|
smoke
|
heat release
|
mathematical models
|
temperature
|
density effects
|
fire gases
- Abstract
- To achieve the aimed at smoke- and heat release out of a room in fire the buoyancy resulting from differences of temperature or density can be used effectively. Therefore tests were made to work out a simplified mathematical model to simulate such a fire and to get the connection between temperature and density of the fire gas layer and the transformed amount of fire substances per time unit. They were transferred into a computer program. Basis of these model equations are the mass and enthalpie balances on the differential time element. A system of two coupled first order differential equations was derived for fire gas temperature and thickness of the fire gas layer as a function of time. This system was resolved by using a free-jet model for the smoke expansion as an initial value problem. Verification of this model was made by fire tests in a 1000 m fire research hall and in a 200 m test stand. It was found out, that the mathematical model is able to predict the temperature and the thickness of the fire gas layer with an insecurity factor of 10-20%. The mathematical model as well as the EDP-programe has been confirmed in solving problems of smoke- and heat transfer.