US20070183890A1 - Leaned deswirl vanes behind a centrifugal compressor in a gas turbine engine - Google Patents

Abstract

A compressor includes a deswirl assembly to improve aerodynamic coupling with the combustor. The assembly includes an annular housing and a plurality of vanes. The annular housing includes an inner and an outer annular wall disposed concentric to each other, and a flowpath defined therebetween. The plurality of vanes is disposed in the flowpath in a substantially annular pattern. Each vane has a leading edge, a trailing edge, a convex surface, and concave surface, and each of the convex and concave surfaces extends between the leading and trailing edges. Additionally, each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall. The vanes preferably have a uniform axial cross section for ease of manufacturing.

Description

TECHNICAL FIELD
• The present invention relates to a gas turbine engine and, more particularly, to a deswirl assembly having leaned deswirl vanes for use in the gas turbine engine.
BACKGROUND
• A gas turbine engine may be used to power various types of vehicles and systems. A typical gas turbine engine includes a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section induces air from the surrounding environment into the engine and accelerates a fraction of the air toward the compressor section. The compressor section compresses the pressure of the air to a relatively high level and directs the air to the combustor section. A steady stream of fuel is injected into the combustor section, and the injected fuel is ignited to significantly increase the energy of the compressed air. The high-energy compressed air then flows into and through the turbine section, causing rotationally mounted turbine blades therein to rotate and generate energy. The air exiting the turbine section is exhausted from the engine via the exhaust section, and the energy remaining in the exhaust air aids the thrust generated by the air flowing through a bypass plenum.
• In some engines, the compressor section is implemented with a centrifugal compressor. A centrifugal compressor typically includes at least one impeller that is rotationally mounted to a rotor and surrounded by a shroud. When the impeller rotates, it compresses and imparts tangential velocity to the air received from the fan section and the shroud directs the air radially outward into a diffuser. The diffuser decreases the radial and tangential velocity of the air and increases the static pressure of the air and directs the air into a deswirl assembly. The deswirl assembly includes an annular housing having a plurality of straight radially extending vanes mounted therein that straighten and reduce the tangential velocity component of the air flow before it enters the combustor section. The combustor section in some engines is implemented with an axial through flow combustor that includes an annular combustor disposed within a combustor housing that defines a plenum. The straightened air enters the plenum and travels axially through the annular combustor where it is mixed with fuel and ignited.
• Recently, conventional deswirl assemblies have included downcanted outlets to improve aerodynamic coupling between the diffuser and combustor. However, it has been found that these deswirl assemblies generate greater flow angle variation across the span of the flowpath at the deswirl vane leading edge and therefore may not adequately condition air flow to a sufficiently low mach number in an acceptably efficient manner unless the overall axial length and/or radial envelope of the assembly is increased. Because engines are continually designed to be smaller, the size increase may not be acceptable in newer aircraft. As a result, the configuration of the deswirl assembly has had to be redesigned. One preferred configuration includes vanes that are shaped so that the vane can accept a large variation in air angle at its leading edge. The vanes may also be configured such that the pressure side of each vane faces radially inwardly. However, although this configuration optimizes airflow through the deswirl assembly, manufacture of the assembly is relatively time-consuming and costly because each vane may need to be individually formed and shaped.
• Hence, there is a need for an improved downcanted deswirl assembly that includes a plurality of vanes that are configured to aerodynamically couple a centrifugal compressor and an axial through-flow combustor. Additionally, it is desirable for the deswirl assembly to be relatively inexpensive and simple to manufacture. Moreover, it is desirable for the deswirl assembly to suitably direct and condition the air flowing there through for optimal engine performance.
BRIEF SUMMARY
• The present invention provides a deswirl assembly for receiving air flow from a diffuser. The deswirl assembly includes an annular housing and a plurality of vanes. The annular housing includes an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween. The plurality of vanes is disposed in the flowpath in a substantially annular pattern. Each vane has a leading edge, a trailing edge, a convex surface, and concave surface, and each of the convex and concave surfaces extends between the leading and trailing edges. Additionally, each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall.
• In one embodiment, and by way of example only, the deswirl assembly including an annular housing, and a first and a second plurality of vanes. The annular housing includes an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween. The first plurality of vanes is disposed in the flowpath in a substantially annular pattern, and each vane has a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extending between the leading and trailing edges, each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall and each vane has an axial cross section shape, and each axial cross section shape is substantially the same. The second plurality of vanes is disposed in the flowpath in a substantially annular pattern downstream of the first plurality of vanes. Each vane has a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extends between the leading and trailing edges, and each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall. Additionally, each vane of the second plurality of vanes has an axial cross section shape, and each axial cross section shape is substantially the same.
