CA2652708A1

CA2652708A1 - Flow-control technique to vector bulk flow leaving a vane

Info

Publication number: CA2652708A1
Application number: CA002652708A
Authority: CA
Inventors: David R. Williams
Original assignee: Honeywell International Inc
Current assignee: ACHARYA MUKUND; Honeywell International Inc
Priority date: 2006-05-18
Filing date: 2007-05-18
Publication date: 2008-05-15
Also published as: WO2008057627A3; EP2019924A2; WO2008057627A2

Abstract

A guide vane assembly including an annular casing and vanes that are coupled to and extend radially inwardly from the annular casing. Each vane includes a first wall, a second wall, a leading edge, a first wall trailing edge, and a second wall trailing edge. The first and second walls are coupled at the leading edge and spaced apart to define a plenum therebetween. The trailing edges are spaced apart to define a gap therebetween. The first wall trailing edge includes a lip extending therefrom toward the second wall, and the second wall trailing edge includes a bulb section extending along at least a portion of a length thereof. The second wall trailing edge is disposed at least partially inside the lip, wherein a substantial entirety of the vane between an outer surface of the second wall and an outer surface of the bulb portion is rounded.

Description

FLOW-CONTROL TECHNIQUE TO VECTOR BULK FLOW LEAVING A VANE

CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No.
60/801,338, filed May 18, 2006.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT

[0002] This invention was made with Government support under DAAD19-00-C-0125 awarded by the Department of Defense. The Government has certain rights in this invention.

TECHNICAL FIELD

[0003] The present invention relates to a gas turbine engine and, more particularly, to vanes for use in a fan section or a compressor section of the engine.
BACKGROUND

[0004] Turbofan gas turbine engines typically include five major sections, for example, a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section is positioned at the front, or "inlet"
section of the engine, and includes a fan that induces air from the surrounding environment into the engine, and accelerates a fraction of this air toward the compressor section. The remaining fraction of air induced into the fan section is accelerated into and through a bypass plenum, and out the exhaust section.

[0005] The compressor section, which may include one or more compressors, raises the pressure of the air it receives from the fan section to a relatively high level.
The compressed air then enters the combustor section, where a ring of fuel nozzles injects a steady stream of fuel. The injected fuel is ignited by a burner, significantly increasing the energy of the resulting hot, compressed gases, and the gases then flow into and through the turbine section to cause rotationally mounted turbine blades to rotate and generate energy. The gases exiting the turbine section are exhausted from the engine via the exhaust section, and the energy remaining in this exhaust stream aids the thrust generated by the air flowing through the bypass plenum.

[0006] To direct the flow of air out of the fan section or to direct the flow of air within the compressor, a guide vane assembly is typically disposed therein.
The guide vane assembly includes variable geometry guide vanes that typically extend radially inward from the annular casing towards a hub. In many cases, the guide vanes are coupled to a plurality of actuators via unison rings, linkages, and bell-cranks, that, when moved, changes the positioning of the guide vanes to thereby control the direction and amount of airflow into downstream sections of the engine.

[0007] Although the above-described assembly adequately controls airflow, it suffers from certain drawbacks. For example, typically the guide vanes are fixed in a single position during aircraft operation or scheduled to be set at pre-determined positions based on engine speed; thus, they may not adequately respond to a rapid airflow change in the event a distortion is present in the compressor.
Additionally, the engine may not operate as efficiently with the fixed guide vanes. Moreover, the guide vane assembly includes many components which may undesirably add weight and/or cost to an aircraft.

[0008] Hence, there is a need for a guide vane assembly that includes guide vanes that respond to rapid changes in airflow. Additionally, there is a need for a guide vane assembly that has few components and that is relatively inexpensive to implement. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

BRIEF SUMMARY

[0009] The present invention provides a guide vane assembly. In one embodiment, and by way of example only, the inlet guide vane assembly includes an annular casing, and a plurality of vanes. The plurality of vanes is coupled to and extends radially inwardly from the annular casing. Each vane includes a first wall, a second wall, a leading edge, a first wall trailing edge, and a second wall trailing edge.
The first and second walls are coupled at the leading edge and spaced apart to define a plenum therebetween. The first and second wall trailing edges are spaced apart to define a gap therebetween. The first wall trailing edge includes a lip extending therefrom toward the second wall, and the second wall trailing edge includes a bulb section extending along at least a portion of a length thereof. The second wall trailing edge is disposed at least partially inside the lip, wherein a substantial entirety of the vane between an outer surface of the second wall and an outer surface of the bulb portion is rounded.

