Hybrid-Cycle Power and Thermal Management System (PTMS)

Added: Jul 31, 2015 2:31 pm Next generation fighter aircraft are likely to require an unprecedented level of advanced capabilities in order to ensure air superiority in contested environments. These capabilities, which include advanced electronic attack, high-power laser, and future low-observability features, are expected to require as much as 10x higher power levels than current tactical systems. While these power system demands are significant, thermal management of these advanced systems may present a larger concern as component efficiencies and waste heat qualities are low. Modern vehicle design factors including composite aircraft skins, higher efficiency engines, and highly embedded vehicle systems compound these challenges. Further, the duty cycles of these loads can be rather varied from continuous to less than 5% of mission duration requiring wide thermal management system (TMS) full-range to nominal operational levels. Conventional air cycle systems (ACS) offer the advantages of higher temperature lifts over comparable vapor cycle systems (VCS). However, VCS are generally 10x more efficient at moving heat, resulting in reduced heat rejection demands on vehicle thermal sinks. VCS also reduce prime power requirements, typically in the form of shaft power extraction which is more efficiently supported by the engine cycle than the bleed air driven ACS. Additionally, storage in the form of chilled fuel or other thermal energy storage mechanisms can also be used to reduce the system maximum performance requirement. As such, hybrid approaches which attempt to capitalize on the benefits of various thermal cycles while minimizing their detriments may offer significant promise for these challenging applications. Further, all potential thermal sinks including engine burn-fuel, fan bypass air, third stream air, ram-air or ACM-generated sinks may not be available over the full range of aircraft operation. The ability to selectively use available heat sinks in the most optimal way to ensure sufficient and efficient cooling over the entire vehicle flight regime is a desired capability.