GB2064005A - Air Intake to Ducted Fan Engine - Google Patents

Air Intake to Ducted Fan Engine Download PDF

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Publication number
GB2064005A
GB2064005A GB7940383A GB7940383A GB2064005A GB 2064005 A GB2064005 A GB 2064005A GB 7940383 A GB7940383 A GB 7940383A GB 7940383 A GB7940383 A GB 7940383A GB 2064005 A GB2064005 A GB 2064005A
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GB
United Kingdom
Prior art keywords
gas turbine
turbine engine
ducted fan
air intake
fan
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7940383A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rolls Royce PLC
Original Assignee
Rolls Royce PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rolls Royce PLC filed Critical Rolls Royce PLC
Priority to GB7940383A priority Critical patent/GB2064005A/en
Publication of GB2064005A publication Critical patent/GB2064005A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
    • F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

In order to improve ground clearance below an underwing mounted engine, the air intake structure (24) is made elliptical, the minor axis (D) being arranged substantially vertical. <IMAGE>

Description

SPECIFICATION Ducted Fan, Gas Turbine Engine This invention relates to a ducted fan, gas turbine engine.
More particularly, the invention relates to a ducted fan, gas turbine engine adapted for support from the underside of an aircraft wing.
Ducted fan gas turbine engines, by virtue of their relatively large overall diametral dimensions, are normally used to power those aircraft which the experts recognise as large transports. The limitation of use such size imposes, is brought about by the amount of available ground clearance i.e. the space between the bottom of the engine and the ground during take off and landing of an aircraft powered by such engines.
The present invention seeks to provide a ducted fan gas turbine engine having a wider scope of application in the control of powering aircraft, than has been the norm.
According to the present invention, a ducted fan gas turbine engine comprises a primary air intake structure, the shape of which is substantially elliptical at its upstream end and changes progressively, to circular at its interface with the fan casing of the ducted fan, gas turbine engine and includes mounting means suitable for mounting the ducted fan gas turbine engine from under an aircraft wing, said mounting means being arranged so as to support said ducted fan, gas turbine engine such that the major axis of its elliptical air intake structure is substantially horizontal.
The invention will now be described, by way of example and by reference to the accompanying drawings in which: Figure 1 is an axial cross-sectional view of a ducted fan, gas turbine engine in accordance with the invention, Figure 2 is a view in the direction of arrow 2 in Figure 1, and Figure 3 is a cross-sectional part view on the line 3-3 of Figure 2.
Referring to Figure 1. A ducted fan, gas turbine engine 10 is suspended via a pylon 12, from the underside of an aircraft wing 14.
Ducted fan, gas turbine engine 10 includes a stage of fan blades (not shown) in a fan casing 1 6 and, a core gas generator 1 8 with which to drive the fan stage. The fan casing 1 6 and a substantial portion of core gas generator 1 8 are enclosed in a streamlined cowl 20, which together with the outer surface of core gas generator 18, forms an annular fan nozzle 22. Cowl 20 also provides a primary air intake 24, for both fan and core gas generator 1 8.
Figure 1 shows ducted fan, gas turbine engine 10 in the position it adopts relative to the ground 28, when mounted as hereinbefore described on the wing of an aircraft. An under carriage wheel 26 of the aircraft is also shown, positioned with respect to the ducted fan, gas turbine engine 10, in a manner similar to the real situation.
As can be seen, the space 'A' between cowl 20 and the ground 28, is minimal. Even so, such space is only obtainable, by reducing both the outer profile of cowl 20 and its inner profile 32. It is necessary to maintain the correct overall profile at the upstream end of cowl 20, having regard to the necessity for ensuring a smooth flow of ambient air over the inner and outer surfaces of the air intake 24 and, the varying volumetric flow rate, which variance is brought about by changing engine operating conditions. However, the effective narrowing of the overall profile of air intake 24 as seen in Figure 1, would have a detrimental effect on the diameter 'D' of the air intake throat, by way of reducing the area thereof and that, in turn, would cause the air intake to choke under certain operating conditions.
Therefore, whilst diameter 'D' as viewed in Figure 1 is reduced from the norm for a given engine, the air intake structure is also shaped as viewed in Figure 2 i.e. as an ellipse, wherein diameter 'D' is reduced to the minor axis but the dimension 'M' of the major axis in the plane of the throat, is of such magnitude, that the throat area is restored.
As is known in the art, known air intakes have a highlight dimension 'H'. The highlight is the upstream extremity of the intake lip and, in the present invention, the lip surface between the highlight and the throat, consists of a quarter ellipse 33, through the major and minor axes thereof may vary around the lip. In the present invention this feature is retained over the full periphery of the lip of intake 24, by making the highlight profile elliptical, the axes of the ellipse being coincident with the axes of the elliptical throat, but upstream thereof.
Referring to Figure 3. The widening of the air intake 24, in a horizontal or near horizontal plane to form the major axis of the ellipse, necessitates the shaping of the outer surface of cowl 20 such that the ambient airflow thereover, is smooth.
There results a space 34 which can be utilised for the carrying of accessory drive units and other such ancillary equipment, indicated by the numeral 36.
It is important to ensure that, the duct formed by air intake 24 achieves a given diffusion rate so as to minimise losses and in the present example, this requirement results in an intake which has a reducing cross-section.
Claims
1. A ducted fan gas turbine engine comprising a primary air intake structure, the shape of which is substantially elliptical at its upstream end and changes progressively, to circular at its interface with the fan casing of the ducted fan, gas turbine engine and including mounting means suitable for mounting it from under, an aircraft wing, said mounting means being arranged so as to support said ducted fan gas turbine engine such that the major axis of its elliptical air intake structure is substantially horizontal.
