Performance Evaluation of an Engine-Integrated & Bleed-Air-Driven Thermal Management System in Fighter Aircraft

Abstract

The increasing heat loads of modern supersonic fighter aircraft demand advanced thermal management solutions. This presentation introduced an engine-integrated thermal management system based on a bleed-air-driven open reverse Brayton cycle that rejects heat into the engine bypass flow. The interaction between system cooling performance and engine operation was discussed using a representative fighter configuration developed at the German Aerospace Center. Further the modeling of the TMS heat exchangers was presented in detail. The focus of the TMS performance analysis was on the influence of the compressor pressure ratio and on system behavior under steady operating conditions as well as throughout a flight mission. The results showed that there is no clear design optimum for the TMS compressor pressure ratio. Higher design pressure ratios improve TMS cooling capacity only under high engine load conditions and do not provide overall mission benefits, while increasing fuel consumption. The findings illustrate the performance limitations of a simple reverse Brayton cycle and underline the importance of advanced off-design operation strategies.