[0010] In another embodiment, and by way of example only, the guide vane assembly includes an annular casing and a plurality of vanes. The annular casing includes a manifold and a plurality of openings in communication with the manifold.
The plurality of vanes is coupled to and extends radially inwardly from the casing, and each vane includes a first wall, a second wall, a leading edge, a first wall trailing edge, a second wall trailing edge, and a stem. The first and second walls are coupled at the leading edge and spaced apart to define a plenum therebetween. The first and second wall trailing edges are spaced apart to define a gap therebetween. The first wall trailing edge includes a lip extending therefrom toward the second wall, and the second wall trailing edge includes a bulb section extending along at least a portion of a length thereof The second wall trailing edge is disposed at least partially inside the lip, wherein a substantial entirety of the vane between an outer surface of the second wall and an outer surface of the bulb portion is rounded. The stem is configured to be disposed in a corresponding opening of the manifold plurality of openings, and includes an aperture providing communication between the manifold and the plenum.

[0011] In still another embodiment, the guide vane assembly includes an annular casing, a plurality of vanes, and an air source. The annular casing includes a manifold and a plurality of openings in communication with the manifold. The plurality of vanes is coupled to and extend radially inwardly from the annular casing and defines at least one flow passage therebetween. Each vane includes a first wall, a second wall, a leading edge, a first wall trailing edge, a second wall trailing edge, and a stem.
The first and second walls are coupled at the leading edge and spaced apart to define a plenum therebetween. The first and second wall trailing edges are spaced apart to define a gap therebetween. The first wall trailing edge includes a lip extending therefrom toward the second wall, and the second wall trailing edge includes a bulb section extending along at least a portion of a length thereof. The second wall trailing edge is disposed at least partially inside the lip, wherein a substantial entirety of the vane between an outer surface of the second wall and an outer surface of the bulb portion is rounded. The stem is configured to be disposed in a corresponding opening of the manifold plurality of openings, and includes an aperture providing communication between the manifold and the plenum. The air source is in flow communication with the annular casing plenum and is configured to selectively supply air thereto to thereby provide air to the vane plenum and vane gap such that when air flows through the flow passage in a first direction, air flowing through the vane gap redirects the flow passage air to flow in a second direction.

[0012] Other independent features and advantages of the preferred vane 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

[0013] FIG. 1 is a cross section view of an exemplary gas turbine engine;

[0014] FIG. 2 is a cutaway view of an exemplary inlet guide vane assembly that may be implemented into the fan module of FIG. 1;

[0015] FIG. 3 is an isometric view of an exemplary vane that may be implemented into the inlet guide vane assembly shown in FIG. 2;

[0016] FIG. 4 is a cutaway view of the vane shown in FIG. 3;

[0017] FIG. 5 is a cross section view of the vane shown in FIG. 3; and [0018] FIG. 6 is a close up view of a trailing section of the exemplary vane of FIG. 5.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0019] The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Specifically, although the figures and description describe an inlet guide vane assembly of a fan module, the invention may be implemented into other sections of an engine, such as in a compressor guide vane assembly. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.

[0020] Turning now to the description and with reference first to FIG. 1, a partial cross section side view of a turbofan jet engine 100 is depicted. The turbofan jet engine 100 includes a fan module 110, a compressor module 120, a combustor and turbine module 130 and an exhaust module 140. The fan module 110 is positioned at the front, or "inlet" section of the engine 100, and includes an inlet guide vane assembly 106 that directs a primary airflow 202 (shown in FIG. 2) into the fan module 110. The fan module 110 also includes a fan 108 that induces air from the surrounding environment into the engine 100. The fan module 110 accelerates a fraction of this air as the primary airflow 202 toward the compressor module 120, and the remaining fraction is accelerated into and through a bypass 112, and out the exhaust module 140.

