Rocket injector subscale stability assessment with telescoping throat or moveable injector plate

A subscale rocket injector stability test system comprising:

• a chamber;
• an injector plate spanning across a cross-section of the chamber to provide a barrier at an upstream end of the chamber, the injector plate removably attached to the upstream end of the chamber, and the injector plate structurally holding one or more injectors configured to inject one or more propellants into the chamber, wherein the injector plate is one of a plurality of different injector plates configured to be removably attached to the chamber for interchanging the injector plate with a different injector plate of the plurality of different injector plates, the different injector plate structurally holding one or more different injectors, wherein a single injector plate is configured to be attached to the chamber during testing;
• and
• a telescoping throat positioned at a downstream end of the chamber, wherein the telescoping throat is continuously moveable in an axial direction to continuously vary a combustion volume of the chamber located between the injector plate and an upstream end of the telescoping throat.

A method of subscale testing rocket injector stability, the method comprising:

• injecting into a combustion chamber one or more propellants from one or more injectors supported by a modular injector plate to cause combustion, the modular injector plate being one of a plurality of different injector plates configured to span across a cross-section of the combustion chamber to provide a barrier at an upstream end of the combustion chamber and to be removably attached to the combustion chamber for interchanging the modular injector plate with a different injector plate of the plurality of different injector plates, the different injector plate structurally holding one or more different injectors, wherein a single modular injector plate is attached to the combustion chamber during the injecting;
• continuously varying a combustion volume within the combustion chamber;
• and
• detecting acoustic data from within the combustion volume as the combustion volume is varied.