A steam turbine 1 includes a turbine body 11 which includes a rotor 5 which is configured to rotate around an axis Ac, and a casing 6 which covers the rotor 5 to form a flow path through which steam flows in an axis Ac direction, together with the rotor 5, a thermal insulation member 12 which is provided to be in contact with an outer surface of the casing 6 in a high-pressure side region 61 out of the high-pressure side region 61 and a low-pressure side region 62 of the steam in the axis Ac direction of the casing 6, and a soundproof cover 13 which covers the low-pressure side region 62 out of the high-pressure side region 61 and the low-pressure side region 62 via a space between the outer surface of the casing 6 and the soundproof cover 13.

A gas turbine engine assembly includes a static component and a rotatable component configured to rotate about a central axis of the gas turbine engine assembly relative to the static component. The gas turbine engine assembly further includes a vibration-dampening system configured to dampen vibration of the gas turbine engine assembly.

A bearing assembly for a rotatable shaft, the bearing assembly comprising: a bearing housing; a bearing located within the bearing housing having an axis of rotation and arranged to receive a rotatable shaft; a first spring bar that couples the bearing to the bearing housing, the first spring bar being configured to tune vibrations of the rotatable shaft; and a first piezoelectric actuator disposed between the bearing housing and the first spring bar, the first piezoelectric actuator being configured to extend in a first direction, wherein extension of the piezoelectric actuator in the first direction displaces the first spring bar relative to the bearing housing.

A turbomachine vane includes an electroacoustic source including two membranes fixed on a support arranged such that the membranes and the support delimit a first cavity. The membranes are arranged on two opposite sides of the first cavity between the two aerodynamic surfaces of the vane. A first of the aerodynamic surfaces includes a first region arranged facing a first of the membranes for the passage of acoustic waves. The membranes and membrane vibration device are configured such that the membranes vibrate in phase opposition and along a same emission direction by applying forces to the support such that the resultant force is approximately zero. The mechanical energy lost in the form of vane deformations due to membrane vibrations can thus be minimized.

Disclosed is a flutter damper, including an acoustic liner configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber, and a piezoelectric element disposed within a first surface of the chamber, 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 wherein the piezoelectric element is operatively connected to an electronic engine control.

A blisk assembly for vibration dampening includes a disk portion extending circumferentially about a central axis of the blisk, a plurality of blades integrally coupled to the disk, and a piezoelectric damping ring that includes a damping ring and a plurality of piezoelectric elements coupled to the damping ring. The disk portion includes a groove configured to receive the piezoelectric damping ring. As a result of centrifugal forces applied to the piezoelectric damping ring during rotation of the blisk assembly, mechanical energy may be generated at one or more of the plurality of piezoelectric elements, which is converted to electrical energy and transmitted to another one or more of the plurality of piezoelectric elements. Accordingly, the one or more of the piezoelectric elements having received the electricity can convert the electricity to mechanical energy to provide vibration damping.

A system for airfoil vibration control is generally provided. The system includes an airfoil including a ferromagnetic material, and a static structure including an electromagnet adjacent to the ferromagnetic material of the airfoil. A method for controlling vibration at an airfoil of a turbo machine is further provided. The method includes placing a ferromagnetic material at the airfoil, placing an electromagnet at a static structure adjacent to the ferromagnetic material at the airfoil, and applying an electromagnetic force to the ferromagnetic material at the airfoil via the electromagnet at the static structure.

A gas turbine engine includes an airfoil and a deicing system. The airfoil radially extends from a hub towards a case disposed about a central longitudinal axis of the gas turbine engine. The deicing system includes an acoustic driver assembly arranged to apply acoustic energy to the airfoil to excite a predetermined vibratory mode of the airfoil.

Health monitoring systems and associated methods for gas turbine engines are provided. A health monitoring method includes using a microphone to acquire operation data indicative of acoustic energy generated in a core gas path of the gas turbine engine. The operation data is compared to reference data indicative of an acoustic signature of fluid noise associated with a non-normal condition in the core gas path of the gas turbine engine. Based on the comparing of the operation data to the reference data, the non-normal condition is determined to exist within the core gas path of the gas turbine engine. A signal indicative of the existence of the non-normal condition within the core gas path of the gas turbine engine is output.

A noise reduction device includes: a first waveform acquisition unit configured to acquire, based on a reference signal that is obtained by detecting vibration at a first position of an exhaust duct of a gas turbine, a first waveform representing vibration of the exhaust duct; an unbalanced motor configured to apply, at a second position of the exhaust duct, vibration at a target frequency designated for the exhaust duct; a second waveform acquisition unit configured to acquire, based on a measurement signal obtained by measuring a rotation pulse of the unbalanced motor, a second waveform representing rotation of the unbalanced motor; a setting unit configured to set the target frequency based on the first waveform; and a correction unit configured to correct the target frequency, to achieve a predetermined phase difference between the first waveform and the second waveform.