Interaction of fire plume with inclined surface

The fire plume interacting with an inclined surface was visualised and analysed using a modified positive-negative grid schlieren system combined with a CCD camera and computer system. The fire source was simulated by a gas burner with a fine perforated burning surface. This produced a fire of 1.0-3.0 kW uniformly across the surface. Isothermal and adiabatic surfaces were constructed as the inclined surface. Sequences of the schlieren images of the fire plumes were taken systematically at various inclination angles from 0 to 40 degrees. The images clearly showed that the fire plumes bent toward the surface. Near the burner, both the flame and the buoyant flow attached to the surface, and there was a point at which the plume detached from the surface and rose at an angle to the surface. Two parameters were measured from the schlieren images to describe the fire plumes features. The first is the length of the fire plume attachment to the surface, the second is the angle between the main stream of the plume and the inclined surface. It was found that the plume attachment length started to increase sharply, when the inclination angle reached 24 degrees. This acceleration in the plume attachment length was used to identify the critical inclination angle. Measurements of the temperature distribution in the fire plume were also carried out using K-type thermocouples. The effects of the surface conditions and of the fire heat release rate on the plume and the critical inclination angle are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.