Effects of Inertization Process in Confined Spaces With Application in the Aeronautical Industry

Abstract

A long time ago, you have heard about accidents by gas explosions and the destruction that they can cause. To be able to avoid it requires an understanding of what a gas explosion is and what can reduce the frequency and consequences of these events. The upper and the lower flammability limits (UFL and LFL, respectively) are the maximum and the minimum concentration of the fuel in the air, respectively, in which a flame propagate, they are considered key tools in the prediction of fire, evaluating the possibility of explosion and design of protection systems. There is an interest in finding the flammability limits of ethanol mixed with an inert gas at reduced pressure as a safety measure for the future use of this biofuel in aeronautical applications, taking into account the typical altitude of a commercial aeroplane (<40 000 ft.). In this work, the flammability of hydrated ethanol (5,18%vol. Water) was evaluated experimentally and the nitrogen was used as an inert gas. The experimental bench was build according to the norm ASTM E-681. The ethanol was injected using a precision syringe with 1 ml of volume, nitrogen and air were injected using the partial pressure law of Dalton. The method for measure flammability was by visual observation of flame propagation. The results plotted as a function of the additions of nitrogen shows that when the initial pressure decreases, the UFL decreases and both the LFL and the limit oxygen concentration (LOC) increases. In addition, the variation of UFL is more noticeable than the LFL when the percentage of nitrogen increase in the ethanol/air mixture.