Patent ID: 11879343
Assignee: ROLLS-ROYCE CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A fan assembly adapted for a gas turbine engine, the fan assembly comprising
a fan duct arranged circumferentially around a central axis,
an inlet fan comprising a plurality of fan blades that extend radially outward relative to the central axis and that are adapted to rotate about the central axis to force fan exit air toward an aft end of the fan duct,
an outlet guide vane assembly located in the fan duct axially downstream of the inlet fan and configured to adjust a direction of the fan exit air received from the plurality of fan blades, the outlet guide vane assembly including a first plurality of variable-pitch outlet guide vanes including a first variable-pitch outlet guide vane that extends radially relative to the central axis, the first variable-pitch outlet guide vane being configured to rotate to a first vane-pitch angle, and
a control system configured to rotate the first variable-pitch outlet guide vane about a first vane-pitch axis that extends radially relative to the central axis to redirect the fan exit air,
wherein the control system is configured to rotate the first plurality of variable-pitch outlet guide vanes to a first arrangement of vane-pitch angles including the first vane-pitch angle in order to (i) reduce vibratory response of the plurality of fan blades in response to the fan assembly experiencing at least one given operability condition and (ii) redirect the fan exit air and minimize intake flow distortion experienced by the inlet fan in response to at least one air flow characteristic,
wherein the control system includes a processor and a non-transitory computer readable data storage medium, wherein the control system is configured to (i) store the first arrangement as a predetermined first arrangement, (ii) store the at least one given operability condition as at least one predetermined given operability condition, and (iii) store the at least one air flow characteristic as at least one predetermined air flow characteristic in the non-transitory computer readable data storage medium, wherein the predetermined first arrangement corresponds to at least one of the at least one predetermined given operability condition and the at least one predetermined air flow characteristic, and wherein the control system is configured to rotate the first plurality of variable-pitch outlet guide vanes to the predetermined first arrangement in response to at least one of the fan assembly experiencing the at least one predetermined given operability condition and the at least one predetermined air flow characteristic being present in the inlet air entering the inlet fan or the fan exit air, and
wherein the at least one predetermined given operability condition includes a threshold inlet fan speed at which flutter begins to occur.