الفهرس 
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Abstract
The present study is a numerical investigation of the effect for water mist
on suppression and controls the fire in an enclosure through fire simulation using
FDS code.
The designed model for this study is an enclosed compartment of 4.0m *
4.0 m *2.3 m with a square hole of 0.38 m on the top. A rectangular methanol
and benzene fuel pan with the dimension of 40 cm *40 cm is set in the center of
the room floor and five water mist nozzle are installed at 1.8 m above the floor.
The ceiling gas temperature is calculated with four thermocouples located at 1.8
m above the floor. The model used in this study is validated against the previous
experimental work of Kim and Ryou [43] and the predicted results are in good
agreement with experimental data for temperature field and extinguishment
time.
The heat release rate and radiation attenuation and mean ceiling
temperature are considered as the dominants factors for the safety of building
structure in the fire and through extinguishment process.
The interested droplet size is varied from 50 μm to 250 μm that is located
within the droplet size range for water mist. The dominant factors for fire
suppression are the evaporation cooling of surrounding gas and the reduction of
oxygen concentration around the fire.
The results showed that the fire extinguishment time decreases with the
decreasing droplet size of the water mist. the extinguishment time for methanol
fire with water mist with droplet sizes of 50, 100, 150, 200, and 250 μm are
11,25,25,70,145 seconds respectively. While the fire extinguishment time for
Benzene fire with water mist with droplet sizes 50, 100, 150, 200,and 250 is 14,
52, 58, 176,and 689 seconds respectively.
Also the results showed that for droplet size of 400 μm failed to extinguish
the fire due to the inability of water mist droplets either to direct fire cooling or
oxygen depletion around the fire as the dominant factors in fire extinguishment,
it is found also that there are two different regimes for smoke layer temperature,
one is the initial sudden cooling regime and the other is the gradual cooling one