Gas Turbine Engine Inlet Wall Design

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(12) United States Patent (lo) US 9,291,101 B2

Patent No.:

Florea et al. (45) Date of Patent : Mar. 22, 2016

(54) GAS TURBINE ENGINE INLET WALL (58) Field of Classification Search DESIGN CPC .... B64D 33/02; B64D 29/06; B64D 2241/00; YIOT 137/0536 (71) Applicant: UNITED TECHNOLOGIES USPC ................... 244/53 B, 54; 137/15.1; 181/214 CORPORATION, Hartford, CT (US) See application file for complete search history.

(56) References Cited (72) Inventors: Razvan Virgil Florea, Mancheser, CT (US); Claude G. Matalanis, U.S. PATENT DOCUMENTS Longmeadow, MA (US); Mark B.

Stucky, Glastonbury, CT (US) 3,583,661 A * 6/1971 Stake .......................... 244/53 B 4,787,421 A * 11/1988 Yu ................................. 138/178 (73) Assignee: United Technologies Corporation, 5,105,615 A * 4/1992 Herzog ........................... 60/803 5,150,571 A * 9/1992 Herzog ........................ 60/200.1 Hartford, CT (US) 5,915,403 A * 6/1999 McConachie et al........ 137/15.1 7,631,836 132 * 12/2009 Lebas ......................... 244/53 B (*) Notice: Subject to any disclaimer, the term of this 7,784,732 132 * 8/2010 Owens et al . ............... 244/53 B patent is extended or adjusted under 35 8,096,131 132 1/2012 Ziaei U.S.C. 154(b) by 52 days. 8,262,780 132 9/2012 Smithies et al.

2005/0258307 Al* 11/2005 Lebas ......................... 244/53 B 2008/0164378 Al* 7/2008 Owens et al . ............... 244/53 B (21) Appl. No.: 14/ 185,045 (Continued) (22) Filed: Feb. 20, 2014 FOREIGN PATENT DOCUMENTS (65) Prior Publication Data EP 1243782 132 * 7/2013 US 2015/0122952 Al May 7, 2015 FR 2680830 Al * 3/1993 WO W02008017567 Al * 2/2008 ............. B64D 33/02 Primary Examiner Benjamin P Lee Related U.S. Application Data (74) Attorney, Agent, or Firm Carlson, Gaskey & Olds, PC (60) Provisional application No. 61/770,506, filed on Feb.

28, 2013.

(57) ABSTRACT A gas turbine engine has an inlet duct formed to have a shape (51) Int. Cl.

with a first ellipse in one half and a second ellipse in a second B64D 33102 (2006.01) half. The second half has an upstream most end which is F02C 7104 (2006.01) smaller than the first ellipse. The inlet duct has a surface B64D 27120 (2006.01) defining the second ellipse which curves away from the first (52) U.S. Cl.

ellipse, such that the second ellipse is larger at an intermediate CPC . F02C 7104 (2013.01); B64D 27120 (2013.01); location. The second ellipse is even larger at a downstream B64D 33102 (2013.01); B64D 203310286 end of the inlet duct leading into a fan.

(2013.01); F05D 2220136 (2013.01); F05D 2250114 (2013.01); YIOT 13710536 (2015.04) 10 Claims, 2 Drawing Sheets ";k 144

US 9,291,101 B2

Page 2 2012/0138736 At * 6/2012 Cazals et al ..................... 244/54 (56) References Cited 2015/0030445 At * 1/2015 Gonidec et at ................ 415/220 U.S. PATENT DOCUMENTS 2015/0030446 At * 1/2015 Gonidec et at ................ 415/220 2010/0108802 At * 5/2010 Marche et al . .................. 244/54 2011/0108676 At * 5/2011 Colaprisco et al. ......... 244/53 B * cited by examiner

Mar. 22 , Sheet 1 of 2 291,101 B2 U.S. Patent 2016 US 9 , 20~ 50 ~ f 24 24-,- 0 , 'vv FIG.2 ~ 40 2% -40 ENGINE AXIS p H - ~ AIP `32

RUB FIG.3A

Patent Mar. 22, 2016 Sheet 2 of 2 9,291,101 B2

U.S. US

FIG.3C

L 140 340

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US 9,291,101 B2

GAS TURBINE ENGINE INLET WALL In another featured embodiment, a blended wing aircraft DESIGN has a blended wing fuselage and at least one embedded gas turbine engine in the fuselage. The gas turbine engine has an CROSS-REFERENCE TO RELATED inlet duct formed to have a first ellipse in one half and a APPLICATION 5 second ellipse in a second half. The second half has an upstream most end which is smaller than the first ellipse. The This application claims priority to U.S. Provisional Appli- inlet duct has a surface defining the second ellipse which cation No. 61/770,506, filed Feb. 28, 2013.

curves away from the first ellipse, such that the second ellipse is larger at an intermediate location. The second ellipse is STATEMENT REGARDING FEDERALLY even larger at a downstream end of the inlet duct leading into SPONSORED RESEARCH OR DEVELOPMENT a fan.

