Physics-based, Fast-Running Tool for Fuel Spurt Modeling from HRAM

ABSTRACT: In Phase I, CFDRC in partnership with ESI, have developed and validated a physics-based CFD tool to quantify fuel spurt caused by impact and penetration of fuel tanks. CFD tool development, qualification and validation study showed good correlations with experiments in terms of fundamental physics including: a) droplet formation, breakup, size, timing and distribution; b) cavitation zone and its growth behind a projectile; c) cavitation bubble collapse and associated pressure shock; e) fluid-structure interaction of cavitation with a flexible fuel tank and f) reduced-order module (ROM) development and predictions for fast running. The Phase II objective is to further qualify and validate the high-fidelity physics-based CFD tool under different tank and impact parameters to build knowledge, database and correlations of fuel spurt quantities as a function of a) aircraft fuel properties, such as temperature, depth, ullage pressure, and dissolved gas volume; b) tank parameters, such as dimensions, material and thickness, and internal stiffening structure and cluttering; and c) impact parameters, such as projectile type, impact angle, velocity and location. The generated high-fidelity database will be integrated into a ROM solver, which uses physics-based Ordinary Differential Equation solutions to describe the fuel spurt process. The ROM solver will accurately estimate fuel characteristics in a few minutes of CPU time. The final module will be integrated into the Air Forces analysis environment Fire Prediction Model (FPM).; BENEFIT: The successful completion of this SBIR will provide the Air Force and DoD and their contractors with the capability for rapidly evaluating fire ignition in complicated aircraft (and other vehicle) dry-bays and compartments under various HRAM scenarios. Although most past efforts have been aimed at protecting military aircraft, the developed tool also finds many applications in commercial aircraft, which are at risk due to high velocity fragments produced by engine failure, or even runway debris as in the case of Concorde 203 F-BTSC that crashed after takeoff from Paris. Another application is in the vulnerability assessment of Space Launch Systems under development at NASA, which uses cryogenic liquid fuel. The fast-running module and high-fidelity code can be commercialized for applications in all commercial and military air, ground, and sea vehicles that have fluid-filled fuel tanks.