A fluid cooling system for use in a gas turbine engine including a fan casing circumscribing a core gas turbine engine includes a heat source configured to transfer heat to a heat transfer fluid and a primary heat exchanger coupled in flow communication with the heat source. The primary heat exchanger is configured to channel the heat transfer fluid therethrough and is coupled to the fan casing. The fluid cooling system also includes a secondary heat exchanger coupled in flow communication with the primary heat exchanger. The secondary heat exchanger is configured to channel the heat transfer fluid therethrough and is coupled to the core gas turbine engine. The fluid cooling system also includes a bypass mechanism coupled in flow communication with the secondary heat exchanger. The bypass mechanism is selectively moveable based on a temperature of a fluid medium to control a cooling airflow through the secondary heat exchanger.

Electrical systems for connecting rotary electric machines to dc networks operating at different voltages V and W where V>W are provided, along with gas turbine engine arrangements incorporating such systems.

Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

A dual volute turbocharger for use with an internal combustion engine includes a valve for controlling exhaust gas flow to a turbine housing interior of the dual volute turbocharger. The dual volute turbocharger also includes a first volute and a second volute each adapted for fluid communication with the internal combustion engine. The dual volute turbocharger further includes a wall separating the first and second volutes and a valve seat. The valve seat and the wall collectively define a valve cavity. The valve is movable between a closed position and an open position. The valve and the wall of the turbine housing collectively define a first cross-sectional flow area. The valve and the valve seat collectively define a second cross-sectional flow area. A method of controlling the valve of the dual volute turbocharger is also disclosed.

Apparatus and associated methods relate to simultaneously pumping and measuring density of an aircraft fuel. The aircraft fuel is pumped by a centrifugal pump having an impeller. A rotational frequency of the impeller is determined while the centrifugal pump is pumping the aircraft fuel. Flow rate of the aircraft fuel through the centrifugal pump is sensed. Pressure of the aircraft fuel is measured at two different points within or across the centrifugal pump or a differential pressure is measured between the two different points while the centrifugal pump is pumping the aircraft fuel. Density of the aircraft fuel is determined based on a head-curve relation characterizing the centrifugal pump. The head-curve relation relates the fuel density to the rotational frequency, the flow rate, and pressures at the two different points or the differential pressure between the two different points.

A fuel oxygen reduction unit for an engine is provided. The fuel oxygen reduction unit includes an inlet fuel line; a stripping gas source; a contactor selectively in fluid communication with the stripping gas source, the inlet fuel line, or both to form a fuel/gas mixture; and a separator that receives the fuel/gas mixture, the separator configured to separate the fuel/gas mixture into an outlet stripping gas flow and an outlet fuel flow; wherein a flow of stripping gas passes through the fuel oxygen reduction unit a single time.

The present invention belongs to the technical field of modeling and simulation of an aeroengine, and provides a method of modeling, simulation and fault injection for a combined high pressure gear pump for an aeroengine, which comprises: extracting the flow regions of a centrifugal pump and a gear pump in the aeroengine and merging into a combined flow region; dividing the combined flow region into different units according to a working principle; meshing each unit by a finite element analysis method, and setting boundary conditions and media parameters; simulating in Pumplinx to obtain the operation performance of the pumps, and adjusting the lateral clearance of the gear to debug the simulation model till a simulation error is within 5%; and then setting faults based on the debugged model to obtain the change of the operation performance of the pumps under the faults.

Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

A gas turbine engine includes a compressor section having a first portion and an aft portion. A compressor case clearance (CCC) control system is configured to adjust an amount of bleed air delivered to the front portion and the aft portion based on an in-flight phase of an aircraft. In response to invoking a first mode, the CCC control system delivers air to both the front portion and the aft portion. In response to invoking a second mode, the CCC control system reduces the amount of air delivered to the aft portion prior to transitioning from the cruise phase to the descent phase. Accordingly, clearance areas within the compressor section can be selectively increased during specific portions of the flight to avoid contact between blade tips and the engine case.

A gas turbine engine for an aircraft, comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine, the first electric machine having a first maximum output power; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine, the second electric machine having a second maximum output power; and an engine controller configured to identify a condition to the effect that the LP turbine is operating in an unchoked regime, and, in response to an electrical power demand being between zero and the first maximum output power, only extracting electrical power from the first electric machine to meet the electrical power demand.