This presentation was made at CAASE18, The Conference on Advancing Analysis & Simulation in Engineering. CAASE18 brought together the leading visionaries, developers, and practitioners of CAE-related technologies in an open forum, to share experiences, discuss relevant trends, discover common themes, and explore future issues.

Resource Abstract

Modern military aircraft platforms are using more and more power which results in an ever increasing power density (SWaP). This in turn, generates more heat that has to be dissipated from the instrument panel and cockpit of the aircraft. Complicating this further is that the use of structural composites which are not efficient conductors of heat and the mission requirements of small heat signatures. Therefore alternative means of extracting the heat from the avionics systems must be used. Liquid cooled systems have the advantage over air cooled systems of a much higher heat transfer rate and the fact that the heat can be transported a significant distance from the source. While the idea of liquid cooled avionics is not new, they have gained significant more attention with the latest generation of military aircraft as the only viable method of cooling the systems while maintaining the operational specs of the aircraft.
Liquid cooled avionics have their own challenges as well. The architecture of the components (cold plates, etc) used for extracting the heat from the electronics component must be optimized to perform consistently and reliably while maintaining the smallest footprint possible in the already crowded instrument panel. Additionally, these systems require piping, pumps, valves, heat exchangers and controls as well as a heat sink to send the heat to. In most military applications this is the fuel.
Therefore, the design engineers must consider not only the design of the avionics package with its cooling requirements but also what to do with the heat once it has been transferred to the coolant. This requires the ability to optimize both the component design with the cooling design concurrently.
A proposed method for this concurrent optimization is through the use of characterized 3D CFD simulations from a CAD imbedded CFD software in a system simulation tool using model based design approach. This allows initial evaluations of the cooling system long before the physical components would be available for bench testing.