• In still another embodiment, a system is provided for aerodynamically coupling air flow from a centrifugal compressor to an axial combustor, where the compressor and combustor are disposed about a longitudinal axis. The system includes a diffuser, a deswirl assembly, combuster inner and outer annular liners, a combustor dome, and a curved annular plate. The diffuser has an inlet, an outlet and a flow path extending therebetween, where the diffuser inlet is in flow communication with the centrifugal compressor, and the diffuser flowpath extends radially outward from the longitudinal axis. The deswirl assembly includes an annular housing and a plurality of vanes. The annular housing includes an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween. The plurality of vanes is disposed in the flowpath in a substantially annular pattern. Each vane has a leading edge, a trailing edge, a convex surface, and concave surface, and each of the convex and concave surfaces extends between the leading and trailing edges. Additionally, each vane extends between and is angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall. The combustor inner annular liner is disposed about the longitudinal axis, and the inner annular liner has an upstream end. The combustor outer annular liner is disposed concentric to the combustor inner annular liner and forms a combustion plenum therebetween. The outer annular liner has an upstream end. The combustor dome is coupled to and extends between the combustor inner and outer annular liner upstream ends. The curved annular plate is coupled to the combustor inner and outer annular liner upstream ends to form a combustor subplenum therebetween, and the curved annular plate has a first opening and a second opening formed therein. The first opening is aligned with the deswirl assembly outlet to receive air discharged therefrom.
• Other independent features and advantages of the preferred deswirl assembly will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a simplified cross section side view of an exemplary multi-spool turbofan gas turbine jet engine according to an embodiment of the present invention;
• FIG. 2 is a cross section view of a portion of an exemplary combustor that may be used in the engine ofFIG. 1;
• FIG. 3 is a cutaway view of a portion of an exemplary deswirl assembly that may be implemented into the combustor shown inFIG. 2 forward looking aft;
• FIG. 4 is the portion of the exemplary deswirl assembly shown inFIG. 3 aft looking forward; and
• FIG. 5 is a top view of the exemplary deswirl assembly shown inFIG. 3.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
• Before proceeding with the detailed description, it is to be appreciated that the described embodiment is not limited to use in conjunction with a particular type of turbine engine. Thus, although the present embodiment is, for convenience of explanation, depicted and described as being implemented in a multi-spool turbofan gas turbine jet engine, it will be appreciated that it can be implemented in various other types of turbines, and in various other systems and environments.
• An exemplary embodiment of a multi-spool turbofan gasturbine jet engine100 is depicted inFIG. 1, and includes anintake section102, acompressor section104, acombustion section106, aturbine section108, and anexhaust section110. Theintake section102 includes afan112, which is mounted in afan case114. Thefan112 draws air into theintake section102 and accelerates it. A fraction of the accelerated air exhausted from thefan112 is directed through abypass section116 disposed between thefan case114 and anengine cowl118, and provides a forward thrust. The remaining fraction of air exhausted from thefan112 is directed into thecompressor section104.
• Thecompressor section104 includes two compressors, anintermediate pressure compressor120, and ahigh pressure compressor122. Theintermediate pressure compressor120 raises the pressure of the air directed into it from thefan112, and directs the compressed air into thehigh pressure compressor122. Thehigh pressure compressor122 compresses the air still further, and directs the high pressure air into thecombustion section106. In thecombustion section106, which includes anannular combustor124, the high pressure air is mixed with fuel and combusted. The combusted air is then directed into theturbine section108.
• Theturbine section108 includes three turbines disposed in axial flow series, ahigh pressure turbine126, anintermediate pressure turbine128, and alow pressure turbine130. The combusted air from thecombustion section106 expands through each turbine, causing it to rotate. The air is then exhausted through apropulsion nozzle132 disposed in theexhaust section110, providing additional forward thrust. As the turbines rotate, each drives equipment in theengine100 via concentrically disposed shafts or spools. Specifically, thehigh pressure turbine126 drives thehigh pressure compressor122 via ahigh pressure spool134, theintermediate pressure turbine128 drives theintermediate pressure compressor120 via anintermediate pressure spool136, and thelow pressure turbine130 drives thefan112 via alow pressure spool138.
• Turning now toFIG. 2, an exemplary cross section of the area between thehigh pressure compressor122 andannular combustor124 is illustrated. In addition to thecompressor122 andcombustor124,FIG. 2 depicts adiffuser204 and adeswirl assembly206, each disposed about alongitudinal axis207. Thehigh pressure compressor122 is preferably a centrifugal compressor and includes animpeller208 and ashroud210 disposed in acompressor housing211. Theimpeller208, as alluded to above, is driven by thehigh pressure turbine126 and rotates about thelongitudinal axis207. Theshroud210 is disposed around theimpeller208 and defines an impellerdischarge flow passage212 therewith that extends radially outwardly.
