Abstract: A gas distribution system may include a gas mass flow sensor with a resistive element configured to be heated, a thermally conductive shell surrounding the resistive element and heat-transfer control elements. The shell may include a leading surface oriented substantially orthogonal to a direction of gas flow. The heat-transfer control elements may be positioned to focus heat transfer from the resistive element through the leading surface of the shell so that a rate of heat transfer is independent from the variations in flow configuration.

Abstract: A gas distribution system may include a gas mass flow sensor with a resistive element configured to be heated, a thermally conductive shell surrounding the resistive element and heat-transfer control elements. The shell may include a leading surface oriented substantially orthogonal to a direction of gas flow. The heat-transfer control elements may be positioned to focus heat transfer from the resistive element through the leading surface of the shell so that a rate of heat transfer is independent from the variations in flow configuration.

Abstract: Embodiments of a turbomachine, such as a gas turbine engine, are provided. In one embodiment, the turbomachine includes an impeller, a main intake plenum in fluid communication with the inlet of the impeller, and an impeller shroud recirculation system. The impeller shroud recirculation system includes an impeller shroud extending around at least a portion of the impeller and having a shroud port therein. A shroud port cover circumscribes at least a portion of the shroud port and cooperates therewith to at least partially define an impeller recirculation flow path. The impeller recirculation flow path has an outlet positioned to discharge airflow into the main intake plenum at a location radially outboard of the shroud port when pressurized air flows from the impeller, through the shroud port, and into the impeller recirculation flow path during operation of the turbomachine.

Abstract: Embodiments of a turbomachine, such as a gas turbine engine, are provided. In one embodiment, the turbomachine includes an impeller, a main intake plenum in fluid communication with the inlet of the impeller, and an impeller shroud recirculation system. The impeller shroud recirculation system includes an impeller shroud extending around at least a portion of the impeller and having a shroud port therein. A shroud port cover circumscribes at least a portion of the shroud port and cooperates therewith to at least partially define an impeller recirculation flow path. The impeller recirculation flow path has an outlet positioned to discharge airflow into the main intake plenum at a location radially outboard of the shroud port when pressurized air flows from the impeller, through the shroud port, and into the impeller recirculation flow path during operation of the turbomachine.

Abstract: A launch and capture system for capturing a vertical take-off and landing (VTOL) vehicle having a thruster and a duct configured to direct airflow generated by the thruster includes a capture plate and an extension. The capture plate is configured to alter the airflow and generate a force attracting the duct to the capture plate. The extension is coupled to the capture plate, and is configured to at least facilitate holding the VTOL vehicle against the capture plate.

Abstract: An inertial inlet particle separator system for a vehicle engine includes an inertial inlet particle separator and an adjustment mechanism. The separator includes a fluid inlet coupled to a scavenge channel and to a clean channel such that a first amount of fluid passing through the fluid inlet enters the scavenge channel and a second amount of fluid passing through the fluid inlet enters the clean channel. The scavenge channel is defined by a first wall and a splitter, and the clean channel is defined by a second wall and the splitter. The splitter and the second wall are stationary with respect to each other. The adjustment mechanism is coupled to the inertial inlet particle separator and configured to adjust a size of the scavenge channel. Although not necessarily, the adjustment mechanism may also be coupled to the scavenge fan speed.

Abstract: An exhaust muffler is provided for a turbine engine with at least first and second exhaust outlets. The exhaust muffler includes a first arm configured to be coupled to the first exhaust outlet of the turbine engine. The first arm includes an outer surface, and an inner surface that defines a first exhaust cavity. The first arm further includes a plurality of perforations extending between the inner and outer surfaces. The exhaust muffler further includes a second arm coupled to the first arm and configured to be coupled to the second exhaust outlet of the turbine engine. The second arm includes an outer surface, and an inner surface that defines a second exhaust cavity. The second arm also includes a plurality of perforations extending between the inner and outer surfaces.

Abstract: An eductor assembly is provided that includes a primary nozzle, a cooler plenum, and a surge plenum. In one embodiment, and by way of example only, the primary nozzle is configured to accelerate and discharge turbine exhaust gas therefrom and the cooler plenum surrounds the primary nozzle and includes at least a fluid inlet and a fluid outlet. The surge plenum partially surrounds the primary nozzle and the cooler plenum and includes at least a fluid inlet and a fluid outlet. The surge plenum fluid outlet axially aligns and is coterminous with the cooler plenum fluid outlet.

Abstract: An inlet door assembly and method for reducing noise from an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet assembly includes an inlet duct, an actuator, and a door. The inlet duct is configured to extend from the auxiliary power unit to the aircraft housing and has a sidewall that defines a flow passage through which APU noise propagates. The actuator is disposed at least partially within the inlet duct. The door coupled to the actuator. The actuator is also configured to selectively rotate the door between at least a first position, in which at least a portion of the door deflects APU noise in a first direction, and a second position, in which at least a portion of the door deflects the APU noise in a second direction.

Abstract: An inlet door assembly for reducing air pressure loss and enhancing performance of an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet door assembly includes a duct and a diffuser. The duct, which is configured to be movably coupled to an aircraft and to move between open and closed positions, has a flow passage extending therethrough. Air external to the aircraft flows through the duct while it is in the open position, but not while it is in the closed position. The diffuser is coupled to the duct and configured to move therewith. The diffuser has a passage extending therethrough that is in fluid communication with the duct flow passage, and is configured to diffuse the air that flows therethrough.

