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US 10,436,035 B1Granted
Fan design
AssigneeROLLS-ROYCE plc
InventorsStephane M M Baralon, Christopher Benson, Benedict R Phelps
Life of this patent
Estimating the term…
Abstract
A gas turbine engine has a fan tip air angle and/or a fan blade tip air angle in a defined range to achieve improved over all performance, taking into account fan operability and/or bird strike requirements as well as engine efficiency. The defined ranges of fan tip air angle and/or a fan blade tip air angle may be particularly beneficial for gas turbine engines in which the fan is driven by a turbine through a gearbox.
Claims21
A gas turbine engine for an aircraft comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
- and
- a gearbox that receives an input from the core shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the core shaft, wherein:
- at engine cruise conditions, a fan tip air angle θ is in the range:
- 57 degrees≤θ≤62 degrees, the fan tip air angle θ being defined as:
- θ
- =
- tan
- -
- 1
-
- (
- V
- ThetaBladeTip
- Vx
- air
- )
- where:
- V
- ThetaBladeTip
- =
-
- ω
- ·
- D
- 2
-
- ;
- ω is fan rotational speed in radians/second;
- D is the diameter of the fan in meters at its leading edge;
- and
- Vxair is the mean axial velocity of the flow into the fan over the leading edge.
30 more elements
A gas turbine engine for an aircraft comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- and
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades,
- wherein, at engine cruise conditions:
- a specific thrust, defined as net engine thrust divided by mass flow rate through the engine, is in the range of from 70 Nkg−1 s to 100 Nkg−1 s;
- and
- a fan tip air angle θ is in the range:
- 57 degrees≤θ≤62 degrees, the fan tip air angle θ being defined as:
- θ
- =
- tan
- -
- 1
-
- (
- V
- ThetaBladeTip
- Vx
- air
- )
- where:
- V
- ThetaBladeTip
- =
-
- ω
- ·
- D
- 2
-
- ;
- ω is fan rotational speed in radians/second;
- D is the diameter of the fan in meters at its leading edge;
- and
- Vxair is the mean axial velocity of the flow into the fan over the leading edge.
32 more elements
A gas turbine engine for an aircraft comprising:
- an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
- a fan located upstream of the engine core, the fan comprising a plurality of fan blades;
- and
- a gearbox that receives an input from the core shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the core shaft, wherein:
- a fan blade tip angle β is defined as the angle between the tangent to the leading edge of the camber line in a cross-section through the fan blade at 90% of the blade span from the root and a projection of the axial direction onto that cross-section, and the fan blade tip angle β is in the range of from 57 to 65 degrees.
2 more elements
Dependencies are inferred from the claim text.