2. A ducted fan, gas turbine engine as claimed in claim 1, wherein said air intake structure defines a duct having a cross-sectional area
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ducted Fan, Gas Turbine Engine This invention relates to a ducted fan, gas turbine engine. More particularly, the invention relates to a ducted fan, gas turbine engine adapted for support from the underside of an aircraft wing. Ducted fan gas turbine engines, by virtue of their relatively large overall diametral dimensions, are normally used to power those aircraft which the experts recognise as large transports. The limitation of use such size imposes, is brought about by the amount of available ground clearance i.e. the space between the bottom of the engine and the ground during take off and landing of an aircraft powered by such engines. The present invention seeks to provide a ducted fan gas turbine engine having a wider scope of application in the control of powering aircraft, than has been the norm. According to the present invention, a ducted fan gas turbine engine comprises a primary air intake structure, the shape of which is substantially elliptical at its upstream end and changes progressively, to circular at its interface with the fan casing of the ducted fan, gas turbine engine and includes mounting means suitable for mounting the ducted fan gas turbine engine from under an aircraft wing, said mounting means being arranged so as to support said ducted fan, gas turbine engine such that the major axis of its elliptical air intake structure is substantially horizontal. The invention will now be described, by way of example and by reference to the accompanying drawings in which: Figure 1 is an axial cross-sectional view of a ducted fan, gas turbine engine in accordance with the invention, Figure 2 is a view in the direction of arrow 2 in Figure 1, and Figure 3 is a cross-sectional part view on the line 3-3 of Figure 2. Referring to Figure 1. A ducted fan, gas turbine engine 10 is suspended via a pylon 12, from the underside of an aircraft wing 14. Ducted fan, gas turbine engine 10 includes a stage of fan blades (not shown) in a fan casing 1 6 and, a core gas generator 1 8 with which to drive the fan stage. The fan casing 1 6 and a substantial portion of core gas generator 1 8 are enclosed in a streamlined cowl 20, which together with the outer surface of core gas generator 18, forms an annular fan nozzle 22. Cowl 20 also provides a primary air intake 24, for both fan and core gas generator 1 8. Figure 1 shows ducted fan, gas turbine engine 10 in the position it adopts relative to the ground 28, when mounted as hereinbefore described on the wing of an aircraft. An under carriage wheel 26 of the aircraft is also shown, positioned with respect to the ducted fan, gas turbine engine 10, in a manner similar to the real situation. As can be seen, the space 'A' between cowl 20 and the ground 28, is minimal. Even so, such space is only obtainable, by reducing both the outer profile of cowl 20 and its inner profile 32. It is necessary to maintain the correct overall profile at the upstream end of cowl 20, having regard to the necessity for ensuring a smooth flow of ambient air over the inner and outer surfaces of the air intake 24 and, the varying volumetric flow rate, which variance is brought about by changing engine operating conditions. However, the effective narrowing of the overall profile of air intake 24 as seen in Figure 1, would have a detrimental effect on the diameter 'D' of the air intake throat, by way of reducing the area thereof and that, in turn, would cause the air intake to choke under certain operating conditions. Therefore, whilst diameter 'D' as viewed in Figure 1 is reduced from the norm for a given engine, the air intake structure is also shaped as viewed in Figure 2 i.e. as an ellipse, wherein diameter 'D' is reduced to the minor axis but the dimension 'M' of the major axis in the plane of the throat, is of such magnitude, that the throat area is restored. As is known in the art, known air intakes have a highlight dimension 'H'. The highlight is the upstream extremity of the intake lip and, in the present invention, the lip surface between the highlight and the throat, consists of a quarter ellipse 33, through the major and minor axes thereof may vary around the lip. In the present invention this feature is retained over the full periphery of the lip of intake 24, by making the highlight profile elliptical, the axes of the ellipse being coincident with the axes of the elliptical throat, but upstream thereof. Referring to Figure 3. The widening of the air intake 24, in a horizontal or near horizontal plane to form the major axis of the ellipse, necessitates the shaping of the outer surface of cowl 20 such that the ambient airflow thereover, is smooth. There results a space 34 which can be utilised for the carrying of accessory drive units and other such ancillary equipment, indicated by the numeral 36. It is important to ensure that, the duct formed by air intake 24 achieves a given diffusion rate so as to minimise losses and in the present example, this requirement results in an intake which has a reducing cross-section. Claims
1. A ducted fan gas turbine engine comprising a primary air intake structure, the shape of which is substantially elliptical at its upstream end and changes progressively, to circular at its interface with the fan casing of the ducted fan, gas turbine engine and including mounting means suitable for mounting it from under, an aircraft wing, said mounting means being arranged so as to support said ducted fan gas turbine engine such that the major axis of its elliptical air intake structure is substantially horizontal.
2. A ducted fan, gas turbine engine as claimed in claim 1, wherein said air intake structure defines a duct having a cross-sectional area which contracts in a direction from its upstream end, to its interface with said fan casing.
3. A ducted fan, gas turbine engine as claimed in claim 1 or claim 2, wherein said elliptical upstream end has a peripheral lip so shaped as to provide a quarter ellipse, the major and minor axes of which may vary around the lip.
4. A ducted fan, gas turbine engine substantially as described in this specification and with reference to the drawings.
GB7940383A 1979-11-22 1979-11-22 Air Intake to Ducted Fan Engine Withdrawn GB2064005A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7940383A GB2064005A (en) 1979-11-22 1979-11-22 Air Intake to Ducted Fan Engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7940383A GB2064005A (en) 1979-11-22 1979-11-22 Air Intake to Ducted Fan Engine

