Effects of altitude and inclination on the flame structure over the insulation material PS based on heat and mass transfer

Abstract

Experiments were conducted on the insulation materials of EPS and XPS in a small-scale flame spread experimental bench in the Tibetan plateau area of Lhasa (with an altitude of 3658m) and the plain area of Hefei (with an altitude of 50m), respectively. The detailed flame structure including flame angle, flame length and maximum length of pool fire over EPS and XPS with thicknesses of 2cm, 3cm, 4cm and 5cm inclined at the angles of −30° to 30° was investigated. It is found that for the same thickness of EPS and XPS inclined at the same angle, the flame length is longer and the flame angle is smaller in Hefei than those in Lhasa in the wall fire zone, which is in good agreement with the predictions. The preheating length δf is correspondingly longer in plain due to smaller flame angle and longer flame length and the flame heat flux q̇f″ increases with air pressure, which make the flame convective and radiative heat (q̇f″)2δf larger leading to promote flame spread. For the horizontal flame spread over EPS and XPS, the maximum length of pool fire is significantly smaller than that in other incline angles in Lhasa, which can be attributed to the smallest heat transfer to the residue pool fire zone during flame spread making PS in the residue pool fire zone extinguish more easily.