Saturday, September 22, 2012

Tutorial: Fuel Tank Sloshing

Introduction
The purpose of this tutorial is to investigate the free surface movement of liquid fuel in a tank under varying acceleration scenarios and to determine the most suitable configuration of the fuel tank to ensure continuous fuel supply through the pick-up pipe Two con configuration of the fuel tank are considered|tank with internal baffles and tank without internal baffles. You will compare the two configuration on the basis of liquid interface and velocity vector plots generated for each case.This tutorial demonstrates how to do the following Set up and solve a transient problem using the pressure-based solver and the VOF model Define parameters specific to the Non-Iterative Time Advancement (NITA) scheme Create a journal file to track the liquid interface with time Request automatic execution of commands to create images for post-processing Compare the two configuration on the basis of liquid interface and velocity vector plots generated.


Problem Description
The tutorial considers two configuration of the fuel tank for comparison. Figure 1 shows the tank with internal baffles. Figure 2 shows the tank without baffles. The tank undergoes an acceleration of 9.81 m/s2 in the positive X direction. Recall that if the tank accelerates in the +X direction, the liquid experiences an equal and opposite reaction in the -X direction. After 1.5 seconds, the acceleration in the X direction stops and only gravity (in the -Z direction) acts on the liquid in the tank A prior analysis indicates that the pick-up pipe might not be completely submerged after 0.45 seconds of acceleration and after 1.25 seconds of acceleration. An analysis of both tank designs will be compared after 0.45 seconds and 1.25 seconds to con rm that the pickup pipe in the tank without baffles is not submerged in fuel while the tank with baffles will be analyzed to see if the baffles x the problem and keep the pick-up pipe completely submerged in fuel. The tank with baffles will be analyzed first. Then, the baffles will be switched from wall boundaries to interior boundaries and the tank without baffles will be analyzed under the same conditions as the tank with baffles.






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