Engine with rotating detonation combustion system

1. An engine, the engine comprising:

a longitudinal wall extended along a lengthwise direction, wherein the longitudinal wall defines a gas flowpath and a combustion section;

an inner wall assembly extendable from the longitudinal wall into the gas flowpath, wherein the inner wall assembly includes an upstream face and defines an adjustable rotating detonation combustion region at the upstream face in the gas flowpath adjacent to the longitudinal wall, and wherein the inner wall assembly is extendable into the gas flowpath to adjust a depth of the rotating detonation combustion region in correspondence with an adjustable depth of the upstream face;

an actuator coupled to the inner wall assembly, wherein the actuator is configured to actuate the inner wall assembly along a depth of the gas flowpath perpendicular to a direction of an oxidizer flowing through the combustion section to adjust the depth of the adjustable rotating detonation combustion region via adjusting the depth of the upstream face of the inner wall assembly; and

wherein the engine is configured to perform operations comprising;

flowing the oxidizer through the gas flowpath into the combustion section, wherein the flow of the oxidizer includes a first portion and a second portion;

capturing, via the inner wall assembly being extended the depth into the gas flowpath by the actuator, the first portion of the flow of the oxidizer at the adjustable rotating detonation combustion region;

flowing a first flow of fuel to the first portion of the flow of the oxidizer captured at the adjustable rotating detonation combustion region via the inner wall assembly;

producing, via a first mixture of the first flow of fuel and the first portion of the oxidizer at the adjustable rotating detonation combustion region, a rotating detonation wave of detonation gases; and

burning a second mixture comprising at least a portion of the detonation gases, a second flow of fuel, and the second portion of the flow of the oxidizer, wherein burning the second mixture is downstream of the rotating detonation wave of detonation gases.

2. The engine of claim 1 , the operations comprising:

adjusting, via the actuator, the inner wall assembly to between 0% and 35% of the depth of the gas flowpath.

3. The engine of claim 1 , wherein the inner wall assembly comprises:

a downstream face extended from the longitudinal wall and coupled to the upstream face, wherein the downstream face is disposed at an angle relative to the longitudinal wall.

4. The engine of claim 3 , wherein the longitudinal wall or the upstream face of the inner wall assembly comprises a first fuel injection port, the first fuel injection port configured to provide the first flow of fuel to the adjustable rotating detonation combustion region.

5. The engine of claim 3 , wherein the downstream face of the inner wall assembly comprises a second fuel injection port, the second fuel injection port configured to provide the second flow of fuel downstream of the adjustable rotating detonation combustion region relative to the flow of oxidizer through the gas flowpath.

6. The engine of claim 3 , the operations comprising:

adjusting an angle of the downstream face relative to the longitudinal wall between 10 degrees and 80 degrees relative to the longitudinal wall.

7. The engine of claim 1 , the operations comprising:

adjusting a cross-sectional area of the gas flowpath based on an operating condition of the engine.

8. The engine of claim 7 , wherein adjusting the cross-sectional area of the gas flowpath comprises:

adjusting, via the actuator, the depth of the inner wall assembly along the depth of the gas flowpath based at least on the operating condition of the engine.

9. The engine of claim 1 , wherein the combustion section comprises:

a deflagrative combustion process downstream of the detonation combustion region relative to the flow of oxidizer in the gas flowpath.