Andrew HYSLOP, Rowland PENTY GERAETS, Sebastien WYLIE, Jim MERRIFIELD, Matthew McGILVRAY
DOI Number: N/A
Conference number: HiSST-2025-080
The operational modes and self-starting characteristics of a sub-scale, Mach 7, 2D mixed-compression intake were experimentally investigated as a function of imposed back-pressure and isolator height. The experiments were conducted in the University of Oxford High Density Tunnel at a freestream unit Reynolds number of 13.6 x 106 m-1 at a Mach 7 flight representative condition. The self-starting ability of the intake was shown to be highly sensitive to isolator height, with heights below the Kantrowitz limit shown to be not self-starting for this intake configuration. The imposed back-pressure of the intake could be varied by actuating a wedge to change the throttle area at the isolator exit. A sweep of back-
pressure was conducted for two isolator heights (5.9 mm and 7 mm). For each sweep, three modes of operation were identified: started, oscillatory isolator, and buzz. At each operational regime, pressure traces along the intake are shown as well as captured mass flow measurements. The experiments successfully showed that an intake behaviour can be characterised with varying back-pressure and this approach can be extended to more complex intakes in the future.