公开(公告)号：US20210381430A1

公开(公告)日：2021-12-09

申请号：US17331020

申请日：2021-05-26

Applicant: ROLLS-ROYCE PLC

Inventor： Matthew SILVESTER ,  Geoffrey HUGHES

IPC: F02C3/073 ,  B64D27/10 ,  F04D25/02

Abstract: A gas turbine engine for an aircraft includes a fan system having a reverse travelling wave first flap mode, Fan RTW, and including a fan located upstream of the engine core; a fan shaft; and a front engine structure arranged to support the fan shaft and having a front engine structure nodding mode comprising a pair of modes at similar, but not equal, natural frequencies in orthogonal directions; and a gearbox. An LP rotor system including the fan system and a gearbox output shaft arranged to drive the fan shaft has a first reverse whirl rotor dynamic mode, Rotor RW, and a first forward whirl rotor dynamic mode, 1FW. The engine has a maximum take-off speed, MTO. A backward whirl frequency margin of: the ⁢ ⁢ lowest ⁢ ⁢ frequency ⁢ ⁢ of ⁢ ⁢ either ⁢ ⁢ mode ⁢ ⁢ Fan ⁢ ⁢ RTW ⁢ ⁢ or ⁢ ⁢ Rotor ⁢ ⁢ RW ⁢ ⁢ at the ⁢ ⁢ MTO ⁢ ⁢ speed the ⁢ ⁢ MTO ⁢ ⁢ speed may be in the range from 15 to 50%.

公开(公告)号：US20230279814A1

公开(公告)日：2023-09-07

申请号：US17738198

申请日：2022-05-06

Applicant: ROLLS-ROYCE plc

Inventor： Matthew SILVESTER ,  Geoffrey HUGHES

IPC: F02C7/36 ,  F04D29/40 ,  B64D27/10 ,  F02C3/073 ,  F04D25/02 ,  F02K3/06

CPC classification number: F02C7/36 ,  B64D27/10 ,  F02C3/073 ,  F02K3/06 ,  F04D25/02 ,  F04D29/40 ,  F05D2220/36 ,  F05D2220/323 ,  F05D2260/96 ,  F05D2260/4031

Abstract: A gas turbine engine for an aircraft includes a fan system having a reverse travelling wave first flap mode, Fan RTW, and including a fan located upstream of the engine core; a fan shaft; and a front engine structure arranged to support the fan shaft and having a front engine structure nodding mode comprising a pair of modes at similar, but not equal, natural frequencies in orthogonal directions; and a gearbox. An LP rotor system including the fan system and a gearbox output shaft arranged to drive the fan shaft has a first reverse whirl rotor dynamic mode, Rotor RW, and a first forward whirl rotor dynamic mode, 1FW. The engine has a maximum take-off speed, MTO. A backward whirl frequency margin of:








t
h
e
 
 
l
o
w
e
s
t
 
f
r
e
q
u
e
n
c
y
 
o
f
 
e
i
t
h
e
r
 
m
o
d
e
 
F
a
n
 
R
T
W




 
o
r
 
R
o
t
o
r
 
R
W
 
a
t
 
t
h
e
 
M
T
O
 
s
p
e
e
d




t
h
e
 
M
T
O
 
s
p
e
e
d






may be in the range from 15 to 50%.

公开(公告)号：US20210381440A1

公开(公告)日：2021-12-09

申请号：US17330616

申请日：2021-05-26

Applicant: ROLLS-ROYCE plc

Inventor： Matthew SILVESTER ,  Geoffrey HUGHES

IPC: F02C7/36

Abstract: A gas turbine engine for an aircraft includes a fan system including a fan located upstream of the engine core; a fan shaft; and a front engine structure arranged to support the fan shaft and having a front engine structure nodding mode including a pair of modes at similar, but not equal, natural frequencies in orthogonal directions; and a gearbox. An LP rotor system including the fan system and a gearbox output shaft arranged to drive the fan shaft has a first forward whirl rotor dynamic mode, 1FW. The engine has a maximum take-off speed, MTO. A forward whirl frequency margin of: the ⁢ ⁢ frequency ⁢ ⁢ difference ⁢ ⁢ between ⁢ ⁢ the ⁢ ⁢ intersection ⁢ ⁢ of ⁢ ⁢ 1 ⁢ ⁢ FW ⁢ ⁢ and the ⁢ ⁢ first ⁢ ⁢ engine ⁢ ⁢ order ⁢ ⁢ line ⁢ ⁢ and ⁢ ⁢ the ⁢ ⁢ first ⁢ ⁢ engine ⁢ ⁢ order at ⁢ ⁢ the ⁢ ⁢ MTO ⁢ ⁢ speed the ⁢ ⁢ MTO ⁢ ⁢ speed is in the range from 10 to 100%.

