Turbomachine and method of assembly
A turbomachine includes an annular casing and a fan disposed inside the annular casing and mounted for rotation about an axial centerline. The fan includes fan blades that extend radially outwardly toward the annular casing. The fan has an average chord fan width according to a first performance factor. The fan has a quantity of fan blades according to a second performance factor.
1 . A turbomachine for an aircraft comprising:
an annular casing; and
a fan disposed inside the annular casing and mounted for rotation about an axial centerline, the fan including a plurality of fan blades that extend radially outwardly toward the annular casing, wherein at least one fan blade of the plurality of fan blades includes:
a straight axial dovetail,
an airfoil, and
a transition section disposed between the dovetail and the airfoil,
the at least one fan blade having opposed pressure and suction sides, and further including at least one shoulder protruding from a nominal surface of a selected one of the pressure and suction sides, wherein the at least one shoulder includes a boss defining a side face, and an upper section extending radially outward from the boss and tapering inward to join the nominal surface of the selected side;
wherein the fan includes an average fan chord width of the fan blades (“c”), a diameter of the fan (“D”), a fan pressure ratio (“FPR”), and a redline corrected fan tip Mach number
(
“
M
tip
,
c
(
RL
)
”
)
according to a First Performance Factor (“FPF”),
wherein
F
P
F
=
[
c
0.15
·
D
]
/
[
[
F
P
R
-
1
0.4
]
/
M
tip
,
c
(
RL
)
]
-
1.23
,
wherein
m
1
·
[
M
tip
,
c
(
RL
)
-
1
.
1
]
+
9
.
1
4
>
FPF
>
m
2
·
[
M
tip
,
c
(
RL
)
-
1
.
1
]
,
and
wherein m 1 is equal to 9.43 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 27.02 when
M
tip
,
c
(
RL
)
is less than 1.1, and
wherein m 2 is equal to 0.87 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 3.34 when
M
tip
,
c
(
RL
)
is less than 1.1.
2 . The turbomachine of claim 1 , wherein the dovetail, airfoil, and transition section are formed as a composite layup comprising a plurality of layers of fibers embedded in a matrix.
3 . The turbomachine of claim 1 , wherein a plurality of spaces are present between adjacent fan blades of the plurality of fan blades, and wherein the fan further includes:
a rotor disk having an annular array of dovetail slots, and
an array of platforms disposed in the spaces between the adjacent fan blades, the platforms having an outer surface defining a portion of a flowpath boundary and abutting side faces of the shoulders of the adjacent blades.
4 . The turbomachine of claim 1 , wherein the at least one shoulder is integrally-formed with the remainder of the fan blade, runs in a generally axial direction, protrudes to a maximum extent at a leading edge of the fan blade, and tapers off in an axially rearward direction.
5 . The turbomachine of claim 1 , wherein:
FPF is within a range equal to or greater than −0.8 and equal to or less than 8.4;
M
tip
,
c
(
RL
)
is within a range equal to or greater than 0.8 and equal to or less than 1.5;
a ratio c/D is within a range equal to or greater than 0.1 and equal to or less than 0.3; and
FPR is within a range equal to or greater than 1.2 and equal to or less than 1.6.
6 . The turbomachine of claim 1 , wherein the turbomachine has a gear ratio within a range equal to or greater than 3.2 and equal to or less than 5.0.
7 . The turbomachine of claim 1 , wherein a ratio c/D is between 0.16 and 0.21, and the fan has between 16 and 25 fan blades.
8 . A turbomachine comprising for an aircraft comprising:
an annular casing; and
a fan disposed inside the annular casing and mounted for rotation about an axial centerline, the fan including a plurality of fan blades that extend radially outwardly toward the annular casing, wherein at least one fan blade of the plurality of fan blades includes:
a straight axial dovetail,
an airfoil, and
a transition section disposed between the dovetail and the airfoil,
the at least one fan blade having opposed pressure and suction sides, and further including at least one shoulder protruding from a nominal surface of a selected one of the pressure and suction sides, wherein the at least one shoulder includes a boss defining a side face, and an upper section extending radially outward from the boss and tapering inward to join the nominal surface of the selected side;
wherein the fan includes a fan hub-to-tip ratio (“HTR”), a fan blade count (“BC”), a fan pressure ratio (“FPR”), and a redline corrected fan tip Mach number
(
“
M
tip
,
c
(
RL
)
”
)
according to a Second Performance Factor (“SPF”),
wherein
S
P
F
=
π
4
(
1
-
H
T
R
2
)
/
(
B
C
20
)
/
(
F
P
R
-
1
0.4
)
/
M
tip
,
c
(
RL
)
-
0.97
,
wherein
m
3
·
[
M
tip
,
c
(
RL
)
-
1.1
]
+
2.52
>
SPF
>
m
4
·
[
M
tip
,
c
(
RL
)
-
1.1
]
wherein m 3 is equal to 3.17, and
wherein m 4 is equal to 0.41 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 0.55 when
M
tip
,
c
(
RL
)
is less than 1.1.
9 . The turbomachine of claim 8 , wherein the dovetail, airfoil, and transition section are formed as a composite layup comprising a plurality of layers of fibers embedded in a matrix.
