Multidisciplinary optimization in conceptual design of mixed-stream turbofan engines

Conceptual engine design is currently done essentially using a trial-and-er ror process based on the experience of engineers. This paper presents an al ternative approach using multidisciplinary optimization to automate the con ceptual design phase and ensure that an optimal design is reached. A robust integrated computer program was created to find the values of eight basic engine parameters that minimized fuel usage over a given mission. Because o f the character of the objective function, a new approach was devised incor porating a genetic algorithm with a switch to a gradient-based algorithm to refine the design. The new procedure was used to optimize the engine desig n for a conceptual short-range interceptor. The process is general, however , and can be applied to a wide variety of missions and aircraft.