ROCKET INJECTOR SUBSCALE STABILITY ASSESSMENT WITH TELESCOPING PISTON

Systems and methods for subscale testing of rocket engine injector stability. The system includes a combustion chamber and a piston within the chamber that is continuously axially moveable via an actuator. An annular gap between the piston and a chamber sidewall provides a minimal cross-sectional flow area. A modular injector plate comprises one or more injector elements configured to inject a fuel and an oxidizer into the chamber. The piston is continuously translated, to thereby continuously vary a combustion volume of the chamber and to create a dynamically tunable downstream boundary. The injector elements are thus exposed to acoustic modes of varying frequency, covering the range of acoustic modes expected in a full scale rocket engine. The injector plate is removably attached to an upstream end of the chamber for replacement of the first injector elements with different, second injector elements for subsequent testing.