Design and Test of a Modular Waverider Hypersonic Intake

*† A study of some modular stream-traced hypersonic intakes is presented. These intakes capture a part of a known flowfield by replacing the streamlines that pass through the perimeter of a sector capture shape with solid boundary layer-corrected surfaces. Modules are combined to form an engine with circular external profile and with each intake module feeding a separate combustor. The intakes studied are derived from internally compressive, axisymmetric flowfields with either constant slope or constant pressure boundary conditions. The number of modules varies between three and six. Stream thrust averaging is used to determine equivalent one-dimensional flow for input to a scramjet engine cycle analysis. For a given contraction ratio, the full mass capture engine performance of the modular waverider intakes is comparable with the performance of isentropic spike intake designs when combustor skin friction is neglected. However the low wetted area of the modular combustor design has a significant advantage when combustor skin friction is considered. A four-module waverider intake model was built using stereo lithography and tested at Mach 7 in the University of Oxford gun tunnel, and was shown to be self-starting in QinetiQ’s High Density Tunnel at Mach 7. The stream thrust averaged properties were determined experimentally by measurement of axial force and mass capture. Schlieren photographs and surface pressure measurements are presented. Skin friction in the model isolator section was found to affect intake performance by increasing the amount of compression and reducing efficiency.