Abstract: Disclosed is flutter damper including a first cavity having a radially inner side in fluid communication with a flow path, and a second cavity having a radially inner side in fluid communication with a radially outer side of the first cavity, and the flutter damper having an impedance characteristic at one or more target frequencies defined as ftarget=fS,ND+?·ND wherein fS,ND is a resonance frequency corresponding to a structural mode of a rotating component, ND is a nodal diameter count of the structural mode, and ? is a rotational speed of the rotating component, and wherein the flutter damper has the following impedance characteristic at the one or more targeted frequencies R?2?c ?3?c?X??0.6?c wherein R is the real part of the impedance characteristic, X is the imaginary part of the impedance characteristic, ? is air density, and c is speed of sound.

Abstract: A bearing assembly is provided. The bearing assembly includes an inner race configured to couple to a shaft, an outer race disposed around the inner race, and a housing disposed around the outer race. The housing and the outer race define an annulus and a buffer region, and the buffer region defines an axial boundary of the annulus.

Abstract: A fluid damping structure is provided that includes an inner and outer annular elements, first and second ring seals, first and second outer annular seals. The inner annular element has an outer radial surface and a plurality of annular grooves disposed in the outer radial surface. The outer annular element has an inner radial surface. A damping chamber is defined by the inner and outer annular elements, and the first and second inner ring seal. A first lateral chamber is disposed on a first axial side of the damping chamber. A second lateral chamber is disposed on a second axial side of the damping chamber. A plurality of fluid passages are disposed in at least one of the inner annular element or the inner ring seals. The fluid damping structure is configurable in an open configuration and a closed configuration.

Abstract: A fluid damping structure is provided that includes an inner annular element, an outer annular element, a first outer seal, a second outer seal, an inner seal, a damping chamber, a supply plenum, a fill port, and a plurality of fluid passages. The plurality of fluid passages is disposed in at least one of the inner annular element or the inner seal. The fluid damping structure is configured such that one or more of the fluid passages is disposed in an open configuration when a local damping fluid pressure within the damping chamber is less than a local damping fluid pressure in an adjacent region of the supply plenum, and the one or more of the fluid passages is disposed in a closed configuration when the local damping fluid pressure within the damping chamber is greater than the local damping fluid pressure in the adjacent region of the supply plenum.

Abstract: A gas turbine engine may include a liftoff carbon seal assembly. Liftoff carbon seal assembly may include a static seal support structure, a magnetic carrier spring assembly coupled to the static seal support structure, a nonferrous metal slab magnetically associated with the magnetic carrier spring assembly and coupled to the static seal support structure. In various embodiments, a combination of the magnetic carrier spring assembly and the nonferrous metal slab create a counter-force using an eddy current to oppose a motion of the magnetic carrier spring assembly.

Abstract: A fluid damping structure is provided that includes a damper ring. The damper ring includes an annular body a plurality of fluid check valves, and at least one fluid stop. The annular body extends circumferentially around an axial centerline, and is defined by a first end surface, a second end surface, an outer radial surface, and an inner radial surface. The outer radial surface and the inner radial surface extend axially from the first end surface toward the second end surface. The body includes one or more check valve passages. Each check valve passage extends axially from an open end disposed at the first end surface inwardly toward the second end surface, and is disposed between the inner radial surface and the outer radial surface. An inlet aperture extends between each check valve passage and the outer radial surface, and an outlet aperture extends between each check valve passage and the inner radial surface. Each fluid check valve is disposed in a check valve passage.

Abstract: A squeeze film damper includes a static member and a whirling member positioned adjacent to the static member. A gap is formed between the static member and the whirling member. A pressurized oil reservoir is formed in the gap between the static member and the whirling member. A first low pressure oil reservoir is formed in a first cavity in the whirling member, wherein the first low pressure oil reservoir is positioned on a first end of the pressurized oil reservoir. A second low pressure oil reservoir is formed in a second cavity in the whirling member, wherein the second low pressure oil reservoir is positioned on a second end of the pressurized oil reservoir. A first primary seal is positioned between the first end of the pressurized oil reservoir and the first low pressure oil reservoir, and a second primary seal is positioned between the second end of the pressurized oil reservoir and the second low pressure oil reservoir.

Abstract: A squeeze film damper includes a static member and a whirling member positioned adjacent to the static member. A gap is formed between the static member and the whirling member. A pressurized oil reservoir is formed in the gap between the static member and the whirling member. A first low pressure oil reservoir is formed in a first cavity in the whirling member, wherein the first low pressure oil reservoir is positioned on a first end of the pressurized oil reservoir. A second low pressure oil reservoir is formed in a second cavity in the whirling member, wherein the second low pressure oil reservoir is positioned on a second end of the pressurized oil reservoir. A first primary seal is positioned between the first end of the pressurized oil reservoir and the first low pressure oil reservoir, and a second primary seal is positioned between the second end of the pressurized oil reservoir and the second low pressure oil reservoir.

Abstract: A film damper for a gas turbine engine includes an annular inner member and an annular outer member located radially outboard of the annular inner member, the annular outer member and the annular inner member defining a damper annulus therebetween. A fluid supply passage delivers a flow of fluid into the damper annulus from the annular outer member, and a backflow prevention device is located at the fluid supply passage to prevent backflow of the flow of fluid from the damper annulus into the fluid supply passage.