[0021] The compressor module 120 raises the pressure of the air it receives to a relatively high level. The compressor module 120 includes a low pressure section 150 and a high pressure section 160 through which the primary airflow 202 (shown in FIG. 2) travels. The low pressure section 150 typically includes stages, each of which includes rotors 170 and guide vane assemblies 175. Each of the rotors 170 has a plurality of blades (not shown) and is rotationally mounted on a low pressure shaft 190, which is driven by the low pressure turbine 116. As the rotors 170 rotate, the blades force primary airflow 202 through each of the guide vane assemblies 175 in subsequent sections. Each guide vane assembly 175 also includes a plurality of vanes.

[0022] The high-pressure compressed air then enters the combustor and turbine module 130, where a ring of fuel nozzles 114 (only one illustrated) injects a steady stream of fuel. The injected fuel is ignited by a burner (not shown), which significantly increases the energy of the resulting high-pressure compressed gases.
The high-energy compressed gases then flow first into a high pressure turbine 115 and then a low pressure turbine 116, causing rotationally mounted turbine blades 118 on each turbine 115, 116 to turn and generate energy. The energy generated in the turbines 115, 116 is used to power other portions of the engine 100, such as the fan module 110 and the compressor module 120. The gases exiting the combustor and turbine module 130 then leave the engine 100 via the exhaust module 140. The energy remaining in the exhaust stream aids the thrust generated by the air flowing through the bypass 112.

[0023] Turning now to FIG. 2, a cutaway view of an exemplary inlet guide vane assembly 200 is shown. The inlet guide vane assembly 200 may be used in the fan module 110 as inlet guide vane assembly 106 or in the compressor module 120 for guide vane assembly 175. In any case, the inlet guide vane assembly 200 is configured to direct a primary airflow 202 through a flow passage in a desired direction. In this regard, the guide vane assembly 200 includes an annular casing 204 and, as briefly mentioned above, a plurality of vanes 206. The annular casing 204 has a manifold 208 and a plurality of openings 210 (one of which is shown) formed therein, and both are in flow communication with a non-illustrated secondary air flow source. The openings 210, which fluidly communicate with the manifold 208, are configured to suitably receive the vanes 206.

[0024] Each vane 206, as shown in detail in FIGs. 3 and 4, includes an airfoi1304, a platform 306, and a stem 308. The platform 306 is configured to radially contain engine airflow and position the vane 206 in the primary flow path 202. The stem 308 attaches the vane 206 to the annular casing 204 and includes one or more apertures 310 formed therein that communicate with the annular casing manifold 208.
Although the stem 308 is shown with a cylinder 312 configuration machined therein, it will be appreciated that in other embodiments, any one of numerous other shapes suitable for attaching the vane 206 to the annular casing 204. Referring now to FIGs.
3-6, the airfoi1304 has two walls 314, 316, a leading edge 320, and a trailing section 324. The walls 314, 316 are spaced apart from one another to define a plenum therebetween and are joined together at the leading edge 320. The plenum 318 is configured to direct a secondary airflow 212 received from the stem aperture therethrough. In some embodiments, standoffs 322 may be disposed in the plenum 318 to direct the secondary airflow 212 in a desired direction. The standoffs extend between the two walls 314, 316 and may have any shape that affects the secondary airflow 212 in a desired manner.

[0025] Preferably, the walls 314, 316 and leading edge 320 are substantially smooth so that the primary airflow 202 traveling from the leading edge 320 toward the trailing section 324 flows substantially along the outer surface of the walls 314, 316. In cases in which a change in primary airflow direction is desired, as alluded to above, the secondary air source provides secondary air to the annular casing plenum 208, which travels through the vane plenum 318, and exits the trailing section 324.

