Controlling the dynamic behavior of an aeronautical propulsion system
AssigneeSafran Aircraft Engines
InventorDidier René André ESCURE
Life of this patent
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Abstract
An aeronautical propulsion system includes a fan rotor to be driven by a fan shaft, a drive turbine that drives the fan rotor through a drive shaft about an axis of rotation, a reduction structure that couples the drive shaft and the fan shaft to drive the fan shaft at a rotation speed less than a rotation speed of the drive shaft, and bearings that center the drive shaft with respect to the axis of rotation and that include one front bearing extending upstream of a combustion chamber of the propulsion system and two rear bearings extending downstream of the combustion chamber. The position of the bearings in the propulsion system obeys a formula based on various parameters related to the bearings, the drive turbine, and the drive shaft.
Claims16
An aeronautical propulsion system comprising:
- a fan rotor configured to be driven by a fan shaft;
- a drive turbine configured to drive the fan rotor through a drive shaft about an axis of rotation;
- a reduction mechanism coupling the drive shaft and the fan shaft to drive the fan shaft at a rotation speed less than a rotation speed of the drive shaft;
- bearings configured to center the drive shaft with respect to the axis of rotation, the bearings comprising one front bearing extending upstream of a combustion chamber of the propulsion system and two rear bearings extending downstream of the combustion chamber,
- wherein a position of the bearings in the propulsion system obeys the following formula:
- C
- *
- X
-
- N
- *
- d
- 1
- 2
- R
- 11
-
- b
- *
- 1
-
- 0
- -
- 1
-
- 1
- +
- E
- 2
- ≥
- R
- m
- d
- 2
- ≥
- C
- *
- X
-
- N
- *
- d
- 1
- 2
- R
- 11
-
- b
- *
- 1
-
- 0
- -
- 1
-
- 1
- -
- E
- 1
- where:
- d2 is a distance between centers of gravity of the rear bearings of the drive shaft, in millimeters;
- Rm is an average radius of the drive turbine, in millimeters;
- XN is a redline speed of the drive shaft, in revolutions per minute;
- d1 is a distance between a center of gravity of the front bearing and a center of gravity of the rear bearing nearest to the front bearing, in millimeters;
- R11b is an average radius of the rear bearing nearest to the front bearing, in millimeters;
- and
- C=170 (mm*rpm)−1, E1=0.18 and E2=0.378.
A method for dimensioning a propulsion system comprising a reduction mechanism coupling a drive shaft and a fan rotor to drive the fan rotor at a speed less than a speed of the drive shaft, and bearings configured to center the drive shaft with respect to an axis of rotation, the bearings comprising one front bearing extending upstream of a combustion chamber of the propulsion system and two rear bearings extending downstream of the combustion chamber,
- the method comprising dimensioning the propulsion system such that a position of the bearings in the propulsion system obeys the following formula:
- C
- *
- X
-
- N
- *
- d
- 1
- 2
- R
- 11
-
- b
- *
- 1
-
- 0
- -
- 1
-
- 1
- +
- E
- 2
- ≥
- R
- m
- d
- 2
- ≥
- C
- *
- X
-
- N
- *
- d
- 1
- 2
- R
- 11
-
- b
- *
- 1
-
- 0
- -
- 1
-
- 1
- -
- E
- 1
- where:
- d2 is a distance between centers of gravity of the rear bearings of the drive shaft, in millimeters;
- Rm is an average radius of the drive turbine, in millimeters;
- XN is a redline speed of the drive shaft, in revolutions per minute;
- d1 is a distance between a center of gravity of the front bearing and a center of gravity of the rear bearing nearest to the front bearing, in millimeters;
- R11b is an average radius of the rear bearing nearest to the front bearing, in millimeters;
- and
- C=170 (mm*rpm)−1, E1=−0.18 and E2=0.378.
Dependencies are inferred from the claim text.