Rolls-royce Corporation

Richard V Brooks

Richard Geoffrey Stretton

Kenneth Franklin Udall

Arthur Laurence Rowe

Michael A Horswill

John Coupland

Fan flutter attenuators are optimized so that they occupy the minimum area of the intake duct, and so can be accommodated more easily, without significantly compromising the area available for liners targeting community noise. In such circumstances resonators for flutter frequencies are typically associated with existing acoustic liner and take the form of chambers incorporating labyrinthine cores for absorption of acoustic frequency waves or utilize Helmholtz chambers with appropriate volumes and inlet pipe aperture configurations for tuning to desired flutter frequencies to be attenuated.

Damping assembly

A duct wall of a fan casing of a gas turbine engine comprises an intake section and a containment casing, which are interconnected by bolts at flanges. An acoustic flutter damper is provided between the flanges to reduce or eliminate flutter arising in blades of the fan at certain important operating conditions. The damper provides flexibility at the connection between the intake section and the containment casing so that, in the event of detachment of a blade or a bladed fragment, the resulting deflection wave in the containment casing can be accommodated by displacement and/or deformation of the acoustic flutter damper, reducing the risk that the bolts will shear to allow the intake section and the containment casing to become detached from each other. The acoustic flutter damper may comprise a circumferential array of separate segments.

Duct wall for a fan of a gas turbine engine

A gas turbine engine () comprises a fan rotor () having a plurality of fan blades () and an apparatus () for detecting an impact on the fan blades (). The apparatus () comprises speed sensors (B) arranged to measure the speed of rotation of the fan rotor () and the turbine rotor () and to produce speed signals. A processor unit () analyses the speed signals to determine the angle of twist between the ends of the fan rotor (). The processor unit () is arranged to analyse the angle of twist to determine if the angle of twist of the fan rotor () oscillates by more than a predetermined level from an average level. The processor unit () is arranged to produce a signal indicative of an impact to at least one of the fan blades () if the angle of twist oscillates by more than the predetermined level and sends a signal to an indicator device ().

Apparatus and method for detecting an impact on a rotor blade

A gas turbine engine ( ) comprises a fan rotor ( ) having a plurality of fan blades ( ) and an apparatus ( ) for detecting damage to the fan blades ( ). The apparatus ( ) comprises a transducer ( ) arranged to detect the pressure in the gas flow around the fan blades ( ) and to produce a pressure signal. A speed sensor ( ) is arranged to measure the speed of rotation of the fan rotor ( ) and to produce a speed signal. A processor unit ( ) analyses the pressure signal and the speed signal to detect changes in the amplitude of the pressure signal, which occur at multiples of the rotational frequency of the fan rotor ( ). The changes indicate differences in pressure between the gas flow around a damaged fan blade ( ) and the gas flow around the remainder of the fan blades ( ). The processor unit ( ) sends a signal indicative of damage to a fan blade ( ), if the difference in pressure is above the predetermined level, to an indicator device ( ).

Growing community of inventors

Derby, United Kingdom

Richard V Brooks