Abstract: Disclosed is a flutter damper, including an acoustic liner having a perforated radial inner face sheet and a radial outer back sheet, the acoustic liner being configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber secured to the radial outer back sheet, the chamber being in fluid communication with the acoustic liner, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and at least one stiffening structure connected to a top surface of the chamber that tunes the top surface out of the frequency range associated with one or more fan flutter modes.

Abstract: Disclosed is flutter damper including a first cavity having a radially inner side in fluid communication with a flow path, and a second cavity having a radially inner side in fluid communication with a radially outer side of the first cavity, and the flutter damper having an impedance characteristic at one or more target frequencies defined as ftarget=fS,ND+?·ND wherein fS,ND is a resonance frequency corresponding to a structural mode of a rotating component, ND is a nodal diameter count of the structural mode, and ? is a rotational speed of the rotating component, and wherein the flutter damper has the following impedance characteristic at the one or more targeted frequencies R?2?c ?3?c?X??0.6?c wherein R is the real part of the impedance characteristic, X is the imaginary part of the impedance characteristic, ? is air density, and c is speed of sound.

Abstract: A system and method for blade health monitoring is provided. The system and method may improve health diagnostic capabilities for engine blades, thus reducing the risk of blade failure during engine operation, increasing the useful life of each engine blade, and allowing for more accurate maintenance and/or inspection schedules of engine blades. The system may include a health monitoring processor, an excitation actuator, and a health monitoring sensor. The excitation actuator may pulse a force against an engine blade to cause non-integral vibratory excitations in engine blades. The health monitoring sensor may measure the vibratory excitations. The health monitoring processor may analyze the vibratory excitations to determine the health of the engine blade.

Abstract: A method for determining one or more fluid flow parameters for a fluid flowing within a pipe is provided. The fluid is a mixture of solid particles and gas. The method includes the steps of: a) providing a meter operable to determine the velocity of the fluid flow through the pipe, which meter is substantially insensitive to the particulate/gas mass ratio of the fluid flow; b) determining the velocity of the fluid flow within the pipe using the meter; and c) determining a particulate/gas mass ratio using a density value for the gas within the flow and the determined fluid flow velocity.

Abstract: A bearing assembly is provided. The bearing assembly may include an inner race configured to couple to a shaft, an outer race disposed around the inner race, a bearing support structure coupled to the outer race, and a housing disposed around the bearing support structure. The housing and the bearing support structure may define a squeeze-film damper annulus configured to receive an aerated damping fluid. The aerated damping fluid may be provided from a fluid pump and an air supply port.

Abstract: An aeromechanical identification system for turbomachine includes at least one actuator mounted on a stationary structure to excite rotatable airfoils. At least one sensor is mounted proximate the airfoils for measuring a response of the airfoils responsive to excitation from the at least one actuator. A controller is configured to determine a damping characteristic of an aeromechanical mode of the rotating airfoils based on the excitation and the response. A gas turbine engine and a method of determining a flutter boundary for an airfoil of a turbomachine are also disclosed.

Abstract: A method of health monitoring of a gas turbine engine includes mounting a detection system configured to detect an aeromechanical damping characteristic of a row of airfoils of a gas turbine. An actual aeromechanical damping characteristic of the row of airfoils is measured with the detection system. An output signal is generated indicative of the actual aeromechanical damping characteristic of the row of airfoils. A current flutter characteristic is determined based on the output signal indicative of the actual aeromechanical damping characteristic of the row of airfoils. An airfoil health monitoring system for gas turbine engine and a gas turbine engine are also disclosed.

Abstract: A bearing assembly is provided. The bearing assembly includes an inner race configured to couple to a shaft, an outer race disposed around the inner race, and a housing disposed around the outer race. The housing and the outer race define an annulus and a buffer region, and the buffer region defines an axial boundary of the annulus.

Abstract: A film damper for a gas turbine engine includes an annular inner member and an annular outer member located radially outboard of the annular inner member, the annular outer member and the annular inner member defining a damper annulus therebetween. A fluid supply passage delivers a flow of fluid into the damper annulus from the annular outer member, and a backflow prevention device is located at the fluid supply passage to prevent backflow of the flow of fluid from the damper annulus into the fluid supply passage.

Abstract: A gas turbine engine comprises a fan rotor having fan blades received within an outer nacelle. The fan blades are provided with at least a first type having a first natural frequency, and a second type having a second natural frequency. The fan rotor has a first mount structure intended for the first type and a distinct second mount structure intended for the second type. The first type of fan blade fits into the first mount structure intended for the first type, but there is a first obstruction preventing the first type of fan blade from being placed into the second mount structure intended for the second type. The second type of fan blade fits into the second mount structure intended for the second type, but there is a second obstruction preventing the second type of fan blade from being placed into the first mount structure intended for the first type.

Abstract: A method and system for in situ calibrating a flow metering system to monitor fluid flow in a pipe from a well is provided. The method includes the steps of: a) measuring a first characteristic of the fluid flow exiting the well using a DP flow meter during a dry gas period, and producing an first output data representative of the first characteristic; b) measuring a second characteristic of the fluid flow exiting the well using a SONAR flow meter time during the dry gas period, and producing a second output data representative of the second characteristic; c) determining a dry gas offset between the DP flow meter and the SONAR flow meter based on the first output data and the second output data; and d) calibrating the flow metering system using the dry gas offset.