Rocket nozzle for a rocket engine

A rocket engine of the type having rocket nozzle structure which has a flowpath for rocket gases extending axially through the nozzle, the nozzle structure including a casing which bounds the flowpath, the casing having a throat and a divergent region extending downstream from the throat, the divergent region having a high expansion ratio and the nozzle having a full flow region and a separated flow region under at least one operative condition of the the engine, wherein the improvement comprises:

• a casing having a divergent region which bounds the flowpath for rocket gases, the casing including,
• an inner wall having a plurality of openings in flow communication with the flowpath for rocket gases;
• an outer wall spaced outwardly from the inner wall leaving a cavity therebetween, the outer wall having at least one first opening and at least one second opening which are in flow communication with the cavity,
• divider means extending between the inner wall and the outer wall to divide the cavity into a first manifold and a second manifold, two manifolds being axially adjacent one to the other and extending circumferentially about the casing between the inner wall and the outer wall,
• a plurality of vent passages, at least one of which at the first manifold extends from the exterior of the casing through the first opening in the outer wall, through the first manifold, and through an opening in the inner wall to the interior of the casing, and at least one of which at the second manifold extends from the exterior of the casing through the second opening in the outer wall, through the second manifold, and through an opening in the inner wall to the interior of the casing;
• and,
• means for placing each vent passage in flow communication with the exterior and with the interior to allow flow through the vent passage from the exterior to the interior and for blocking flow from the interior to the exterior, the means being responsive to the total pressure of the interior of the nozzle and the pressure at the exterior of the nozzle;
• wherein the means permits flow through vent passages from the exterior to the interior into the associated manifold to distribute pressurized gases along an axial length of the casing adjacent the separated flow region and blocks flow through vent passages from the interior to the exterior in full flow regions of the nozzle.