10 . The turbomachine of claim 8 , wherein a plurality of spaces are present between adjacent fan blades of the plurality of fan blades, and wherein the fan further includes:
a rotor disk having an annular array of dovetail slots, and
an array of platforms disposed in the spaces between the adjacent fan blades, the platforms having an outer surface defining a portion of a flowpath boundary and abutting side faces of the shoulders of the adjacent blades.
11 . The turbomachine of claim 8 , wherein the at least one shoulder is integrally-formed with the remainder of the fan blade, runs in a generally axial direction, protrudes to a maximum extent at a leading edge of the fan blade, and tapers off in an axially rearward direction.
12 . The turbomachine of claim 8 , wherein:
SPF is within a range equal to or greater than 0.087 and equal to or less than 2.4;
M
tip
,
c
(
RL
)
is within a range equal to or greater than 0.8 and equal to or less than 1.5;
HTR is within a range equal to or greater than 0.2 and equal to or less than 0.4;
FPR is within a range equal to or greater than 1.2 and equal to or less than 1.6; and
BC is within a range equal to or greater than 3 and equal to or less than 18.
13 . The turbomachine of claim 8 , wherein the turbomachine has a gear ratio within a range equal to or greater than 3.2 and equal to or less than 5.0.
14 . A turbomachine for an aircraft comprising:
an annular casing; and
a fan disposed inside the annular casing and mounted for rotation about an axial centerline, the fan including a plurality of fan blades that extend radially outwardly toward the annular casing, wherein at least one fan blade of the plurality of fan blades including:
a straight axial dovetail,
an airfoil, and
a transition section disposed between the dovetail and the airfoil,
the at least one fan blade having opposed pressure and suction sides, and further including at least one shoulder protruding from a nominal surface of a selected one of the pressure and suction sides, wherein the at least one shoulder includes a boss defining a side face, and an upper section extending radially outward from the boss and tapering inward to join the nominal surface of the selected side;
wherein the fan includes an average fan chord width of the fan blades (“c”), a diameter of the fan (“D”), a fan pressure ratio (“FPR”), and a redline corrected fan tip Mach number
(
“
M
tip
,
c
(
RL
)
”
)
according to a First Performance Factor (“FPF”),
wherein
F
P
F
=
[
c
0.15
·
D
]
/
[
[
F
P
R
-
1
0.4
]
/
M
tip
,
c
(
RL
)
]
-
1.23
,
wherein
m
1
·
[
M
tip
,
c
(
RL
)
-
1.1
]
+
9.14
>
FPF
>
m
2
·
[
M
tip
,
c
(
RL
)
-
1.1
]
,
and
wherein m 1 is equal to 9.43 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 27.02 when
M
tip
,
c
(
RL
)
is less than 1.1, and
wherein m 2 is equal to 0.87 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 3.34 when
M
tip
,
c
(
RL
)
is less than 1.1;
wherein the fan includes a fan hub-to-tip ratio (“HTR”), a fan blade count (“BC”), the fan pressure ratio (“FPR”), and the redline corrected fan tip Mach number
(
“
M
tip
,
c
(
RL
)
”
)
according to a Second Performance Factor (“SPF”),
wherein
S
P
F
=
π
4
(
1
-
H
T
R
2
)
/
(
B
C
20
)
/
(
F
P
R
-
1
0.4
)
/
M
tip
,
c
(
RL
)
-
0.97
,
wherein
m
3
·
[
M
tip
,
c
(
RL
)
-
1.1
]
+
2.52
>
SPF
>
m
4
·
[
M
tip
,
c
(
RL
)
-
1.1
]
wherein m 3 is equal to 3.17, and
wherein m 4 is equal to 0.41 when
M
tip
,
c
(
RL
)
is greater than or equal to 1.1 and is equal to 0.55 when
M
tip
,
c
(
RL
)
is less than 1.1.
15 . The turbomachine of claim 14 , wherein the dovetail, airfoil, and transition section are formed as a composite layup comprising a plurality of layers of fibers embedded in a matrix.
16 . The turbomachine of claim 14 , wherein a plurality of spaces are present between adjacent fan blades of the plurality of fan blades, and wherein the fan further includes:
a rotor disk having an annular array of dovetail slots, and
an array of platforms disposed in the spaces between the adjacent fan blades, the platforms having an outer surface defining a portion of a flowpath boundary and abutting side faces of the shoulders of the adjacent blades.
17 . The turbomachine of claim 14 , wherein the at least one shoulder is integrally-formed with the remainder of the fan blade, runs in a generally axial direction, protrudes to a maximum extent at a leading edge of the fan blade, and tapers off in an axially rearward direction.
18 . The turbomachine of claim 14 , wherein:
FPF is within a range equal to or greater than −0.8 and equal to or less than 8.4;
SPF is within a range equal to or greater than 0.087 and equal to or less than 2.4;
M
tip
,
c
(
RL
)
is within a range equal to or greater than 0.8 and equal to or less than 1.5; and
FPR is within a range equal to or greater than 1.2 and equal to or less than 1.6.
19 . The turbomachine of claim 14 , wherein:
a ratio c/D is within a range equal to or greater than 0.1 and equal to or less than 0.3;
HTR is within a range equal to or greater than 0.2 and equal to or less than 0.4; and
BC is within a range equal to or greater than 3 and equal to or less than 18.
20 . The turbomachine of claim 14 , wherein the turbomachine has a gear ratio within a range equal to or greater than 3.2 and equal to or less than 5.0.