Rotorcraft Engine Cycle Optimization at Mission Level

Abstract

This work investigates the potential to reduce fuel consumption associated with civil rotorcraft operations at mission level, through optimization of the engine design point cycle parameters. An integrated simulation framework, comprising models applicable to rotorcraft flight dynamics, rotor blade aeroelasticity, and gas turbine performance, has been deployed. A comprehensive and computationally efficient optimization strategy, utilizing a novel particleswarm method, has been structured. The developed methodology has been applied on a twinengine light and a twinengine medium rotorcraft configuration. The potential reduction in fuel consumption has been evaluated in the context of designated missions, representative of modern rotorcraft operations. Optimal engine design point cycle parameters, in terms of total mission fuel consumption, have been obtained. Pareto front models have been structured, describing the optimum interrelationship between maximum shaft power and mission fuel consumption. The acquired results suggest that, with respect to technological limitations, mission fuel economy can be improved with the deployment of design specifications leading to increased thermal efficiency, while simultaneously catering for sufficient performance to satisfy airworthiness certification requirements. The developed methodology enables the identification of optimum engine design specifications using a single design criterion; the respective tradeoff between fuel economy and payload–range capacity, through maximum contingency shaft power, that the designer is prepared to accept.