In another embodiment according to any of the previous This invention was made with government support under embodiments, a center of the inlet duct cross-section is Contract No. NNCO7CB59C, awarded by NASA. The Gov- 15 defined between the first and second ellipses and, a distance ernment has certain rights in this invention.

between the center and the surface defining the second ellipse increasing as one moves further into the inlet duct and toward BACKGROUND the fan.

In another embodiment according to any of the previous This application relates to an inlet wall design for use in an embodiments, a vertical semi-axis of the first ellipse is gen- embedded gas turbine engine.

erally constant from the upstream end to the downstream end.

Gas turbine engines are known and typically include a fan In another embodiment according to any of the previous delivering air into a bypass duct and into a core engine. In the core engine the air is compressed at a compressor and then embodiments, the first ellipse is in a vertically upper half of mixed with fuel and ignited in a combustion section. Products the inlet duct.

of the combustion pass downstream over turbine rotors, driv- 25 In another embodiment according to any of the previous ing them to rotate.

embodiments, the first ellipse is in a vertically lower half of Gas turbine engines have historically been mounted on a the inlet duct.

tail or beneath the wings of an aircraft. However, a next These and other features may be best understood from the generation of aircraft seeks to dramatically increase fuel effi- following drawings and specification.

ciency, reduce emissions, and decrease fuel burn. A design for such aircraft utilizes a blended wing design wherein the body BRIEF DESCRIPTION OF THE DRAWINGS and wing merge smoothly into each other. Such designs have typically been proposed with embedded engines, which are FIG. 1 shows a blended wing aircraft.

mounted within a fuselage or body of the aircraft. FIG. 2 shows an inlet duct for a gas turbine engine as may In such an engine, the area upstream of an inlet to the 35 be included in the FIG. 1 embodiment.

engine is different on circumferential locations adjacent to the FIG. 3A shows a first geometric consideration for an inlet body than at locations spaced away from the body. A bound- duct.

ary layer or area of low momentum air will be formed leading FIG. 3B shows another dimension of the inlet duct.

into the inlet and the fan at circumferential locations associ- FIG. 3C shows a graph of one inlet duct design.

ated with the body. 40 FIG. 4A shows the inlet duct at an upstream most location.

FIG. 4B shows the inlet duct at an intermediate location.

SUMMARY FIG. 4C shows the inlet duct immediately upstream of a fan.

In a featured embodiment, a gas turbine engine has an inlet FIG. 5 schematically shows an engine.

duct formed to have a shape with a first ellipse in one half and 45 FIG. 6 shows a second inlet duct.

a second ellipse in a second half. The second half has an upstream most end which is smaller than the first ellipse. The DETAILED DESCRIPTION inlet duct has a surface defining the second ellipse which curves away from the first ellipse, such that the second ellipse An aircraft 20 is illustrated in FIG.1 having a blended wing is larger at an intermediate location. The second ellipse is 50 body or fuselage 22 and a plurality of embedded gas turbine even larger at a downstream end of the inlet duct leading into engines 24. As known, the embedded gas turbine engines 24 a fan. include a fan at an upstream location delivering air into a In another embodiment according to the previous embodi- compressor and into a bypass duct. The air is mixed with fuel ment, a center of the inlet duct cross-section is defined and ignited in a combustor downstream of the compressor and between the first and second ellipses and, a distance between 55 products of that combustion pass downstream over turbine the center and the surface defining the said second ellipse rotors driving them to rotate.

increasing as one moves further into the inlet duct and toward There are challenges with regard to the embedded gas the fan. turbine engines 24. As an example, as shown in FIG. 2, an In another embodiment according to any of the previous upstream most end 100 of an embedded gas turbine engine 24 embodiments, a vertical semi-axis of the first ellipse is gen- 60 will sit on the fuselage 22. There will be a boundary layer erally constant from the upstream end to the downstream end. leading into a bottom surface 32 of an inlet duct for the engine In another embodiment according to any of the previous 24. As shown, in this design a shape of the bottom or lower embodiments, the first ellipse is in a vertically upper half of surface 32 is closer to a horizontal shape and an upper or top the inlet duct. surface 30 is closer to a cylindrical shape.

In another embodiment according to any of the previous 65 Applicant has designed the shape of the inlet duct by uti- embodiments, the first ellipse is in a vertically lower half of lizing ellipses and optimizing the curves, lengths and shape of the inlet duct. the overall duct.

