Inversely Designed Scramjet Flow-Path

It can be argued that at the heart of functional hypersonic vehicle/platform is its engine/scramjet. Key to a functionally efficient scramjet engine lies in the design of its flow-path. The flow-path can be thought of as consisting of the following distinct sections: (1) the forebody inlet section; (2) the isolator section, (3) the combustor section, and (4) the nozzle section. In this chapter the focus will lie in the design on the forebody inlet and the isolator sections. This flow-path design must take into account an extremely complex flow-field physics and the interaction of physical surfaces with this complex flow-field. Many attempts to design efficient scramjet flow-paths have met with some measured degree of success in achieving the desired outcome. The approach that will be presented is an ‘inverse design’ approach. In a similar manner to Darwin’s theory of evolution, where an organism adopts to survive in its environment; the scramjet flow-path will be carved/extracted from the operational environment. The objective of this design approach is to naturally and organically capture, process and direct the flow from the environment; thus preparing it for the combustion process. This approach has its origin in the ideal 2-D oblique shock relations, coupled with Nonweiler’s caret waverider theory and streamline marching techniques.Keywords: Scramjet Flow-Path, Hypersonic Propulsion, Inverse Design, Stream Tube, Oblique Shockwave, Billig’s Isolator Relations, Nonweiler’s caret waverider