[0026] The secondary airflow exits the vane plenum 318 through a gap 328 formed in the trailing section 324. With reference now to FIG. 6, a close up view of the trailing section 324 is provided. The gap 328 is defined by trailing edges 330, 332 that are formed on each of the walls 314, 316. To ensure that the secondary airflow 212 suitably carries a desired portion of the primary airflow 202 therewith, the trailing edge 330 of the first wa11314 preferably extends past the trailing edge 332 of the second wa11316. Additionally, the first wall trailing edge 330 includes a lip 334 that extends along substantially an entire length thereof and projects toward the second wa11316. The lip 334 may have a blunt edge, as shown in FIGs. 5 and 6, or alternatively, may have a sharp edge. The second wall trailing edge 332 includes a bulb portion 336 that extends the length thereof The bulb portion 336 is disposed inside of and is at least partially surrounded by the lip 334. To further ensure that the secondary airflow 212 affects the primary airflow 202 in a desired manner, a substantial entirety of the vane 206 between an outer surface of the second wa11316 and an outer surface of the bulb portion 336 is rounded. In another exemplary embodiment, a substantial entirety of the vane 206 between an inner surface of the second wa11316 and inner surface of the bulb portion 336 may also be smooth.

[0027] During operation, the primary airflow 202 flows along the outer surfaces of the first and second walls 314, 316. Because of the features of the trailing edge section as described above, the primary airflow 202 "stays attached" to the outer surfaces walls 314, 316. When a portion of the primary airflow 202 flows across the gap 328 in the trailing section 324 of the vane 206, the secondary airflow 212 interacts with the primary airflow 202. Consequently, the direction in which the primary airflow 202 travels is altered from a first direction to a second direction. The amount of directional change may be modified by adjusting the amount of air supplied by the secondary air supply source to the secondary airflow 212.
Thus, if a small amount of air is provided, the secondary airflow 212 will cause a slight change in primary airflow 202 direction. If a larger amount of air is supplied, the change in the primary airflow 202 direction will be more affected.

[0028] There has now been provided a guide vane assembly that is relatively inexpensive and lightweight to implement. The guide vane assembly may be retrofitted into currently existing gas turbine engines, or implemented in the design of new gas turbine engines. Additionally, the guide vane assembly redirects primary airflow by using a secondary airflow to interact therewith. Specifically, the secondary airflow remains attached to the rounded surface of the bulb portion of the trailing edge by a Coanda effect, changing the flow separation point and lift force acting on each vane. The change in lift force redirects the primary airflow by adding a swirl component transverse thereto.

[0029] 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

1. A guide vane assembly (200) for use in an engine, comprising:
an annular casing (204); and a plurality of vanes (206) coupled to and extending radially inwardly from the annular casing (204), each vane (206) including a first wall (314), a second wall (316), a leading edge (320), a first wall trailing edge (330), and a second wall trailing edge (332), the first and second walls (314, 316) coupled at the leading edge (320) and spaced apart to define a plenum (318) therebetween, the first and second wall trailing edges (330, 332) spaced apart to define a gap (328) therebetween, the first wall trailing edge (330) including a lip (334) extending therefrom toward the second wall (316), and the second wall trailing edge (332) including a bulb portion (336) extending along at least a portion of a length thereof, the second wall trailing edge (332) disposed at least partially inside the lip (334), wherein a substantial entirety of the vane between an outer surface of the second wall (316) and an outer surface of the bulb portion (336) is rounded.

2. The assembly of claim 1, wherein:
the annular casing (204) includes a manifold (208) and a plurality of openings (210) in communication with the manifold (208); and each vane (206) includes a stem (308) configured to be disposed in a corresponding opening of the plurality of openings (210), the stem (308) including an aperture (310) providing communication between the annular casing manifold (208) and the plenum (318).

3. The assembly of claim 2, further comprising an air source in flow communication with and configured to supply air to the annular casing manifold (208).

4. The assembly of claim 1, wherein the first wall (314) and the second wall (316) each has an inner surface and a standoff extends therebetween.

5. The assembly of claim 1, wherein the second wall (316) has an inner surface and the bulb portion (336) has an inner surface and a substantial entirety of the vane between the second wall inner surface and the bulb portion inner surface is smooth.

6. The assembly of claim 1, wherein the first wall trailing edge lip (334) has an end and at least a portion of the end is blunt.

7. The assembly of claim 1, wherein the first wall trailing edge lip (334) has an end and at least a portion of the end is sharp.