US 9,291,101 B2

3 4

As shown in FIG. 3A, the shape of inlet duct 40 may be a invention. For that reason, the following claims should be studied to determine the true scope and content of this inven- super ellipse, having a first ellipse 44 at an upper surface or tion.

spaced away from the fuselage 22 and a second ellipse 42 at The invention claimed is: a lower portion or spaced adjacent to the fuselage 22. A center 5 1. A gas turbine engine comprising: line 34 is defined to separate ellipses 42 and 44. A formula for an inlet duct formed to have a shape with a first set of ellipse calculating the shape of the ellipses may be: sections along one longitudinal half and a second set of ellipse sections along a second longitudinal half, with [X/aj'+[Y/bp— 1 said second set of ellipse sections having an upstream In this formula a and b are constants (known as ellipse most end which is smaller in area than an area of an upstream most end of said first set of ellipse sections, semi-axes) corresponding to a half-width of the inlet and a and said inlet duct having a surface defining said second height derived from the center line 34 and the upper/lower set of ellipse sections which curves away from said first walls respectively. The constants p and q are exponents which set of ellipse sections, such that said second set of ellipse shape the ellipses. The values of the constants for each quarter sections has a larger area at an intermediate location, and of a super ellipse are a function of the cross-sectional area, 15 said second set of ellipse sections has an even larger area which varies linearly as a function of axial position.

at a downstream end of said inlet duct leading into a fan.

FIG. 3B shows the inlet duct 40 varying over an axial 2. The gas turbine engine as set forth in claim 1, wherein a length. As shown, the centroid C or line 34 is spaced below a center of the inlet duct cross-section is defined between said central axis of the engine X. As can be appreciated, the bottom first and second sets of ellipse sections and, a distance surface 32 curves away from the upper surface 30. The ver- between said center and said surface defining said second set tical ellipse semi-axis corresponding to upper surface 30 var- of ellipse sections increasing as one moves further into said ies linearly, with the axial position, while the vertical ellipse inlet duct and toward said fan.

semi-axis corresponding to lower surface 32 can be seen to 3. The gas turbine engine as set forth in claim 2, wherein a expand away from the center C as one moves into the inlet vertical semi-axis of said first set of ellipse sections is gener- duct 40.

25 ally constant from said upstream end to said downstream end.

FIG. 3C graphically shows the location of the center 34, the 4. The gas turbine engine as set forth in claim 3, wherein bottom surface 32, and the upper or top surface 30 as one said first set of ellipse sections is in a vertically upper half of moves further into the engine, or locations L. As can be said inlet duct.

appreciated, the vertical ellipse semi-axes corresponding to 5. The gas turbine engine as set forth in claim 3, wherein surfaces 30 and 32 generally vary linearly with the axial said first set of ellipse sections is in a vertically lower half of position.

said inlet duct.

As shown in FIG. 4A, at the inlet end 140 of the inlet duct, 6. A blended wing aircraft comprising: the super ellipse has a very small area lower ellipse 142 and an a blended wing fuselage and at least one embedded gas upper ellipse 144, which is of a much larger area. This may be turbine engine in said fuselage; and at the upstream most point on the inlet duct and immediately 35 said gas turbine engine having an inlet duct formed to have downstream of the fuselage 22.

a first set of ellipse sections along one longitudinal half FIG. 4B shows another location 240 which is somewhat and a second set of ellipse sections in a second longitu- intermediate in the duct, and wherein the lower ellipse 242 dinal half, with said second set of ellipse sections having has a much larger area than it was in the FIG. 4A. The ellipse an upstream most end which is smaller in area than an 244 may be generally the same as ellipse 144.

area of an upstream most end said first set of ellipse FIG. 4C shows a downstream location 340 wherein the sections, and said inlet duct having a surface defining ellipses 342 and 344 are generally equal in area. Immediately said second set of ellipse sections which curves away downstream of this location would be the fan, which is shown from said first set of ellipse sections, such that said schematically in FIG. 5 at 200. A bypass duct B is shown. As second set of ellipse sections has a larger area at an known, a core engine including compressor 202, combustion 45 intermediate location, and said second set of ellipse section 204 and turbine 206 is downstream of the fan 200. In sections has an even larger area at a downstream end of fact, as can be appreciated, the ellipses which form the inlet said inlet duct leading into a fan.

duct could be said to have a first set of ellipses as the lower 7. The blended wing aircraft as set forth in claim 6, wherein ellipses 142/242/342, and a second set of ellipses as the upper a center of the inlet duct cross-section is defined between said ellipses 144/244/344.

first and second sets of ellipse sections and, a distance By designing the inlet duct 40 according to the teachings between said center and said surface defining said second set above, the airflow will be more uniform by the time it reaches of ellipse sections increasing as one moves further into said the fan 200, and the effects of the boundary layer from the inlet duct and toward said fan.

fuselage 22 will be dramatically reduced.

8. The blended wing aircraft as set forth in claim 7, wherein FIG. 6 shows another duct embodiment 210. In duct a vertical semi-axis of the first set of ellipse sections is gen- embodiment 210, the lower or bottom surface 212 is formed erally constant from said upstream end to said downstream such that it has a generally constant vertical semi-axis, while end.

the upper or top surface 214 expands much like the lower 9. The blended wing aircraft as set forth in claim 8, wherein surface 32 of the FIG. 3B embodiment.

said first set of ellipse sections is in a vertically upper half of A worker of ordinary skill in this art would recognize when 60 said inlet duct.

either of the inlet shape options would be most efficient to 10. The blended wing aircraft as set forth in claim 8, utilize. Of course, other shapes may be utilized as well.

wherein said first set of ellipse sections is in a vertically lower Although an embodiment of this invention has been dis- half of said inlet duct.

closed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of thi s