公开(公告)号：US20220065196A1

公开(公告)日：2022-03-03

申请号：US17331384

申请日：2021-05-26

Applicant: ROLLS-ROYCE plc

Inventor： Matthew SILVESTER ,  Geoffrey HUGHES

IPC: F02K3/06 ,  F02C7/36

Abstract: A gas turbine engine having a reverse travelling wave first flap mode, Fan RTW, and including a fan located upstream of the engine core; a fan shaft; a front engine structure arranged to support the fan shaft and having a front engine structure nodding mode including a pair of modes at similar, but not equal, natural frequencies in orthogonal directions; and a gearbox. An LP rotor system including the fan system and a gearbox output shaft arranged to drive the fan shaft first reverse and first forward whirl rotor dynamic modes, Rotor RW, and 1FW. The engine has a maximum take-off speed, MTO. A mutual frequency margin of: the ⁢ ⁢ frequency ⁢ ⁢ difference ⁢ ⁢ between ⁢ ⁢ mode ⁢ ⁢ Fan ⁢ ⁢ RTW ⁢ ⁢ ⁢ ⁢ and ⁢ ⁢ mode ⁢ ⁢ Rotor ⁢ ⁢ RW ⁢ ⁢ at ⁢ ⁢ the ⁢ ⁢ MTO ⁢ ⁢ speed ⁢ ( the ⁢ ⁢ lowest ⁢ ⁢ frequency ⁢ ⁢ of ⁢ ⁢ either ⁢ ⁢ mode ⁢ ⁢ Fan ⁢ ⁢ RTW ⁢ ⁢ ⁢ ⁢ or ⁢ ⁢ Rotor ⁢ ⁢ RW ⁢ ⁢ at ⁢ ⁢ the ⁢ ⁢ MTO ⁢ ⁢ speed + the ⁢ ⁢ MTO ⁢ ⁢ speed ) is in the range from 5 to 50%.

公开(公告)号：US20210381441A1

公开(公告)日：2021-12-09

申请号：US17331989

申请日：2021-05-27

Applicant: ROLLS-ROYCE PLC

Inventor： Matthew SILVESTER ,  Geoffrey HUGHES

IPC: F02C7/36 ,  F04D29/40

Abstract: An aircraft gas turbine engine includes a fan system having a reverse traveling wave first flap mode, Fan RTW, and including a fan upstream of the engine core; a fan shaft; and a front engine structure to support the shaft and having a front engine structure nodding mode FSN including two modes at similar, but unequal, natural frequencies in orthogonal directions; and a gearbox. The engine includes a gearbox, and a gearbox output shaft to couple output of the gearbox to the fan shaft. An LP rotor system including the fan system and the gearbox output shaft has a first reverse whirl rotor dynamic mode, Rotor RW. A frequency margin of: ⁢ the ⁢ ⁢ frequency ⁢ ⁢ difference ⁢ ⁢ between ⁢ ⁢ mode ⁢ ⁢ ⁢ ⁢ FSN ⁢ ⁢ and ⁢ ⁢ the ⁢ ⁢ highest ⁢ ⁢ frequency ⁢ ⁢ of ⁢ ⁢ either ⁢ ⁢ ⁢ ⁢ synchronous ⁢ ⁢ Fan ⁢ ⁢ RTW ⁢ ⁢ or ⁢ ⁢ synchronous ⁢ ⁢ Rotor ⁢ ⁢ RW ⁢ the ⁢ ⁢ lowest ⁢ ⁢ natural ⁢ ⁢ frequency ⁢ ⁢ of ⁢ ⁢ ⁢ ⁢ the ⁢ ⁢ front ⁢ ⁢ structure ⁢ ⁢ nodding ⁢ ⁢ pair ⁢ ⁢ of ⁢ ⁢ modes is in the range from 5 to 50%.