Optimization of Open Rotor Engines for Civil Aircraft Using a Cooperative Evolutionary Method

An open rotor engine is considered to power a civil transport aircraft; an optimization procedure based on a cooperative evolutionary algorithm, which employs a genetic algorithm, differential evolution and particle swarm optimization in parallel, is used to minimize the aircraft take-off gross weight, given payload, take-off and landing distances, time to climb to cruise altitude, and range. Different performance indexes are also considered for the sake of comparison. The procedure provides the optimal values of wing loading and engine design variables. Modeling capabilities have been developed for assessing this system; off-design analysis is embedded into the optimization code to asses the fulfillment of performance constraints. The benefits of the open rotor architecture in comparison to traditional high bypass turbofans are highlighted. The procedure proved to be fast and reliable. It can be easily modified to perform analysis of alternative innovative engine architectures and to deal with multiobjective optimization.