A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.

An acoustic panel includes a front skin comprising a plurality of apertures, a back skin, and a core positioned between the front skin and the back skin. The core includes at least one primary core portion including a honeycomb structure defining a plurality of cavities extending from the front skin to the back skin. The core further includes a secondary core portion external to the at least one primary core portion and including a foam structure extending from the front skin to the back skin.

An acoustic panel includes a front skin comprising a plurality of apertures, a back skin, and a core positioned between the front skin and the back skin. The core includes at least one primary core portion including a honeycomb structure defining a plurality of cavities extending from the front skin to the back skin. The core further includes a secondary core portion external to the at least one primary core portion and including a foam structure extending from the front skin to the back skin.

An acoustic damper includes a low porosity layer section and a housing. The low porosity layer section is formed in a liner of a gas turbine combustor and has an arrangement of elongated generally S-shaped slots formed therein. The housing has a plurality of feed apertures. The housing is coupled to the low porosity layer section thereby defining a cavity such that air outside the housing is configured to flow through the apertures and through the elongated generally S-shaped slots in the low porosity layer section, thereby transforming acoustic energy into thermal energy and aiding in providing an acoustic dampening effect for the gas turbine combustor during operation thereof.

An acoustic damper includes a low porosity layer section and a housing. The low porosity layer section is formed in a liner of a gas turbine combustor and has an arrangement of elongated generally S-shaped slots formed therein. The housing has a plurality of feed apertures. The housing is coupled to the low porosity layer section thereby defining a cavity such that air outside the housing is configured to flow through the apertures and through the elongated generally S-shaped slots in the low porosity layer section, thereby transforming acoustic energy into thermal energy and aiding in providing an acoustic dampening effect for the gas turbine combustor during operation thereof.

A vibration damper for a fuel conduit of a gas turbine combustor includes a mounting portion and a damping portion. The mounting portion is secured to the fuel conduit, and the damping portion includes a stack of damping washers, a bushing on top of the stack of damping washers, a spring clip secured around the stack of damping washers and the bushing, and a shoulder bolt disposed through the bushing and the stack of damping washers and engaged to the mounting portion.

A vibration damper for a fuel conduit of a gas turbine combustor includes a mounting portion and a damping portion. The mounting portion is secured to the fuel conduit, and the damping portion includes a stack of damping washers, a bushing on top of the stack of damping washers, a spring clip secured around the stack of damping washers and the bushing, and a shoulder bolt disposed through the bushing and the stack of damping washers and engaged to the mounting portion.

A fairing for a power generation machine, the fairing comprising: a first layer comprising a metallic material; a second layer comprising a composite; and a third layer positioned between the first layer and the second layer, the third layer being configured to attenuate acoustic waves over a predetermined frequency range.

A fairing for a power generation machine, the fairing comprising: a first layer comprising a metallic material; a second layer comprising a composite; and a third layer positioned between the first layer and the second layer, the third layer being configured to attenuate acoustic waves over a predetermined frequency range.

Shape memory alloy (SMA) actuators and thermal management systems including the same. An SMA actuator includes an SMA lifting tube and a process fluid conduit configured to convey a process fluid through the SMA lifting tube. The SMA actuator assumes a conformation that is based on the temperature of the process fluid. The SMA lifting tube includes a first end and a second end configured to translate relative to the first end at least partially along a lateral direction. A thermal management system is configured to regulate a temperature of a process fluid. The thermal management system includes a heat exchanger that at least partially defines a heat transfer region, a process fluid conduit configured to convey the process fluid through the heat transfer region, and an actuator assembly including the SMA actuator. The actuator assembly is configured to selectively position the heat exchanger within a thermal management fluid flow.