An improved engine analysis and optimization tool fo hypersonic combined cycle engines

It is widely accepted that more efficient propulsion technology needs to be developed before the re-usable 'space plane' concept for cheap and reliable access to space can become a practical reality. An engineering tool, called the HYbrid PRopulsion Optimiser, or HyPro for short, has been developed to characterise and optimise the performance of a range of hypersonic propulsion systems, with particular application to air-breathing and hybrid engines. The level of modelling embodied in the tool is particularly appropriate to the rapid parametric studies and configurational trade-offs that are usually conducted during the preliminary design of the propulsion system and the hypersonic vehicle that it is intended to propel. An algorithm, based on the Genetic Programming approach, and exploiting the highly modular structure of the engine model, has been developed to search the configurational design space for the engine geometry that is best adapted to the mission for which it is intended. In contrast to conventional optimisers which can vary only the parameters of the engine design, this tool is able to provide design solutions for the propulsion system without the actual structure of the engine having been specified a priori. Several applications serve to demonstrate the value of the tool in introducing some degree of objectivity into the process of discriminating between the many different configurations that have been proposed for space plane propulsion in the past.