Apparatuses, systems, and methods for optimizing acoustic wave confinement to increase combustion efficiency

A system comprising:

• an apparatus selected from a rocket engine, an air breathing combustion engine, a gas generator, a preburner, and a power generator;
• wherein the apparatus comprises a combustion chamber having:
• an injector coupled to a head portion of a combustion chamber, the injector comprising a plurality of injector elements distributed away from an inner annulus and in an outer annulus;
• wherein a geometry of combustion chamber comprises a body portion, an optional shoulder portion, and a throat;
• wherein an inner wall of combustion chamber converges radially inward towards the throat;
• and
• wherein the plurality of injector elements in combination with the geometry of the combustion chamber are configured to confine a predetermined percentage of the mass flow associated with combustion to a predetermined outer annulus of the chamber.

A method for increasing combustion efficiency, the method comprising:

• determining a geometry for the combustion chamber to increase coupling between unsteady acoustic wave and combustion;
• determining injection configuration parameters for a combustion chamber the injection configuration parameters selected from propellant type, number of fuel injector ports, number of injector ports per injector element, direction of injector ports, placement of the injector elements within an outer radius mass flow range, and combinations thereof;
• and
• configuring one or more limiting devices to reduce unwanted acoustic modes.