A scramjet engine has a first passage forming member and a second passage forming member. A passage is formed between a first surface and a second surface. The passage has an upstream zone, a combustion zone and a downstream zone. A cavity of a concave shape is provided on the first surface in the combustion zone. The first passage forming member has a convex section located in the upstream zone, a first fuel injection section configured to inject fuel into the passage from a first fuel nozzle provided for the convex section, and a second fuel injection section configured to inject fuel to the cavity. The second passage forming member has a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided in the downstream zone.

A scramjet engine has a first passage forming member and a second passage forming member. A passage is formed between a first surface and a second surface. The passage has an upstream zone, a combustion zone and a downstream zone. A cavity of a concave shape is provided on the first surface in the combustion zone. The first passage forming member has a convex section located in the upstream zone, a first fuel injection section configured to inject fuel into the passage from a first fuel nozzle provided for the convex section, and a second fuel injection section configured to inject fuel to the cavity. The second passage forming member has a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided in the downstream zone.

A combined cycle propulsion system for a flight vehicle includes a compressor-fed combustion engine, and a multi-mode supersonic engine. The multi-mode supersonic engine includes an adjustable inlet section, a combustion section arranged downstream of the adjustable inlet section and including a first combustor portion having at least one rotating detonation combustor and a second combustor portion having a supersonic combustion type combustor, and an adjustable exhaust nozzle section arranged downstream of the combustion section. The at least one rotating detonation combustor functions as a pilot for the supersonic combustion type combustor.

A combined cycle propulsion system for a flight vehicle includes a compressor-fed combustion engine, and a multi-mode supersonic engine. The multi-mode supersonic engine includes an adjustable inlet section, a combustion section arranged downstream of the adjustable inlet section and including a first combustor portion having at least one rotating detonation combustor and a second combustor portion having a supersonic combustion type combustor, and an adjustable exhaust nozzle section arranged downstream of the combustion section. The at least one rotating detonation combustor functions as a pilot for the supersonic combustion type combustor.

A scramjet engine with a novel isolator is disclosed herein. The scramjet includes an air inlet configured to receive and direct air into the engine and a combustor operable to receive air from the air inlet and combust fuel therein as is conventional. An isolator is positioned between the air inlet and the combustor. The isolator includes a primary flow path separated into a plurality of separate secondary flow channels formed therethrough. The smaller secondary flow channels prevent shockwaves from propagating upstream from the combustor to the inlet that can occur during some operating conditions of a supersonic combustion flow process.

A scramjet engine with a novel isolator is disclosed herein. The scramjet includes an air inlet configured to receive and direct air into the engine and a combustor operable to receive air from the air inlet and combust fuel therein as is conventional. An isolator is positioned between the air inlet and the combustor. The isolator includes a primary flow path separated into a plurality of separate secondary flow channels formed therethrough. The smaller secondary flow channels prevent shockwaves from propagating upstream from the combustor to the inlet that can occur during some operating conditions of a supersonic combustion flow process.

Provided herein is a fuel injector capable of providing fuel into a jet engine operating at hypersonic speeds. Embodiments may include a system for fuel injection for an engine traveling at supersonic speeds. The system may include a fuel injection strut extending between opposing walls of an inlet to the engine, and a porous surface extending across at least a portion of the fuel injection strut. The fuel may be introduced into the inlet of the engine through the porous surface of the fuel injection strut. The porous surface of the fuel injection strut may extend along a fuel injecting portion of the fuel injection strut spaced a predefined distance from the opposing walls of the inlet. The porous portion of the fuel injection strut may include a porosity of about 100 pores per square inch or lower porosities as dictated by the specific design considerations.

Provided herein is a fuel injector capable of providing fuel into a jet engine operating at hypersonic speeds. Embodiments may include a system for fuel injection for an engine traveling at supersonic speeds. The system may include a fuel injection strut extending between opposing walls of an inlet to the engine, and a porous surface extending across at least a portion of the fuel injection strut. The fuel may be introduced into the inlet of the engine through the porous surface of the fuel injection strut. The porous surface of the fuel injection strut may extend along a fuel injecting portion of the fuel injection strut spaced a predefined distance from the opposing walls of the inlet. The porous portion of the fuel injection strut may include a porosity of about 100 pores per square inch or lower porosities as dictated by the specific design considerations.

A dual mode ramjet or scramjet engine used in the propulsion of an aircraft includes an inlet configured to receive and compress air, a combustion chamber connected to the inlet and configured to mix the compressed air with fuel to pressurize the dual mode ramjet or scramjet engine, and an acoustic attenuator having one or more resonator cavities integrated into the combustion chamber.

A dual mode ramjet or scramjet engine used in the propulsion of an aircraft includes an inlet configured to receive and compress air, a combustion chamber connected to the inlet and configured to mix the compressed air with fuel to pressurize the dual mode ramjet or scramjet engine, and an acoustic attenuator having one or more resonator cavities integrated into the combustion chamber.