Publications (1)

Publication Number Publication Date
GB2064005A true GB2064005A (en) 1981-06-10

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0241404A2 (en) * 1986-04-11 1987-10-14 United Technologies Corporation Gas turbine engine nacelle
EP0515263A1 (en) * 1991-05-23 1992-11-25 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Thrust reverser for high by-pass ratio turbofan
GB2259115A (en) * 1991-08-28 1993-03-03 Gen Electric Aircraft engine nacelle profile
FR2680831A1 (en) * 1991-08-28 1993-03-05 Gen Electric PROCESS FOR ESTABLISHING THE ENTRY PROFILE OF THE NACELLE OF AN AIRPLANE GAS TURBINE ENGINE AND INTAKE OF THE NACELLE AS WELL AS NACELLE OBTAINED USING THIS PROCESS.
EP2030892A1 (en) 2007-08-30 2009-03-04 Snecma Suspension pylon for an engine beneath an aircraft wing
FR2926536A1 (en) * 2008-01-23 2009-07-24 Snecma Sa ATTACHING A PROPULSIVE SYSTEM TO A STRUCTURE ELEMENT OF AN AIRCRAFT
US8418953B2 (en) 2008-07-24 2013-04-16 Rolls-Royce Plc Gas turbine engine nacelle
EP3581498A1 (en) * 2018-06-15 2019-12-18 Rolls-Royce plc Gas turbine engine
GB2575811A (en) * 2018-07-23 2020-01-29 Airbus Operations Ltd Aircraft engine nacelle
EP3865405A1 (en) * 2020-02-13 2021-08-18 Rolls-Royce plc Nacelle for gas turbine engine and aircraft comprising the same
CN113562183A (en) * 2021-09-07 2021-10-29 北京航空航天大学 Heat dissipation and vibration reduction system of engine direct-drive hybrid power device for unmanned aerial vehicle

