doi:10.3850/978-981-08-7724-8_03-03

ABSTRACT

Understanding ceiling jet flow characteristics is important, because the ceiling jet becomes a trigger for occupants to take an action for fire fighting or evacuation. Many researchers have developed experimental and theoretical approaches and easy-to-use correlations to predict temperature rise and velocity at given radial positions in the ceiling jet. However, few studies focus on the vertical distribution within the ceiling jet that flows under an inclined ceiling. A series of pool fire tests was conducted using a flat, unconfined model ceiling with a changing ceiling inclination angle of up to 40°. Temperature distributions were obtained using a rake of 0.2 mm diameter chromelalumel thermocouples. Velocity distributions were also obtained using particle image velocimetry. The ceiling jet thickness was defined as the distance from the ceiling surface to the position that was 1/e of the maximum values. The maximum velocity and temperature rise variations were compared against the inclination angle. The relationship between Gaussian momentum and thermal thickness and the ceiling inclination angel were also examined.

Keywords: Ceiling jet, Unconfined inclined ceiling, Momentum and temperature thickness, Gaussian momentum and thermal thickness.

© 2011 CPD Unit, University of Leeds