Abstract: A launch and capture system for capturing a vertical take-off and landing (VTOL) vehicle having a thruster and a duct configured to direct airflow generated by the thruster includes a capture plate and an extension. The capture plate is configured to alter the airflow and generate a force attracting the duct to the capture plate. The extension is coupled to the capture plate, and is configured to at least facilitate holding the VTOL vehicle against the capture plate.

Abstract: An inertial inlet particle separator system for a vehicle engine includes an inertial inlet particle separator and an adjustment mechanism. The separator includes a fluid inlet coupled to a scavenge channel and to a clean channel such that a first amount of fluid passing through the fluid inlet enters the scavenge channel and a second amount of fluid passing through the fluid inlet enters the clean channel. The scavenge channel is defined by a first wall and a splitter, and the clean channel is defined by a second wall and the splitter. The splitter and the second wall are stationary with respect to each other. The adjustment mechanism is coupled to the inertial inlet particle separator and configured to adjust a size of the scavenge channel. Although not necessarily, the adjustment mechanism may also be coupled to the scavenge fan speed.

Abstract: An auxiliary power unit (APU) compartment air inlet system seals, via one or more inlet doors driven by a single actuator, an APU compartment, and isolates the APU inlet and cooling system inlets from each other. The system includes either one or two inlet doors, depending on the number of ram air inlets formed in the APU compartment. In either instance, however, a single actuator is used to move the inlet door(s) between open and closed positions.

Abstract: An inlet door assembly and method for reducing noise from an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet assembly includes an inlet duct, an actuator, and a door. The inlet duct is configured to extend from the auxiliary power unit to the aircraft housing and has a sidewall that defines a flow passage through which APU noise propagates. The actuator is disposed at least partially within the inlet duct. The door coupled to the actuator. The actuator is also configured to selectively rotate the door between at least a first position, in which at least a portion of the door deflects APU noise in a first direction, and a second position, in which at least a portion of the door deflects the APU noise in a second direction.

Abstract: An inlet door assembly and method for reducing noise from an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet assembly includes an inlet duct, an actuator, and a door. The inlet duct is configured to extend from the auxiliary power unit to the aircraft housing and has a sidewall that defines a flow passage through which APU noise propagates. The actuator is disposed at least partially within the inlet duct. The door coupled to the actuator. The actuator is also configured to selectively rotate the door between at least a first position, in which at least a portion of the door deflects APU noise in a first direction, and a second position, in which at least a portion of the door deflects the APU noise in a second direction.

Abstract: Systems and methods are provided for reducing pressure loss of air flowing from a first area in a first direction to a second area in a second direction. The systems include a flow surface, first and second fence walls, an opening, and a flow path. The flow surface defines a portion of the first area. The fence walls extend substantially parallel to each other along the flow surface in the first direction. The opening is formed in the flow surface and is disposed between the first and second fence walls. The flow path defines at least a portion of the second area and is in flow communication with the opening to receive a portion of the airflow and to direct the airflow in the second direction. Methods of using and manufacturing the systems are also provided.

Abstract: An exhaust muffler is provided for a turbine engine with at least first and second exhaust outlets. The exhaust muffler includes a first arm configured to be coupled to the first exhaust outlet of the turbine engine. The first arm includes an outer surface, and an inner surface that defines a first exhaust cavity. The first arm further includes a plurality of perforations extending between the inner and outer surfaces. The exhaust muffler further includes a second arm coupled to the first arm and configured to be coupled to the second exhaust outlet of the turbine engine. The second arm includes an outer surface, and an inner surface that defines a second exhaust cavity. The second arm also includes a plurality of perforations extending between the inner and outer surfaces.

Abstract: A venturi gate valve assembly for extraction of bleed air flow from an auxiliary power unit (APU) and an APU compartment including the venturi gate valve assembly. The venturi gate valve assembly is configured to isolate and restrict bleed air flow from the APU via an extraction conduit. The venturi gate valve assembly includes an upstream valve flange, a throat area, a moveable valve gate, and a downstream valve flange, in fluid communication defining a bleed air flow path. A conical shaped diffuser is defined along the bleed air flow path from the throat area to the downstream flange.

Abstract: An auxiliary power unit (APU) includes a compressor, a turbine, a combustor, and a starter-generator unit all integrated within a single containment housing. The turbine has an output shaft on which the compressor is mounted, and the starter-generator unit is coupled to the turbine output shaft without any intervening gears. The rotating components are all rotationally supported within the containment housing using bearings that do not receive a flow of lubricating fluid.

Abstract: An inlet door assembly and method for reducing noise from an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet assembly includes an inlet duct, an actuator, and a door. The inlet duct is configured to extend from the auxiliary power unit to the aircraft housing and has a sidewall that defines a flow passage through which APU noise propagates. The actuator is disposed at least partially within the inlet duct. The door coupled to the actuator. The actuator is also configured to selectively rotate the door between at least a first position, in which at least a portion of the door deflects APU noise in a first direction, and a second position, in which at least a portion of the door deflects the APU noise in a second direction.