A machine includes a section that defines a target vibrational mode to dampen and a nanocellular foam damper that includes interconnected ligaments in a cellular structure. The interconnected ligaments have an average ligament size defined with respect to a vibrational loss modulus of the nanocellular foam damper and the target vibrational mode. Also disclosed is a method of damping vibration.

The invention relates to a fan module having variable-pitch blades for a turbine engine, including a rotor (2) having blades (3), a stationary casing (7), and a system for adjusting and controlling the pitch of the blades (3), the rotor (2) including a central shaft (6) and a ring (9) for supporting the blades surrounding the shaft, a front end of the ring being connected to a front end of the shaft so as to define an annular space between the ring and the shaft which is open towards the rear, said annular space of the rotor (2) housing said system, and the shaft (6) being guided by a first bearing (8) mounted in the stationary casing (7), to the rear of the ring (9), characterised in that the ring (9) is guided by at least one complementary bearing (31) located upstream of the first bearing (8).

A gas turbine engine includes a compressor rotor shaft assembly, an accessory gearbox, and a bowed-rotor mitigation drive device drivingly coupled with the accessory gearbox. The bowed-rotor mitigation drive device is driven during an engine startup phase so as to induce a mechanical load (mechanical energy) to the bowed-rotor mitigation drive device. The mechanical load (mechanical energy) is retained within the bowed-rotor mitigation drive device during operation of the gas turbine engine. The mechanical load (mechanical energy) retained within the bowed-rotor mitigation drive device is periodically released by the bowed-rotor mitigation drive device in a plurality of periods so as to provide, in each period, a driving force to the accessory gearbox, which provides the driving force to the compressor rotor shaft assembly to periodically rotate the compressor rotor shaft assembly.

A method for producing an integrally bladed rotor includes providing imaginary front and rear lattice points on the ridges of the front and rear edges; providing a first imaginary line on positive-pressure and negative-pressure surfaces to connect a first imaginary front lattice point and a first imaginary rear lattice point; providing a second imaginary line on the positive-pressure and negative-pressure surfaces to connect a second imaginary front lattice point next to the first imaginary front lattice point and a second imaginary rear lattice point next to the first imaginary rear lattice point; providing a spiral path on the positive-pressure and negative-pressure surfaces by connecting the first and second imaginary lines with a spiral curve; and cutting the positive-pressure and negative-pressure surfaces by moving a cutting point corresponding to a cutting edge of a turning tool along the spiral path. point around the blade.

In a vacuum pump, an outer diameter of a spiral plate disposed on a downstream side is set smaller than an outer diameter of a spiral plate disposed on an upstream side. Specifically, a stepped portion is provided by setting a blade length of the spiral plate disposed on the downstream side shorter than a blade length of the spiral plate disposed on the upstream side. In addition, in a spacer provided in the stepped portion, a relief formation portion is provided to allow a contact surface in contact with an upstream spacer (i.e., spacer opposed to the spiral plate having the unreduced outer diameter) and a contact surface in contact with a downstream spacer (i.e., spacer opposed to the spiral plate having the reduced outer diameter) in the stepped portion to have an equal inner diameter.

This invention relates to a multi-stage rotor (10). More specifically, the invention relates to a multistage rotor (10) for the compressor stage of a machine that, through a concentric configuration of its innermost (12), outermost (24) and intermediary (16) blade sets co-operative with a reverse flow convoluting ducting arrangement, provides an axially compact, lighter and more easily maintainable compressor rotor for such machine. The multi-stage rotor (10) includes innermost (30), outermost (34) and intermediary (32) duct ports comprising a radial duct spans, as measured between respective diametrically inner and outer duct walls of the duct port, being greater than respective innermost (48), outermost (54) and intermediary (50, 52) radial blade spans of the respective blade sets rotatable at least partially within such duct port. In this manner, a gap is defined between: (i) the at least one diametrical ends of the radial rotating blades ending radially short of the respective radial duct span to form free ends of the blades; and (ii) a stationary part of the respective duct the free ends of the blades sweep neared to; for generating a friction wash between such free ends of the blades and the stationary part of the respective duct.

A vibration absorber damper and method of dissipating vibration energy in a rotatable structure which is nominally cyclic symmetric. The nominally cyclic symmetric structure includes a hub portion having a rotational axis and a plurality of radial members radially extending from the hub portion. The hub portions having a groove extending circumferentially about the rotational axis. The vibrational absorber having a ring member having a plurality of repetitive cellular structures each defining a hollow interior section and a plurality of deformable members each extending from the ring member and disposed in a corresponding one of the repetitive cellular structures. Each of the deformable members is configured to interact with the cyclic symmetric structure to damp vibration thereof.

A turbomachine includes a housing and a rotating group that is supported for rotation about an axis within the housing. The rotating group includes a rotor shaft, a wheel, and a fastener that clamps the wheel to the rotor shaft. The fastener is unitary and includes a head and a shank. The shank includes a piloting feature on an arcuate surface that faces radially outward with respect to the axis. The shank is received in the wheel and is attached to the rotor shaft with the piloting feature being piloted to an arcuate inner radial surface of the wheel. The head abuts an axial surface of the wheel for axially clamping the wheel to the rotor shaft.

Methods and systems for validating a propeller control unit associated with a propeller having blades are provided. Actuation of a control valve of the propeller control unit is commanded to alter a pitch angle of the blades. One of an actual pitch angle of the blades and an actual rotational speed of the propeller is determined after a predetermined time delay has elapsed. The one of the actual pitch angle of the blades and the actual rotational speed of the propeller is compared to a corresponding one of a pitch angle threshold and a rotational speed threshold, the pitch angle threshold and the rotational speed threshold based on a commanded pitch angle. A warning signal is issued in response to determining one of the actual pitch angle failing to meet the pitch angle threshold and the actual rotational speed failing to meet the rotational speed threshold.

One embodiment is a rotor system including a rotor hub comprising a plurality of extension arms for connecting rotor blades to the rotor hub; a plurality of dampers connected between a respective one of the extension arms and the rotor hub; and a fairing disposed over the rotor hub, the fairing including an inlet plenum through which air is drawn from outside the fairing into the fairing; and at least one duct for conducting the air toward the at least one of the dampers.