• Thediffuser204 is coupled to theshroud210 and is configured to decrease the velocity and increase the static pressure of air that is received therefrom. In this regard, any one of numerousconventional diffusers204 suitable for operating with a centrifugal compressor may be employed. In any case, thediffuser204 includes aninlet214, anoutlet216, and aflow path218 that each communicates with thepassage212, and theflow path218 is configured to direct the received air flow radially outwardly.
• Thedeswirl assembly206 communicates with thediffuser204 and is configured to substantially remove swirl from air received therefrom, to thereby decrease the Mach number of the air flow. Thedeswirl assembly206 includes an innerannular wall220, an outerannular wall222, and two pluralities ofvanes224,226 disposed therebetween. Thewalls220,222 define aflow path228 that is configured to redirect the air from its radially outward direction to a radially inward and axially downstream direction. In this regard, thewalls220,222 are formed such that theflow path228 extends between aninlet230 andoutlet232 in anarc233 so that when the air exits theoutlet232, it is directed at an angle and toward thelongitudinal axis207 and theannular combustor124. As the angle of thearc233 is increased the variation of the air angle between theinner wall220 and outwall222 is increased.
• As briefly mentioned above, the two pluralities ofvanes224,226 are disposed between thewalls220,222. To secure thevanes224,226 to theassembly206, eachwall220,222 includes two sets ofslots234,236,238,240 that are formed in annular patterns along two axial positions. Preferably, theslots234,236,238,240 are formed downstream of thearc233. Each of thevanes224,226 includes at least a top242,244 and a bottom246,248 that extend through theslots234,236,238,240. Thevanes226,228 may be secured to thewalls220,222 in any one of numerous fashions, such as, for example, by brazing.
• To condition the airflow to a sufficiently low Mach number, each vane preferably has a substantially identical predetermined shape and is positioned in theflow path228 at a predetermined angle relative to thewalls220,222.Exemplary vanes300, which are shown as being implemented into the two pluralities ofvanes224,226, are depicted inFIGS. 3 and 4. As briefly mentioned above,FIG. 3 is a cutaway view of the deswirl assembly200 looking at thevanes300 from forward to aft, whileFIG. 4 is the deswirl assembly shown inFIG. 3 looking at thevanes300 from aft to forward.
• Eachvane300 includes aleading edge302 and a trailingedge304. Aconcave pressure surface306 and aconvex suction surface308 extend between the leading and trailingedges302,304. Thevanes300 preferably each have a uniformly shaped curved axial cross-section from top310 tobottom312. In this regard, a number of thevanes300 having substantially identical shapes may be mass produced from a single sheet of material. Specifically, the sheet of material may be suitably pressed into an appropriate curve shape to form the concave andconvex surfaces306,308 and a plurality of thevanes300 may be cut from the single sheet of material.
• As mentioned previously, eachvane300 of the two pluralities ofvanes224,226 is disposed at an angle relative to thewalls220,222. Preferably, thevanes300 are each placed such that theconcave pressure surface306 faces outwardly toward the outerannular wall222 and theconvex suction surface308 faces inwardly toward the innerannular wall220. Angling thevanes300 in this preferred embodiment reduces the variation in air angle between thewalls220,222. In one exemplary embodiment, thevanes300 are disposed such that an angle between theconcave pressure surface208 the innerannular wall220 is about 110.8°. However, it will be appreciated that the particular angle at which thevanes224,226 are disposed depends on the overall configuration of thewalls220,222.
• The degree to which thevanes224,226 are angled may also determine how the two pluralities ofvanes224,226 are placed relative to each another. In one example, as shown inFIGS. 3 and 4, the vanes of the first plurality ofvanes224 are equally spaced apart from one another and the trailing edge of each vane is disposed around a firstcircumferential position242 around the innerannular wall220, while the vanes of the second plurality ofvanes226 are also equally spaced apart from one another but the leading edge of each is disposed around a secondcircumferential position244. Although the first and secondcircumferential positions242,244 are shown in this embodiment as non-overlapping and the firstcircumferential position242 is disposed upstream of the secondcircumferential position244, the firstcircumferential position242 may alternatively be disposed downstream of the secondcircumferential position244, or may overlap.
• Additionally, the second plurality ofvanes226 are preferably staggered between the first plurality ofvanes224. For instance, as shown inFIG. 5 viewing thevanes300 from forward250 to aft252, onevane226bof the second plurality ofvanes226 is preferably disposed between twovanes224a,224bof the first plurality ofvanes224 and biased toward thepressure surface306 of vane224b. In one exemplary embodiment, adistance254 betweenvane226bof the second plurality ofvanes226 and vane224bof the first plurality ofvanes224 is about 35% of thedistance256 betweenvanes224a,224bof the first plurality ofvanes224. It will be appreciated, however, that the particular distances between all of the vanes may largely depend on the angling thereof relative to thewalls220,222.
• It will further be appreciated that although two pluralities ofvanes226,228 are included in the embodiment shown inFIG. 2, the deswirl assembly200 may alternatively only include a single plurality of vanes. In still other embodiments, more than two pluralities ofvanes226,228 may need to be employed.
• An improved downcanted deswirl assembly has now been provided that includes a plurality of vanes that are configured to aerodynamically couple a centrifugal compressor and an axial through-flow combustor. Additionally, the deswirl assembly is relatively inexpensive and simple to manufacture and is capable of directing and conditioning the air flowing there through for optimal engine performance
• While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (20)

