Abstract: A refrigeration circuit includes a primary loop, a secondary loop connected to the primary loop, a first expansion valve connected to the secondary loop, and a second expansion valve. The second expansion valve is connected to the secondary loop and is in parallel with the first expansion valve to control thermal communication between the refrigeration circuit and a first heat load independent of thermal communication between the refrigeration circuit and a second heat load. Environmental control systems and methods of controlling refrigerant flow in refrigeration circuits are also described.

Abstract: An environmental control system includes a refrigerant circuit with a pump segment and an evaporator segment, an evaporator arranged along the evaporator segment and in fluid communication with of the refrigerant circuit, and a coolant circuit. The coolant circuit extends through the evaporator and is thermally coupled to refrigerant circuit by the evaporator, the coolant circuit including a first segment and a second segment arranged in parallel with one another to transfer heat from a first zone to a first portion of liquid coolant traversing the coolant circuit and transfer additional heat from a second zone to a second portion of coolant traversing the coolant circuit. Aircraft and environmental control systems are also described.

Abstract: A header duct and method of forming a header duct includes an inlet portion having a planar inlet, an outlet portion have a plurality of planar outlets, and a transition portion extending continuously from the inlet portion to the outlet portion. The transition portion has a bend and internal topography defining a non-monotonic cross-sectional area distribution between the inlet and outlet portions. The transition portion can further include a bulbous region extending in a lateral direction of the duct and a protrusion located along an inside radius of the bend.

Abstract: Provided are embodiments for a system for offloading non-thrust loads. The system includes one or more thrust loads, and one or more non-thrust loads, and a controller that is operably coupled to the one or more thrust loads and the one or more non-thrust loads. The controller is configured to control the thrust loads and non-thrust loads, receive input from one or more sources, and identify a phase of flight based at least in part on the received input. The controller is also configured to offload one or more non-thrust loads during the phase of flight, and restore the one or more non-thrust loads. Also provided are embodiments for method for offloading non-thrust loads.

Abstract: Disclosed is an aircraft including ductwork. The ductwork includes a cabin recirculation vent disposed to draw air from an aircraft cabin. The ductwork includes a riser defining a return conduit disposed to convey air from the cabin recirculation vent. The ductwork includes a thermoelectric heat pump having a first side and a second side, the first side in thermal contact with the return conduit that transfers heat to the second side upon application of an electrical input.

Abstract: A fan motor housing including a circumferential motor housing having a radially outer surface and a radially inner surface and defining a primary axis including a first plurality of concentric flow channels disposed between the radially outer surface the radially inner surface, wherein the concentric flow channels extend in an axial direction parallel to the primary axis, a second plurality of concentric flow channels disposed between the radially outer surface and the radially inner surface, extending in an axial direction parallel to the primary axis, wherein the first and second pluralities of concentric flow channel are thermodynamically connected, a first plurality of radial conduits connecting the second plurality of flow channels to the radially inner surface of the motor housing, and a second plurality of radial conduits connecting the radially inner surface of the motor housing to the second plurality of flow channels.

Abstract: A header duct and method of forming a header duct includes an inlet portion having a planar inlet, an outlet portion have a plurality of planar outlets, and a transition portion extending continuously from the inlet portion to the outlet portion. The transition portion has a bend and internal topography defining a non-monotonic cross-sectional area distribution between the inlet and outlet portions. The transition portion can further include a bulbous region extending in a lateral direction of the duct and a protrusion located along an inside radius of the bend.

Abstract: A heat exchanger system includes an additively manufactured inlet header upstream of, and in fluid communication with, the heat exchanger core and an additively manufactured exit header downstream of, and in fluid communication with, the heat exchanger core. A method of manufacturing a header for a ducted heat exchanger system for a gas turbine engine includes additively manufacturing a header with respect to a desired airflow therethrough.

Abstract: A system and method for enhancing a diffusion limited CVI/CVD process is provided. The system may densify a porous structure by flowing a reactant gas around the porous structure. A mass flow controller may be configured to pulse the flow rate of the reactant gas around the porous structure. The mass flow controller may pulse the flow rate from a nominal flow rate to a first flow rate. The mass flow controller may pulse the first flow rate back to the nominal flow rate or to a second flow rate. The mass flow controller may pulse the flow rate between the nominal flow rate, the first flow rate, and the second flow rate, as desired.

Abstract: An environmental control system that includes a first environmental control system pack, a first recirculation fan assembly, and a cabin air sensor unit. The first environmental control system pack is arranged to provide conditioned air to an aircraft cabin. The first recirculation fan assembly is arranged to recirculate a first cabin air fluid flow back to the aircraft cabin. The cabin air sensor unit is arranged to provide a first air quality signal indicative of an air quality of the first cabin air fluid flow to a controller.

