Temperature profile of thermal flow underneath an inclined ceiling induced by a wall-attached fire

Abstract

The present study for the first time investigates the temperature profile of thermal flows underneath an inclined ceiling induced by a wall-attached fire plume. This kind of thermal flow configuration could happen practically when a fire occurs near the wall of a building with inclined roof, however, has not been quantified in the past. Experiments were conducted in this study employing a square burner attached to the wall as the fire source. The fire plumes rise up along the wall and impinged upon an inclined ceiling. The temperature profiles in the direction normal to the intersection line of the wall and the ceiling were measured for various fire source heat release rates, source-ceiling heights and ceiling inclination angles. Results showed that the inclination angle of the ceiling has no considerable effect on the maximum temperature rise (above ambient) underneath the ceiling in the fire plume impingement zone. However, for the outer-impingement zone, the temperature rise at a given distance from the impingement zone increased with the increasing of the ceiling inclination angle. The effect of the ceiling inclination angle on the temperature decay profile is more significant for smaller source-ceiling height and larger heat release rate. When the ceiling inclination angles were positive, the temperature rise becomes close to each other with the increasing of the distance from the fire plume impingement zone. While as the ceiling inclination angles were negative, the temperature rise decreased sharply along the ceiling and become much smaller than that of the positive inclination angle. A correlation was proposed for the maximum temperature rise underneath the ceiling based on the continuity in the fire plume impingement zone. And the temperature decay profiles for various ceiling inclination angles were described well by a formula proposed to include the effect of the inclined ceiling.