1. A deswirl assembly for receiving air flow from a diffuser, the deswirl assembly comprising:

an annular housing including an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween; and

a plurality of vanes disposed in the flowpath in a substantially annular pattern, each vane having a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extending between the leading and trailing edges, each vane extending between and angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall.

2. The deswirl assembly ofclaim 1, wherein each vane has an axial cross section shape, and each axial cross section shape is substantially the same.

3. The deswirl assembly ofclaim 1, further comprising a second plurality of vanes disposed in the flowpath in a substantially annular pattern downstream of the first plurality of vanes.

4. The deswirl assembly ofclaim 1, wherein the trailing edges of the vanes of the first plurality of vanes are disposed around a first circumferential position around the inner annular wall and the leading edges of the vanes of the second plurality of vanes are disposed around a second circumferential position around the inner annular wall.

5. The deswirl assembly ofclaim 4, wherein the first and second circumferential positions do not overlap.

6. The deswirl assembly ofclaim 4, wherein the first circumferential position is disposed downstream of the first circumferential position.

7. The deswirl assembly ofclaim 4, wherein the vanes of the second plurality of vanes are each staggered between vanes of the first plurality of vanes.

8. The deswirl assembly ofclaim 7, wherein at least one vane of the first plurality of vanes is disposed between two vanes of the second plurality of vanes and a first distance between the at least one vane of the first plurality of vanes and one of the two vanes of the second plurality of vanes is less than a second distance between the two vanes of the second plurality of vanes.

