Ramjet engine with rotating detonation combustion system and method for operation

A ramjet engine, the ramjet engine comprising:

• a longitudinal wall extended along a lengthwise direction, wherein the longitudinal wall defines an inlet section, a combustion section, and an exhaust section;
• a centerbody defined radially inward of the longitudinal wall;
• a gas flowpath defined by the longitudinal wall;
• and
• a convergent-divergent nozzle at the combustion section, the convergent-divergent nozzle including:
• a first fuel nozzle assembly extended from the longitudinal wall into the gas flowpath;
• and
• a second fuel nozzle assembly extended from the centerbody into the gas flowpath, wherein the first fuel nozzle assembly and the second fuel nozzle assembly together define a nozzle throat area of a rotating detonation combustion system,
• wherein each of the first fuel nozzle assembly and the second fuel nozzle assembly comprising:
• (a) a first wall converging inward toward the nozzle throat area;
• (b) a second wall diverging outward from the nozzle throat area;
• and
• (c) a fuel injection port positioned at the nozzle throat area in a wall connecting the first wall to the second wall,
• wherein the first fuel nozzle assembly and the second fuel nozzle assembly are moveable along a radial direction to adjust the nozzle throat area based at least on a difference in pressure of a flow of fluid at an inlet of the inlet section and a pressure of the flow of fluid at the convergent-divergent nozzle.