An intake duct designing method includes: setting a value of a design parameter concerning a design target directed to an aircraft intake duct including a bypass mechanism that suppresses an aerial vibration phenomenon; setting a shape of the design target using the design parameter value; performing computational fluid dynamics analysis including calculating aerodynamic characteristics of the design target and a necessary bypassing flow rate of air released through the bypass mechanism for suppressing the aerial vibration phenomenon, by creating an analytical model for the analysis using the shape of the design target; determining whether an analysis result satisfies a preset design condition; updating the design parameter value when the analysis result is determined as not satisfying the design condition; and repeating the shape setting, the computational fluid dynamics analysis, the determining, and the design parameter value updating, until the analysis result is determined as satisfying the design condition.

A flight vehicle has a propulsion system that includes an air inlet, an isolator (or diffuser) downstream of the air inlet, and a combustor downstream of the isolator. The isolator includes an obstruction that protrudes inwardly from an inner wall of the isolator, into the flow channel in which air flows through the isolator. The obstruction diverts the flow to either side of it. Downstream of the obstruction the flow on either side of the obstruction comes together again, leading to mixing of the flow, for example including mixing of low energy and boundary layer flow with high energy flow. This mixing of flow may make for a more uniform flow at the exit of the isolator. In addition the obstruction may help fix the location of shocks within the isolator, providing longer flow mixing length in the isolator.

A method of operating a gas turbine engine includes generating a flow of combustion products from a gas turbine generator that has a gas generator axis of rotation. A duct is oriented in a first position to direct the flow of combustion products that have passed over at least one gas generator turbine rotor through a fan drive turbine in response to a first desired flight condition. An axis of rotation of the fan drive turbine is transverse to a gas generator axis of rotation. The duct is oriented in a second position to direct the flow of combustion products that have passed over at least one gas generator turbine rotor through an augmentor section in response to a second desired flight condition.

Engine has core compressor, combustor and turbine, fan located upstream of core and supersonic intake for slowing down incoming air at inlet formed by intake, bypass duct surrounding engine core, fan generates airflow to engine core and bypass airflow through bypass duct. Engine has mixer for exhaust gas flow exiting engine core, bypass airflow exiting bypass duct, thrust nozzle for discharging mixed flows, and controller for thrust produced by engine. To change level of engine thrust between transonic push operation and supersonic cruise operation, controller adjusts one or more components which vary relative areas available for hot exhaust gas flow and cold bypass airflow at mixer while holding fan inlet non-dimensional mass flow w {square root over ()} T/P substantially constant, where w is mass flow of incoming air at fan inlet, T is stagnation temperature of incoming air at fan inlet and P is stagnation pressure of incoming air at fan inlet.

A propulsion system includes a main gas turbine engine adapted for generating propulsive thrust during subsonic and supersonic flight operations and a supplementary propulsion unit adapted for generating additional thrust. The supplementary propulsion unit has an air intake and an exhaust for gas accelerated by the supplementary propulsion unit to provide the additional thrust and is adapted to generate the additional thrust during a limited range of subsonic flight operations, and to be dormant during other flight operations. The propulsion system has housing for the supplementary propulsion unit, including intake and exhaust covers which are moveable between deployed and stowed configurations. During the limited range of subsonic flight operations the intake and exhaust cover are moved to the deployed configuration to open the intake and the exhaust. During other flight operations the intake and exhaust cover are moved to the stowed configuration to close the intake and the exhaust.

An inlet for a flight vehicle engine, such as for a supersonic or hypersonic engine, includes an internal flow diverter to divert boundary layer flow. The flow diverter is configured to minimize disruption to flow outside the diverted boundary by being configured through use of a flow field that is also used to configure the walls of the inlet. The flow field that is used to configure an inlet-creating shape and a diverter-creating shape has the same flow generator, contraction ratio, compression ratio, mass capture ratio, pressure ratio between entrance and exit, and/or Mach number, for example. The internal diverter may be configured so as to allow arbitrary selection of a leading edge shape for the internal diverter, for example to use a shape that helps avoid radar detection.

A nozzle wall for an air-breathing engine, the nozzle wall including a first wall surface subject to engine exhaust flow, a nozzle cooling system including at least one heat exchange fluid passage disposed adjacent the first wall surface so as to increase a temperature of a cooling fluid flowing from a fluid reservoir to at least a power extraction device, and the cooling fluid is ejected from the nozzle cooling system downstream from the power extraction device.

Engine has core compressor, combustor and turbine, fan located upstream of core and supersonic intake for slowing down incoming air at inlet formed by intake, bypass duct surrounding engine core, fan generates airflow to engine core and bypass airflow through bypass duct. Engine has mixer for exhaust gas flow exiting engine core, bypass airflow exiting bypass duct, thrust nozzle for discharging mixed flows, and controller for thrust produced by engine. To change level of engine thrust between transonic push operation and supersonic cruise operation, controller adjusts one or more components which vary relative areas available for hot exhaust gas flow and cold bypass airflow at mixer while holding fan inlet non-dimensional mass flow w {square root over ()} T/P substantially constant, where w is mass flow of incoming air at fan inlet, T is stagnation temperature of incoming air at fan inlet and P is stagnation pressure of incoming air at fan inlet.

Airframe integrated scramjet engines are disclosed. Scramjet engines within the scope of this disclosure may be configured to integrate smoothly with an airframe of a hypersonic flight aircraft or vehicle. The scramjet engine may include capture shape of an inlet configured to capture airflow, a combustor configured for combustion of fuel and air, and an exit shape of a nozzle configured for expansion of the combusted fuel and air to provide hypersonic thrust. In some embodiments, the scramjet engine has a fixed geometry and a transitioning cross-sectional shape over its full length. The scramjet engine is configured to be a component of launch vehicle system.

An inlet duct for use with an engine is presented. The invention includes a duct structure, at least one spike disposed along an interior surface of the duct structure, and an inlet throat formed by one or more apexes disposed along an equal number of spikes. The inlet throat corresponds to the minimum cross-sectional area through which airflow passes as otherwise allowed by the maximal obstruction formed by the apex(es) within the duct structure. Each spike is bounded by a longitudinal ridge and a lateral ridge along an upper end and a base. The ridges intersect at the apex. A portion of each spike upstream of the inlet throat functions primarily as a supersonic diffuser and downstream as a subsonic diffuser. Airflow is isentropically compressed and then expanded within the inlet duct so that greater-than-subsonic flow at an input end is reduced to subsonic flow at an output end.