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0241404A2 (en) * 1986-04-11 1987-10-14 United Technologies Corporation Gas turbine engine nacelle
EP0241404A3 (en) * 1986-04-11 1988-07-27 United Technologies Corporation Gas turbine engine nacelle
EP0515263A1 (en) * 1991-05-23 1992-11-25 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "Snecma" Thrust reverser for high by-pass ratio turbofan
FR2676780A1 (en) * 1991-05-23 1992-11-27 Snecma THRUST INVERTER FOR TURBOSOUFFLANTE WITH VERY HIGH DILUTION RATE.
US5255510A (en) * 1991-05-23 1993-10-26 Societe Nationale D'etude Et De Construction De Moteurs D'aviation "S.N.E.C.M.A." Thrust reverser for a high-bypass ratio turbofan engine
GB2259115A (en) * 1991-08-28 1993-03-03 Gen Electric Aircraft engine nacelle profile
FR2680830A1 (en) * 1991-08-28 1993-03-05 Gen Electric PROCESS FOR IMPROVING THE PERFORMANCE CHARACTERISTICS OF AN AIRCRAFT TURBINE ENGINE NACELLE AND NACELLE AS WELL AS NACELLE ENTRY OBTAINED USING THIS PROCESS.
FR2680831A1 (en) * 1991-08-28 1993-03-05 Gen Electric PROCESS FOR ESTABLISHING THE ENTRY PROFILE OF THE NACELLE OF AN AIRPLANE GAS TURBINE ENGINE AND INTAKE OF THE NACELLE AS WELL AS NACELLE OBTAINED USING THIS PROCESS.
US8240600B2 (en) 2007-08-30 2012-08-14 Snecma Pylon for suspending an engine beneath an aircraft wing
EP2030892A1 (en) 2007-08-30 2009-03-04 Snecma Suspension pylon for an engine beneath an aircraft wing
FR2920408A1 (en) * 2007-08-30 2009-03-06 Snecma Sa PYLONE OF SUSPENSION OF AN ENGINE UNDER AN AIRCRAFT WING
RU2469916C2 (en) * 2007-08-30 2012-12-20 Снекма Engine suspension pylon
US8827203B2 (en) 2008-01-23 2014-09-09 Snecma Connecting a propulsion system to a structural element of an aircraft
EP2082960A1 (en) * 2008-01-23 2009-07-29 Snecma Attachment of a propulsion system to an aircraft structural element
FR2926536A1 (en) * 2008-01-23 2009-07-24 Snecma Sa ATTACHING A PROPULSIVE SYSTEM TO A STRUCTURE ELEMENT OF AN AIRCRAFT
US8418953B2 (en) 2008-07-24 2013-04-16 Rolls-Royce Plc Gas turbine engine nacelle
EP3581498A1 (en) * 2018-06-15 2019-12-18 Rolls-Royce plc Gas turbine engine
US11421592B2 (en) 2018-06-15 2022-08-23 Rolls-Royce Plc Gas turbine engine
GB2575811A (en) * 2018-07-23 2020-01-29 Airbus Operations Ltd Aircraft engine nacelle
US11772806B2 (en) 2018-07-23 2023-10-03 Airbus Operations Limited Aircraft engine nacelle with an aft end major axis substantially parallel to the leading edge of a wing
EP3865405A1 (en) * 2020-02-13 2021-08-18 Rolls-Royce plc Nacelle for gas turbine engine and aircraft comprising the same
US11408306B2 (en) 2020-02-13 2022-08-09 Rolls-Royce Plc Nacelle for gas turbine engine and aircraft comprising the same
CN113562183A (en) * 2021-09-07 2021-10-29 北京航空航天大学 Heat dissipation and vibration reduction system of engine direct-drive hybrid power device for unmanned aerial vehicle
CN113562183B (en) * 2021-09-07 2023-08-04 北京航空航天大学 Heat dissipation and vibration reduction system of engine direct-drive type hybrid power device for unmanned aerial vehicle

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