Date of Award

2013

Document Type

Thesis

First Advisor

Kizito, Dr. John P.

Abstract

The goal of the current research is to study the dynamics of water in fuel tanks during flight maneuvers. The study was motivated by the fact that airplane fuel tanks can be exposed to extremely low temperatures, whereby water can nucleate and freeze, in turn causing the fuel lines to clog. Therefore, ice formation in the fuel system may lead to aviation safety issues. Different scenarios were considered which influence the movement of water and kerosene in a fuel tank. A test rig was constructed to replicate airplane motions when taking off, landing, and turning. Computer-simulated experiments were performed to replicate airplane motions under roll maneuvers and when turning right or left. The computer model required the a priori knowledge of interfacial properties of water in kerosene. These properties were experimentally measured and were used as input data for the computer simulation. The surface tension of water was confirmed as 72.9 mN/m, and the surface tension of water in kerosene (the interfacial tension between kerosene and water) was measured as 6.78 mN/m. The contact angle of water in kerosene on aluminum and plexiglass was measured as 114.9º and 121.1º, respectively. The contact angle of water in the air on aluminum and plexiglass was measured to be 49.6º and 64.6º, respectively. The experimental simulations showed that water took 114.9 seconds to clear the fuel line port while the tank was in a takeoff mode, compared to 121.8 seconds while the tank was in landing mode. The time taken for water to clear the fuel line decreased before it increased when the tank inclination was changed from 0 to 30º. In addition, the volume of water remaining in the fuel tank decreased as the tilt angle was increased. The computer-simulated experiments were performed for an airplane undergoing right and left banking motion in addition to roll motions. The results showed that the resultant acceleration vector and magnitude had a significant influence on the local composition and movement of water in the fuel tank.

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