EXPERIMENTAL STUDY OF THE RADIATIVE HEAT FLUX DURING WATER MIST FIRE SUPPRESSION IN AN ENGINE COMPARTMENT
Résumé
Thermal radiation is one of the most important factors that must be understood in the field
of fire safety in order to improve radiative protection capabilities and prevent bigger hazards. In this
context, fire protection systems are essential parts of military vehicles, with water mist being one of the
systems potentially applied to protect the engine compartment. Water mist not only has the potential to
extinguish the fire but is also effective in reducing the radiation effect. In this study, a scale 1 test bench
of a military vehicle's engine compartment has been developed. Total and radiative heat flux sensors
were placed in the test bench compartment in two positions with different orientations to evaluate the
heat flux in the compartment with and without a water mist system, along with the effect of the airflow
velocity generated by a radiator fan. A thermocouple tree was placed inside the test bench above the fire,
and a thermocouple also was placed around the heat flux sensor to study temperature evolution. A gas
analyzer was also used to evaluate the gas concentration. The result shows that the heat flux sensor's
orientation affects the radiation to total heat flux ratio. The water mist show has an effect of reducing
rapidly the radiative heat flux as well as the temperature maximum and temperature average on the
thermocouple tree after activation. The total heat flux and the temperature around the heat flux sensor
increase shortly after activation and then decrease. CO concentration shows an increase after water mist
activation. The airflow velocity shows an effect on the maximum radiative heat flux