Edward Alyanak (Committee Member), Rory Roberts (Advisor), Scott Thomas (Committee Member), Mitch Wolff (Advisor)
Master of Science in Mechanical Engineering (MSME)
Many advances in technology are expected to increase the capabilities of next generation aircraft, and these advances will increase the thermal load on the aircraft as well. In order to assess and account for these increased thermal loads, three studies were performed: a fuel pump trade study, a high energy pulsed system (HEPS) implementation study, and a legacy vehicle environmental control system (ECS) study. The fuel pump study addresses the effect of the implementation of a centrifugal fuel pump versus a variable displacement fuel pump. Traditionally, aircraft designers have used a centrifugal fuel pump over a piston based pump based primarily on mass, volume, cost, and reliability. This study considers specific excess power (SEP), fuel burn and thermal margin and shows the piston based pump performing superior mainly because it eliminates fuel recirculation resulting in an increased thermal margin. This investigation demonstrates the benefit of capturing component level models and thermal concerns in the conceptual design process. Both of these issues are vital to the development of future aircraft designs. Additional research needs to be completed to compare both pumps based on the mass and volume of each system. The second study investigates the implementation of a HEPS device at an air vehicle level. HEPS generate excessive amounts of heat during operation, creating challenges in how to integrate them into an aircraft without overwhelming the vehicle's power and thermal management systems (TMS). In order to evaluate the impact of the HEPS electrical and thermal load on the aircraft's mission, a vehicle level modeling and simulation (M&S) effort must be executed of the power and thermal management systems. To accurately evaluate the total effect on the aircraft, the HEPS must be integrated into a Tip to Tail (T2T) model of the system that includes the aircraft power and thermal management subsystems. With the HEPS system integrated into the T2T model, not only can its mass and volume effects be analyzed, but also the transient power and thermal loads created by the new system can be evaluated for their effect on other aircraft subsystems. Furthermore, the aircraft subsystems can be optimized to vehicle level metrics instead of subsystem level only. This will result in a more effective and balanced overall aircraft design. Using a T2T model to evaluate the integration of a HEPS system on an aircraft will enable assessment of its overall impact to next generation aircraft. Therefore, the significant impact of highly dynamic power and thermal loads on next generation aircraft is addressed. The third study is the implementation of an air cycle based ECS in a legacy (4th generation) air vehicle. Relatively few attempts have been made to define appropriate validation testing constructs for T2T analysis in a transient mode of operation. Current research addresses the process of validation testing using legacy aircraft systems in order to acquire relevant data that will lead to the validation of existing models, and different modeling methods. The model developed in this work will eventually be utilized in these validation efforts at a later date. To this end, an air vehicle system (AVS), turbine engine, generator, and environmental control system (ECS) have been modeled in a T2T model of the actual legacy system. In particular, this study will focus on the creation and integration of the ECS model. The ECS uses an air cycle machine, which utilizes a Brayton refrigeration cycle to cool the air to the cockpit and avionics. The ECS model will be shown to successfully cool these components while subjected to varying bleed rates from the turbine engine.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
Copyright, all rights reserved. My ETD will be available under the "Fair Use" terms of copyright law.