Sloshing Analysis of a Supersonic Fuel Tank of an Aircraft

Abstract

This paper presents sloshing analysis of fuel in a supersonic aircraft s fuel tank. Sloshing can be defined as the movement of a fluid inside a moving tank. Sloshing phenomenon is of great significance since it is involved in various fields such as propellant slosh in rockets, aircraft, cargo ships and also the trucks that carry different type of fluids. Sloshing occurs when a fluid containing body suddenly accelerates or decelerates that in turn leads to unnecessary vibrations, flammability, noise and structural failure. To reduce the sloshing effects, anti-slosh baffles are employed in the fuel tanks or any other fluid containing body. Baffles are the obstructions installed inside the fuel tank that absorb the kinetic energy of the waves and reduce the sloshing impact by lowering down the momentum of generated waves. In this research, Volume of Fluid Model has been used for Computational Fluid Dynamics analysis. After the analytical and experimental validation of the model, free surface behavior of sloshed liquid has been analyzed under different operating conditions. For experimental results, a commonly used water tank has been used to track the liquid interface under the application of an external force. Effectiveness of baffles has been studied by calculating the pressure forces on the walls of a fuel tank for both baffled and an un-baffled tank. It has been observed that baffles reduce the pressure forces to almost one tenth in the present case. Reaction forces at the tank mounts have been calculated by carrying out structural analysis of the supersonic fuel tank. Settling time is the time required for the sloshing waves to damp down and the said time for different fill levels and excitation forces has been calculated in the present research. Different cases of acceleration and fuel-fill levels have been taken to study the varying sloshing forces with time. This paper presents a detailed sloshing analysis along with a qualitative and quantitative study that is supported by analytical and experimental results.