Design of a Fuel Thermal Management System for Long Range Air Vehicles

Abstract

The Air Force Research Laboratory (AFRL) has awarded a project contract to Schafer Corporation to conceptualize, design, build, test, and verify a server system capable of allowing remote system integration modeling. To accomplish this, the Distributed Analysis Modeling Environment (DAME) is a system in development for the AFRL Propulsion Directorate Power Division to serve as an integrated modeling environment. To test and verify the server design, it was established that a long range air vehicle system was to be modeled via integration of the various component systems, including an integrated propulsion system comprised of engine, power, thermal management, and fuel subsystems, linked to an air frame model and accessed remotely in order to evaluate trades. This paper will (1) describe the theory, design, and development of the fuel thermal management subsystem, and (2) describe the tools and modeling technique employed to formulate and refine the model and to evaluate the trade studies. Modelogics’ Inc. Model Engineer, a PCbased modeling toolkit that facilitates the building, running, and analysis of custom process and system models, was selected as the software used for modeling the fuel thermal management system. A baseline design environment was established and requirements specific to the fuel thermal management system and environmental control system were defined as the thermal loads and temperature requirements of the system components for each mission segment. Classifying these loads into a hierarchy of component importance relative to thermal load and temperature and as to whether they were air or liquid cooled allowed for the development of the system architecture. Vital component parameters relating to overall system integration were defined which directly linked the fuel thermal management subsystem with the engine and airframe. Understanding that the steady state heat loads over the course of the mission were of critical concern enabled orderly model component placement and a finalized baseline system design. Legacy code and information from the Versatile Affordable Advanced Turbine Engine Thermal Management System Study defined a flight mission to execute and acted as a control comparison for evaluating model generated data and performance as each run was accomplished. Refinement of the model, including varying component properties and mission segment length continued until an entire model run was completed where the final fuel temperature readings remained below the critical temperature level. Trade studies were run to explore a number of alternate thermal management subsystem component arrangements in order to identify the preferred configuration such that, when so equipped, the fully integrated air vehicle system obtained maximum range and performance. This preferred fuel thermal management system architecture was ultimately installed for user access on the DAME server. ∗ Project Engineer, UTC/AFRL/PRTG, Bldg. 490, Rm. 113, 1790 Loop Road North, Wright Patterson AFB, Ohio, 45433-7103, MB 3rd International Energy Conversion Engineering Conference 15 18 August 2005, San Francisco, California AIAA 2005-5647 Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental purposes. All other rights are reserved by the copyright owner.