The Direct-Connect Scramjet Isolator is used to study shock-dominated flows inside supersonic dual-mode scramjet isolators, similar to those being developed by the US Air Force. Our current focus is on developing controls algorithms that will help keep the isolator from unstarting when encountering perturbations to the downstream pressure.
The Direct-Connect Scramjet Isolator is being used to develop and validate algorithms developed to enable closed-loop control of ram-mode unstart in scramjet isolators. The facility is designed with the isolator that is a straight rectangular channel of dimensions 26 inches long by 1.5 inches high by 4 inches wide. The isolator is directly connected to a Mach 1.8 nozzle. Nozzles with and without boundary layer distortion can be generated.
(left) Photograph of the Direct-Connect Scramjet Isolator; (right) Schematic showing active control devices.
The facility is equipped with Kulite pressure ports along the top wall and acrylic windows to enable Schlieren visualization. Two actuators enable the back pressure to be modulated in time: (1) a downstream flap, which can oscillate at frequencies as high as 10 Hz, and (2) fast-acting jets that issue from the top wall (fed by the yellow hoses in the photo) can actuate with bandwidths of about 100 Hz.