Abstract: A system and method for enhancing a diffusion limited CVI/CVD process is provided. The system may densify a porous structure by flowing a reactant gas around the porous structure. A mass flow controller may be configured to pulse the flow rate of the reactant gas around the porous structure. The mass flow controller may pulse the flow rate from a nominal flow rate to a first flow rate. The mass flow controller may pulse the first flow rate back to the nominal flow rate or to a second flow rate. The mass flow controller may pulse the flow rate between the nominal flow rate, the first flow rate, and the second flow rate, as desired.

Abstract: An environmental control system that includes a first environmental control system pack, a first recirculation fan assembly, and a cabin air sensor unit. The first environmental control system pack is arranged to provide conditioned air to an aircraft cabin. The first recirculation fan assembly is arranged to recirculate a first cabin air fluid flow back to the aircraft cabin. The cabin air sensor unit is arranged to provide a first air quality signal indicative of an air quality of the first cabin air fluid flow to a controller.

Abstract: A heat exchanger includes a plate with an external surface, a channel, and a nozzle. The external surface bounds an interior of the plate. The channel is disposed in the heat exchanger and passes through a portion of the interior. The nozzle is integrally disposed in the heat exchanger, extends through a portion of the external surface, and is fluidly connected to the channel. The nozzle is configured to transport a liquid from the channel, through the external surface, and to distribute the liquid onto a portion of the heat exchanger.

Abstract: A heat exchanger includes a body shaped to integrate with one or more system structural elements and a plurality of first flow channels defined in the body. The heat exchanger also includes a plurality of second flow channels defined in the body. The second flow channels are fluidly isolated from the first flow channels. The first flow channels and the second flow channels have a changing flow direction characteristic along a direction of flow within the first flow channels and the second flow channels.

Abstract: A method of cooling a component with a heat exchange device includes pulling air into a central airway in a heat exchange device using a blower; directing the air from the blower through a diffuser and across a heat sink base, wherein a first component positioned underneath the heat sink base is cooled when the air passes over the heat sink base; and directing the air out from the diffuser and across a second component to cool the second component.

Abstract: Embodiments are directed to selecting, by a computing device comprising a processor, the size of at least one prime mover associated with an aircraft to satisfy a baseline power requirement for operation of the aircraft during a steady state load condition, selecting at least one power source configuration to supplement power provided by the at least one prime mover during a transient load condition associated with the operation of the aircraft, and selecting, by the computing device, a parameter of the at least one power source configuration to provide a total power in an amount that is greater than a threshold during the transient condition.

Abstract: A system and method of using the system includes an open-loop path and a closed-loop path. The open-loop path is configured to extract bleed air from a compressor section of a gas turbine engine through a bleed air port and discharge bleed air to an ambient environment. The closed-loop path is configured to circulate a working fluid through a heat exchanger, a turbine, and a condenser with a pump. The heat exchanger is fluidly coupled to the bleed air port and configured to extract heat from the bleed air to boil the working fluid for driving the turbine and a component rotationally coupled to the turbine.

Abstract: A process for densifying an annular porous structure comprising flowing a reactant gas into an inner diameter (ID) volume and through an ID surface of the annular porous structure, flowing the reactant gas through an outer diameter (OD) surface of the annular porous structure and into an OD volume, flowing the reactant gas from the OD volume through the OD surface of the annular porous structure, and flowing the reactant gas through an ID surface of the annular porous structure and into the ID volume.

Abstract: A counterflow heat exchanger configured to exchange heat between a first fluid flow at a first pressure and a second fluid flow at a second pressure includes a first fluid inlet, a first fluid outlet fluidly coupled to the first fluid inlet via a core section, a second fluid inlet, and a second fluid outlet fluidly coupled to the second fluid inlet via the core section. The core section includes a plurality of first fluid passages configured to convey the first fluid flow from the first fluid inlet toward the first fluid outlet, and a plurality of second fluid passages configured to convey the second fluid flow from the second fluid inlet toward the second fluid outlet such that the first fluid flow exchanges thermal energy with the second fluid flow at the core section. Each first fluid passage of the plurality of first fluid passages has a circular cross-section.

Abstract: A counterflow heat exchanger configured to exchange thermal energy between a first fluid flow at a first pressure and a second fluid flow at a second pressure less than the first pressure includes a first fluid inlet, a first fluid outlet fluidly coupled to the first fluid inlet via a core section, a second fluid inlet, and a second fluid outlet fluidly coupled to the second fluid inlet via the core section. A heating arrangement is configured to heat the second fluid inlet to prevent ice ingestion via the second fluid inlet.