Experimental study of an aircraft fuel tank inerting system

Abstract

In this work, a simulated aircraft fuel tank inerting system has been successfully established based on a model tank.Experiments were conducted to investigate the influences of different operating parameters on the inerting effectiveness of the system, including flow rate of the inert gas (nitrogen-enriched air), inert gas concentration, fuel load of the tank and different inerting approaches. The experimental results show that under the same operating conditions, the time span of a complete inerting process decreased as the flow rate of inert gas was increased; the time span using the inert gas with 5% oxygen concentration was much longer than that using pure nitrogen; when the fuel tank was inerted using the ullage washing approach, the time span increased as the fuel load was decreased; the ullage washing approach showed the best inerting performance when the time span of a complete inerting process was the evaluation criterion, but when the decrease of dissolved oxygen concentration in the fuel was also considered to characterize the inerting effectiveness, the approach of ullage washing and fuel scrubbing at the same time was the most effective.

Avionics Compartment Fire Extinguishing on the Commercial Airplanes

“…The experiment had limitation due to difficulties in building a typical aircraft avionics compartment bay with racks and computers. The theoretical and practical achievement of this research can certainly be considered as an important milestone in the road-map to perform more research in future [13].…”

Oxidation of n-hexane in the vicinity of the auto-ignition temperature

“…In 2008, the Federal Aviation Administration published the Fuel Tank Flammability Reduction Rule [13] requiring the installation of a flammability reduction or ignition reductions means for the fuel tanks that are most at risk. A number of inerting strategies can potentially be employed to reduce or eliminate the risk of accidental explosion in the fuel tanks of aircraft [14,15,16]. In the framework of aircraft safety, the term "inert mixture/environment" designates a non-flammable or non-explosive mixture, not necessarily a mixture in which no reaction is taking place.…”

“…The applicability of this effective approach to commercial aircraft is limited due to the reduction of the volume available for fuel, an increased weight of the fuel tank, maintenance complication, and limited life-time. There are a number of other possible strategies, such as inerting with liquid nitrogen and inerting with halon, that have been examined [14,15,16] but the most practical one that is in use today is on-board inert gas generation system (OBIGGS). The OBIGGS is based on a hollow fiber membrane that exhibits selective permeability so that a nitrogen-enriched environment is created in the fuel tank [15].…”

“…There are a number of other possible strategies, such as inerting with liquid nitrogen and inerting with halon, that have been examined [14,15,16] but the most practical one that is in use today is on-board inert gas generation system (OBIGGS). The OBIGGS is based on a hollow fiber membrane that exhibits selective permeability so that a nitrogen-enriched environment is created in the fuel tank [15]. The nitrogen-enriched stream may be employed to "wash" the fuel ullage to eliminate the gas-phase oxygen and/or to "scrub" the liquid fuel to eliminate the dissolved oxygen.…”

“…The nitrogen-enriched stream may be employed to "wash" the fuel ullage to eliminate the gas-phase oxygen and/or to "scrub" the liquid fuel to eliminate the dissolved oxygen. Extensive studies have been carried out [15,17] to assess the effect of various parameters of the OBIGGS technique including the flow rate of the inert gas, the concentration of oxygen in the nitrogen-enriched stream, and the fuel mass loading of the tank.…”