9. The deswirl assembly ofclaim 8, wherein the first distance is about 35% of the second distance.

10. A deswirl assembly for receiving air flow from a diffuser, the deswirl assembly comprising:

an annular housing including an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween;

a first plurality of vanes disposed in the flowpath in a substantially annular pattern, each vane having a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extending between the leading and trailing edges, each vane extending between and angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall and each vane has an axial cross section shape, each axial cross section shape being substantially the same; and

a second plurality of vanes disposed in the flowpath in a substantially annular pattern downstream of the first plurality of vanes, each vane having a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extending between the leading and trailing edges, each vane extending between and angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall and each vane has an axial cross section shape, each axial cross section shape being substantially the same.

11. The deswirl assembly ofclaim 10, wherein the trailing edges of the vanes of the first plurality of vanes are disposed around a first circumferential position around the inner annular wall and the leading edges of the vanes of the second plurality of vanes are disposed around a second circumferential position around the inner annular wall.

12. The deswirl assembly ofclaim 11, wherein the first and second circumferential positions do not overlap.

13. The deswirl assembly ofclaim 11, wherein the first circumferential position is disposed downstream of the first circumferential position.

14. The deswirl assembly ofclaim 11, wherein the vanes of the second plurality of vanes are each staggered between vanes of the first plurality of vanes.

15. The deswirl assembly ofclaim 14, wherein at least one vane of the first plurality of vanes is disposed between two vanes of the second plurality of vanes and a first distance between the at least one vane of the first plurality of vanes and one of the two vanes of the second plurality of vanes is less than a second distance between the two vanes of the second plurality of vanes.

16. The deswirl assembly ofclaim 15, wherein the first distance is about 35% of the second distance.

17. A system for aerodynamically coupling air flow from a centrifugal compressor to an axial combustor, the compressor and combustor disposed about a longitudinal axis, the system comprising:

a diffuser having an inlet, an outlet and a flow path extending therebetween, the diffuser inlet in flow communication with the centrifugal compressor, and the diffuser flow path extending radially outward from the longitudinal axis;

a deswirl assembly coupled to the diffuser and comprising:

an annular housing including an inner annular wall, an outer annular wall disposed concentric to the inner annular wall, and a flowpath defined therebetween, the flow path in flow communication with the diffuser outlet to receive air flowing in a radially outward direction, and the deswirl assembly flow path configured to redirect the air in a radially inward and axial direction through the deswirl assembly outlet at an angle toward the longitudinal axis; and

a plurality of vanes disposed in the flowpath in a substantially annular pattern, each vane having a leading edge, a trailing edge, a convex surface, and concave surface, each of the convex and concave surfaces extending between the leading and trailing edges, each vane extending between and angled relative to the inner and the outer annular walls such that the concave surface faces the outer annular wall and the convex surface faces the inner annular wall;

a combustor inner annular liner disposed about the longitudinal axis, the inner annular liner having an upstream end;

a combustor outer annular liner disposed concentric to the combustor inner annular liner and forming a combustion plenum therebetween, the outer annular liner having an upstream end;

a combustor dome coupled to and extending between the combustor inner and outer annular liner upstream ends; and

a curved annular plate coupled to the combustor inner and outer annular liner upstream ends to form a combustor subplenum therebetween, the curved annular plate having a first opening and a second opening formed therein, the first opening aligned with the deswirl assembly outlet to receive air discharged therefrom.

18. The deswirl assembly ofclaim 17, wherein each vane has an axial cross section shape, and each axial cross section shape is substantially the same.

19. The deswirl assembly ofclaim 17, further comprising a second plurality of vanes disposed in the flowpath in a substantially annular pattern downstream of the first plurality of vanes.

20. The deswirl assembly ofclaim 17, wherein:

the vanes of the second plurality of vanes are each staggered between vanes of the first plurality of vanes;

at least one vane of the first plurality of vanes is disposed between two vanes of the second plurality of vanes and a first distance between the at least one vane of the first plurality of vanes and one of the two vanes of the second plurality of vanes is less than a second distance between the two vanes of the second plurality of vanes; and

the first distance is about 35% of the second distance.

Images