A clearance control device including a segment having a passage to deliver fluid towards a component rotating past the segment. Also a fluid flow device having a first fluid path coupled to the passage and a second fluid path that is decoupled from the passage. A first plasma generator is located in the fluid flow device that directs fluid towards the first fluid path; a second plasma generator is located in the fluid flow device that directs fluid towards the second fluid path; and a control arrangement is configured to alternately energize the first and second plasma generators at an energizing frequency to deliver fluid to the passage at a frequency coincident with the passing frequency of the component.

Systems and methods for monitoring aerostructures are provided. In various embodiments, a method for monitoring an aerostructure may include: receiving a signal from a pressure sensor, the pressure sensor located downstream from the aerostructure; performing a time frequency analysis on the signal to calculate a power level over a range of frequencies; monitoring the power level over the range of frequencies; and determining a susceptibility to a flutter condition based on the monitoring the power level.

An aero damping measurement system is provided. The system includes a shroud defining a tunnel, a hub disposed within the tunnel, and a plurality of blades coupled to the hub. The blades may rotate about the hub. A gas pressure probe may have a tip extending to the tunnel to deliver a pressurized burst into the tunnel. An aeromechanical identification system may include a pressurized gas source, a valve in fluid communication with the pressurized gas source, and the gas pressure probe may be in fluid communication with the valve. The valve may control a flow of a pressurized gas from the pressurized gas source into the gas pressure probe. A pressure sensor may be coupled to the gas pressure probe and configured to measure a pressure within the gas pressure probe.

New exemplary heat exchange configurations that incorporate internal or external surfaces equipped with perturbators, for changing the thermal behavior of the system, or for modulating the surface temperature distribution of the flow surfaces. This is achieved by applying an acoustic wave to the fluid flow in a heat exchange passage, and selecting the frequency of the acoustic exciting wave to be the same as the acoustic resonance frequency of the heat exchange passage itself. As the traveling waves interact with the boundaries confining the heat exchange passages, constructive interference of the incident and reflected waves give rise to a standing wave. Thus, the heat exchange passages act as a resonator, and by superimposing this standing wave on the separating and reattaching fluid flow, significant heat transfer improvement can be achieved. This is accomplished without the need to significantly increase the pressure required to achieve the desired through flow.

An aero damping measurement system is provided. The system includes a shroud defining a tunnel, a hub disposed within the tunnel, and a plurality of blades coupled to the hub. The blades may rotate about the hub. A gas pressure probe may have a tip extending to the tunnel to deliver a pressurized burst into the tunnel. An aeromechanical identification system may include a pressurized gas source, a valve in fluid communication with the pressurized gas source, and the gas pressure probe may be in fluid communication with the valve. The valve may control a flow of a pressurized gas from the pressurized gas source into the gas pressure probe. A pressure sensor may be coupled to the gas pressure probe and configured to measure a pressure within the gas pressure probe.

In one embodiment, a power generation system includes a pulse detonation engine including a combustion chamber, a linear power generator including a working chamber, and a nozzle positioned between the combustion chamber and the working chamber that expands exhaust gas expelled from the combustion chamber, wherein the nozzle increases thermodynamic efficiency of the system.

Methods and apparatus for reducing flow distortion at engine fans of nacelles are disclosed. An example apparatus for reducing flow distortion at an engine fan of a nacelle includes a plurality of nozzles radially spaced about an inner wall of the nacelle. In some examples, respective ones of the nozzles are positioned to eject corresponding respective jets of fluid adjacent the inner wall in a downstream direction toward the engine fan. The example apparatus further includes a controller to selectively activate the respective ones of the nozzles according to a time-based sequence. In some examples, the time-based sequence corresponds to a directional sequence that moves in an arcuate direction along a circumference of the inner wall.

A blade vibration damping system impacts a pressurized damping fluid on a surface of at least one of a plurality of blades of a turbine in opposition to a vibratory movement thereof to cause damping of vibration of the blade(s) during operation of the turbine. The system includes a fluid injection nozzle in a stationary component adjacent the plurality of blades. A valve selectively admits the pressurized damping fluid to the fluid injection nozzle from a source of pressurized damping fluid, and a control system controls the valve to operate the fluid injection nozzle in response to an operational parameter exceeding a threshold during operation of the turbine. A related turbine casing and method are also provided.

A power source is configured to apply a first alternating electric excitation signal to an oscillation blade device at a first excitation frequency causing a blade of the oscillation blade device to oscillate at a first oscillation frequency. A current detector is configured to measure amplitude values of the current supplied by the power source to the oscillation blade device. A processor is configured to assess a plurality of successive peak values of the measured amplitudes, determine a second oscillation frequency for the blade if variation in the successive peak values is detected and send a command to the power source to apply a second alternating electric excitation signal to the oscillation blade device at a second excitation frequency which matches the determined second oscillation frequency.

New exemplary heat exchange configurations that incorporate internal or external surfaces equipped with perturbators, for changing the thermal behavior of the system, or for modulating the surface temperature distribution of the flow surfaces. This is achieved by applying an acoustic wave to the fluid flow in a heat exchange passage, and selecting the frequency of the acoustic exciting wave to be the same as the acoustic resonance frequency of the heat exchange passage itself. As the traveling waves interact with the boundaries confining the heat exchange passages, constructive interference of the incident and reflected waves give rise to a standing wave. Thus, the heat exchange passages act as a resonator, and by superimposing this standing wave on the separating and reattaching fluid flow, significant heat transfer improvement can be achieved. This is accomplished without the need to significantly increase the pressure required to achieve the desired through flow.