Turbine engine core and bypass flows having a defined fan-turbine radial distance

Patent metadata

Field	Value
Publication number	US-12163464-B2
Application number	US-202217749908-A
Country	US
Kind code	B2
Filing date	May 20, 2022
Priority date	Dec 21, 2018
Publication date	Dec 10, 2024
Grant date	Dec 10, 2024

Abstract

A gas turbine engine ( 10 ) for an aircraft comprises an engine core ( 11 ) comprising a turbine ( 19 ), a compressor ( 14 ), a core shaft ( 26 ), and a core exhaust nozzle ( 20 ), the core exhaust nozzle ( 20 ) having a core exhaust nozzle pressure ratio calculated using total pressure at the core nozzle exit ( 56 ); a fan ( 23 ) comprising a plurality of fan blades; and a nacelle ( 21 ) surrounding the fan ( 23 ) and the engine core ( 11 ) and defining a bypass duct ( 22 ), the bypass duct ( 22 ) comprising a bypass exhaust nozzle ( 18 ), the bypass exhaust nozzle ( 18 ) having a bypass exhaust nozzle pressure ratio calculated using total pressure at the bypass nozzle exit;
wherein a bypass to core ratio of:
bypass ⁢ exhaust ⁢ nozzle ⁢ pressure ⁢ ratio core ⁢ exhaust ⁢ nozzle ⁢ pressure ⁢ ratio
is configured to be in the range from 1.1 to 1.4 under aircraft cruise conditions.

First claim

The invention claimed is:

1. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, a core shaft connecting the turbine to the compressor, and a core exhaust nozzle having a core exhaust nozzle exit, the core exhaust nozzle having a core exhaust nozzle pressure ratio calculated using total pressure at the core exhaust nozzle exit under cruise conditions;
the turbine comprises a lowest pressure turbine stage having a row of rotor blades, each of the rotor blades extending radially and having a leading edge and a trailing edge;
a fan located upstream of the engine core, the fan comprising a plurality of fan blades, wherein a fan tip radius of the fan is measured between a centreline of the gas turbine engine and an outermost tip of one of the plurality of fan blades at its leading edge the fan tip radius being in the range 155 cm to 200 cm; and
a nacelle surrounding the fan and the engine core and defining a bypass duct located radially outside of the engine core, the bypass duct comprising a bypass exhaust nozzle having a bypass exhaust nozzle exit, the bypass exhaust nozzle having an outer radius measured as a radial distance between the centreline of the gas turbine engine and an inner surface of the nacelle at an axial position of a rearmost tip of the nacelle, wherein an outer bypass to fan ratio of:

the
⁢

outer
⁢

radius
⁢

of
⁢

the
⁢

bypass
⁢

exhaust
⁢

nozzle

the
⁢

fan
⁢

tip
⁢

radius

is in the range from 0.91 to 0.98, and
the bypass exhaust nozzle having a bypass exhaust nozzle pressure ratio calculated using total pressure at the bypass exhaust nozzle exit under cruise conditions;

wherein a bypass to core ratio of:

bypass
⁢

exhaust
⁢

nozzle
⁢

pressure
⁢

ratio

core
⁢

exhaust
⁢

nozzle
⁢

pressure
⁢

ratio

is configured to be in the range from 1.3 to 1.6 under aircraft cruise conditions, and

wherein a fan-turbine radius difference is defined as a radial distance between: a point on a circle swept by a radially outer tip of the trailing edge of one of the rotor blades of the lowest pressure turbine stage; and a point on a circle swept by the outermost tip of the leading edge of the one of the plurality of fan blades and a fan speed to fan-turbine radius ratio defined as:

the
⁢

maximum
⁢

take
-
off
⁢

rotational
⁢

speed
⁢

of
⁢

the
⁢

fan
⁢

(

in
⁢

rpm

)

fan
-
turbine
⁢

radius
⁢

difference
⁢

(

in
⁢

mm

)

is in the range between 1.50 rpm/mm to 1.7 rpm/mm.

2. The gas turbine engine of claim 1 , wherein the total pressure at the bypass exhaust nozzle exit is determined at an exit plane of the bypass exhaust nozzle, the exit plane extending from the rearmost tip of the nacelle towards the centreline of the gas turbine engine.

3. The gas turbine engine of claim 1 , wherein the engine core comprises a casing, and wherein the total pressure at the core exhaust nozzle exit is determined at an exit plane of the core exhaust nozzle, the exit plane extending from a rearmost point of the casing towards the centreline of the gas turbine engine.

4. The gas turbine engine of claim 1 , wherein at least one of the bypass exhaust nozzle and the core exhaust nozzle is a convergent nozzle.

5. The gas turbine engine of claim 1 , wherein a bypass ratio defined as a ratio of mass flow rate of flow through the bypass duct to mass flow rate of flow through the engine core at cruise conditions is in the range of from 13 to 18.

6. The gas turbine engine of claim 1 , wherein:
the turbine is a first turbine, the compressor is a first compressor, and the core shaft is a first core shaft;
the engine core further comprises a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor; and
the second turbine, second compressor, and second core shaft are arranged to rotate at a higher rotational speed than the first core shaft.

7. The gas turbine engine of claim 1 , wherein the fan-turbine radius difference is in a range from 900 mm to 1200 mm.

8. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, a core shaft connecting the turbine to the compressor, and a core exhaust nozzle having a core exhaust nozzle exit, the core exhaust nozzle having a core exhaust nozzle pressure ratio calculated using total pressure at the core exhaust nozzle exit under cruise conditions;
the turbine comprises a lowest pressure turbine stage having a row of rotor blades, each of the rotor blades extending radially and having a leading edge and a trailing edge;
a fan located upstream of the engine core, the fan comprising a plurality of fan blades, wherein a fan tip radius of the fan is measured between a centreline of the gas turbine engine and an outermost tip of one of the plurality of fan blades at its leading edge, the fan tip radius being in the range 155 cm to 200 cm;
a gearbox connected between the core shaft and the fan, the gearbox receiving an input from the core shaft and providing an output to drive the fan at a lower rotat

Assignees

• Rolls Royce Plc

Inventors

• Stretton Richard G
• Willmot Michael C
• Grech Nicholas

Classifications

• F02K1/00

  Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto (rocket nozzles F02K9/97) · CPC title

• F02K3/06 Primary

  with front fan · CPC title

• F05D2240/128

  Nozzles · CPC title

• F05D2220/323

  for aircraft propulsion, e.g. jet engines · CPC title

• F01D17/16

  by means of nozzle vanes · CPC title