Search Results

The thermal management of modern aircraft has become more challenging as aircraft capabilities have increased. The use of thermally resistant composite skins and the desire for low observability, reduced ram inlet size and number, have reduced the ability to transfer heat generated by the aircraft to the environment. As the ability to remove heat from modern aircraft has decreased, the heat loads associated with the aircraft have increased. Early in the aircraft design cycle uncertainty exists in both aircraft requirements and simulation predictions. In order to mitigate the uncertainty, it is advantageous to design thermal management systems that are insensitive to design cycle uncertainty. The risk associated with design uncertainty can be reduced through robust optimization. In the robust optimization of the thermal management system, three noise factors were selected: 1) engine fan air temperature, 2) avionics thermal load, and 3) engine thrust.

Next generation aircraft will require more electrical power, more thermal cooling, and better versatility. To attain these improvements, technologies will need to be integrated and optimized at a system-level. The complexity of these integrated systems will require considerable analysis. In order to characterize and understand the implications of highly-integrated aircraft systems, the effects of pulsed-power, highly-transient loads, and the technologies that drive system-stability and behavior, an approach will be taken utilizing integrated modeling and simulation with hardware-in-the-loop (HIL). Such experiments can save time and cost and increase the general understanding of electrical and thermal phenomena as it pertains to aircraft systems before completing an integrated ground demonstration. As a first step toward completing an integrated analysis, a dynamometer “drive stand” was characterized to assess its performance.

In this paper, a MATLAB-Simulink based general co-simulation approach is presented which supports multi-resolution simulation of distributed models in an integrated architecture. This approach was applied to simulating aircraft thermal performance in our Vehicle Systems Model Integration (VSMI) framework. A representative advanced aircraft thermal management system consisting of an engine, engine fuel thermal management system, aircraft fuel thermal management system and a power and thermal management system was used to evaluate the advantages and tradeoffs in using a co-simulation approach to system integration modeling. For a system constituting of multiple interacting sub-systems, an integrated model architecture can rapidly, and cost effectively address technology insertions and system evaluations. Utilizing standalone sub-system models with table-based boundary conditions often fails to effectively capture dynamic subsystem interactions that occurs in an integrated system.