Reduced Pressure Effect on The Centerline Plume Temperatures of Elevated n-Heptane Fires in an Aircraft Cargo Compartment

Abstract

ABSTRACT This paper investigates the influence of the reduced pressure on the temperature profile of the weak and strong fire plumes by elevating n-Heptane fires. A series of elevated n-Heptane fire tests were conducted in a full-scale simulated Boeing 737–700 aircraft cargo compartment at 70 kPa, 80 kPa, 90 kPa and 100 kPa. The experimental results show that both the centerline temperature rise and the maximum ceiling temperature rise of weak and strong plumes at reduced pressures can be represented in three-region law similar to McCaffrey plume model. Thereinto, the weak plume temperature increases with the decrease of the atmosphere pressure owing to the low air entrainment, while the strong plume temperature in the continuous flame region decreases at reduced pressure, because the hot thermal flow of the strong plume impinges the ceiling violently causing the more air entrainment. The maximum ceiling temperature at the reduced pressure changes as similar with the centerline temperature driven by strong plumes. By introducing the reduced pressure coefficients, new correlations for predicting the centerline temperature and maximum ceiling temperature induced by weak and strong plumes are proposed with wider application range.