EFFECTS OF VARIOUS BAFFLE DESIGNS ON CENTER OF GRAVITY DEVIATION IN A TRAINING AIRCRAFT WING FUEL TANK USING 1D SIMULATIONS

There are baffle components in aircraft fuel tanks to damp sloshing effects and prevent Center of Gravity (CoG) traveling from its initial location. These baffles have significant role in damping forces, moments acting on aircraft body and CoG deviation. Ribbed baffles have cutout holes on its surface as design details. These cutout holes directly affect CoG deviation amount and retreat duration of deviated CoG in the tank. In this study, various cutout designs and aircraft wing tank geometries were modeled with Siemens NX CAD modeling program. These various designs were used in 1D and transient CFD sloshing analyses, then effects of different designs were investigated.1D analyses were constructed using Siemens Amesim program and they were managed in order to get initial conditions for further CFD analyses. As an input, bank-to-bank maneuver acceleration was applied along 10 seconds on aircraft body with 45° roll angle. At the end of acceleration, simulations were conducted until steady conditions were met in order to get retreat duration. The aim of the 1D analyses was to achieve minimum deviation amount and minimum retreat duration that will be assumed to be the most desirable case. Transient 3D CFD analyses have been performed with Siemens StarCCM+ in order to obtain most realistic solutions. For the optimum cases, CFD simulations were conducted using multi-phase sloshing flow of jet fuel (JP8) and air using Volume of Fluid (VOF) method. Thus, much detailed information about CoG deviation, retreat duration, sloshing effects of free surface fluctuations and 3D turbulent eddies became observable from CFD simulations. As a result, optimum performance efficiency of baffles was considered as lower CoG deviation distance and shorter retreat duration.