Aircraft Power System Options and Thermal Management for High, Pulsed Power Application

Abstract

A general thermodynamic analytical evaluation tool was developed to investigate the impact of technological improvements on mission effectiveness and weapon power generation in an aircraft based pulsed power system. The power system investigated consists of six major components, the prime power source, the power generator, the power conditioner, the pulsed power source, the pulsed power processor and the thermal management with a total estimated payload restriction of 4600 kgs. based on a USAF cargo aircraft. The analysis was based on a 2.5 MW pulsed power source output and a notional mission profile with an engagement period of 60 minutes during which several duty cycle scenarios were considered. Six power system architectures were evaluated with a baseline power system model that incorporated current off-the-shelf technologies for each component. A helicopter engine was used as the primary power source because of its high power density but the engine performance is very sensitive to increasing altitude where the output power diminishes rapidly. As a result of this and the necessity to accommodate load-following during engagement, the investigations were extended to a hybrid power system architecture with turboalternator-battery and turboalternator-flywheel combinations. Preliminary analysis based on prorated values of specific power and power density for all the components revealed that the overall mass of the power system could be brought down from 13,330 kgs. for the baseline architecture to 4075 kgs. for the conceptual load-following turboalternator-battery hybrid power system. Coolant requirements for an open thermal management system ranged from 2007 kgs. of Ammonia or 1127 kgs. of water for a heat load of 2.9 Mwt corresponding to a 30% duty cycle pulsed power source operation.