Reduced Pressure Effect On The Flame Length Of Elevated N-Heptane Fires In An Aircraft Cargo Compartment

Abstract

ABSTRACT This paper investigates the influence of reduced pressure on flame characteristics of elevated n-heptane fires in an aircraft cargo compartment, including the flame height driven by the weak plume and flame extension length driven by the strong plume, in order to provide theoretical support to the fire detection and surface material design. A series of elevated n-heptane pool fire experiments were carried out in a full-size simulated aircraft cargo compartment at different atmospheric pressures (70 kPa, 80 kPa, 90 kPa, 100 kPa). Results show that the experimental data of flame height and flame extension length at normal pressure agree well with Heskestad and Quintiere & Grove models, however, which cannot predict these flame characteristics of elevated fires. As the fire source elevates gradually, the flame height and flame extension length increase. Then modified flame height and flame extension length models at normal pressure were established by considering the elevated height effect. Furthermore, due to reduced pressure effect on the air entrainment into the fire plume, the flame height and flame extension length increase with the decreasing pressure. New flame height and flame extension length correlations applicable to the reduced pressure conditions were proposed by introducing a reduced pressure coefficient and modified nondimensional heat release rates.