GB2085147A

GB2085147A - Flow modifying device

Info

Publication number: GB2085147A
Application number: GB8126831A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1980-10-01
Filing date: 1981-09-04
Publication date: 1982-04-21
Also published as: IT8124230A0; FR2491139A1; JPS5787536A; DE3138615A1

Abstract

A flow modifying device, such as that employed as a swirler on a combustion chamber of a gas turbine engine, which varies the amount and direction of discharge of fluid from the device. The device comprises a fixed member 30 having a curved inner surface and at least one radially facing aperture 31 therethrough, and a positionable member 40 radially adjacent the fixed member and having at least one slot 41 therethrough communicable with the aperture. Adjustment of the positionable member results in variation of the amount and direction of discharge of the fluid. <IMAGE>

Description

SPECIFICATION Flow modifying device This invention relates to flow modifying devices and particularly to a new and improved fluid flow modifying device in which the amount and direction of fluid discharge from the device can be varied.

One example of a method offuel-air ratio variation in a swirler of a gas turbine engine combustion chamber is the use of a shutter assembly for opening and closing air scoops. Most such assemblies, however, do not provide for swirl angle variation. Furthermore, scoop openings are often disposed normal to the flow of compressed air from the compressor and are thus subject to the stresses exerted by the compressed air. The shutter assembly must be built to withstand such stresses, a requirement which can, in turn, increase cost and weight.

The present invention comprises a flow modifying device which varies the amount and direction of fluid discharge from the device. The device is of the type arranged to receive fluid generally radially and discharge fluid generally axially. It comprises a fixed member, including a curved radially inner surface and at least one radially facing aperture therethrough, and a positionable member, disposed radially adjacent and outward of the fixed member and having at least one slot therethrough communicable with the aperture of the fixed member, the aperture and slot being effective at different relative positions to vary the amount and direction ofthe discharge flow of fluid passing through them. The device also includes means for adjusting the positionable member relative to the fixed member.

In one embodiment of the device, the fixed member includes a plurality of radially facing apertures therethrough and flanges extending inwardly from the upstream and downstream edges, and the positionable member includes a plurality of slots and generally tangentially extending lips for channeling fluid through the slots.

Another embodiment of the device is similar to the device is similar to the first embodiment, except that the generally tangentially extending lips comprise part of the fixed member, and the positionable member can include curved protrusions to aid in channeling fluid through the slot.

Athird embodiment of the device is also similar to the second embodiment except that it includes a second set of fixed and positionable members, referred to as a stationary member and a movable member. This embodiment permits variation in the amount and swirl angle ofthe air which initially mixes with fuel as the fuel enters a combustion chamber as well as permitting variation in the amount and swirl angle of air which subsequently mixes with that fuel-air mixture.

The means for adjusting the positionable member can comprise a drive arm conneced to the positionable member.

Figure lisa fragmentary cross-sectional view of a combustion chamber and a swirler incorporating features of the present invention.

Figures 2 through 4 are cross-sectional views of the swirler of Figure 1 taken along line 2-2 of Figure 1 and showing different relative positions of the fixed member and the positionable member.

Figure 5 is a fragmentary cross-sectional view of another embodiment of the swirler.

Figure 6 is a cross-sectional view of the swirler of Figure 5 taken along lines 6-6 of Figure 5.

Figure 7 is a fragmentary cross-sectional view of a third embodiment of the swirler.

Figure 8 is a fragmentary cross-sectiona view of the swirler of Figure 7 taken along lines 8-8 of Figure 7.

Turning now to a consideration of the drawing, and in particular to Figure 1, there is shown the upstream portion of a combustion chamber 20 in a gas turbine engine. A mixture of air and fuel enters and is burned within the combustion chamber 20.

The energy of the resulting exhaust gases is extracted to perform work, such as to rotate a turbine (not shown).

The fuel for combustion is introduced from fuel injecting means, such as the pressurized fuel nozzle 21. As the fuel exits the fuel nozzle 21, it is initially mixed with air within the swirler 22 and the resulting mixture enters the combustion chamber 20 to be mixed with additional air exiting the swirler and then to be burned. The swirler 22 imparts a swirling motion to the fuel emitted from the fuel nozzle 21 causing atomization of the fuel, thereby promoting better mixing.

The present invention comprises a flow modifying device, such as the swirler 22, which receives at least a portion of its fluid from a generally radial direction and discharges that fluid in a generally axial direction and which can vary the amount and direction of the discharge of the fluid, such as air, flowing through it. By "radial" it is meant in a direction generally perpendicular to the swirler longitudinal axis, depicted by the dashed line 23. By "axial" it is meant in a direction generally parallel to the swirler longitudinal axis 23. As will be seen, the fluid flowing in eitherthe radial or axial direction can include a rotational, or swirl, component imparted to it by the swirler 22.

The flow modifying device comprises a fixed member, a positionable member, and means for adjusting the positionable member. Figure 1 shows a particular embodiment ofthe flow modifying device. The fixed member 30 includes a generally curved, preferably cylindrically shaped, radially inner surface. The radially outer surface of the fixed member 30 is also preferably cylindrically shaped.

The radially inner surface, and preferably the radially outer surface, of the fixed member 30 are axially aligned. That is, the longitudinal axis of the fixed member 30 running through the center of the fixed member is parallel or substantially parallel to the swirler longitudinal axis 23.

The fixed member 30 includes at least one, and preferably a plurality of radially facing holes or apertures 31 therethrough, as can best be seen in Figure 2. The apertures 31 permit a fluid, such as air, to enter the interior of the fixed member.

The fixed member 30 also includes axially directed discharge means. For example, and as can be seen in Figure 1, the discharge means can comprise a first annular flange 32 and a second annular flange 33, which are spaced axially apart and extend from the upstream and downstream edges respectively of the fixed member 30. The first and second annular flanges 32 and 33 define a fluid flowpath therebetween for fluid, such as air, flowing through the apertures 31 (shown in Figure 2). Preferably, the first and second annular flanges 32 and 33 have generally curved, L-shaped cross sections and extend radially inwardly and axially downstream from the fixed member 30. The downstream edge of the first annularflange 32 is disposed radially inward of a portion of the second annular flange 33.Thus, air flows in a generally radially inward direction through the apertures 31 and as it flows between the first and second annular flanges 32 and 33, it is turned by them to flow and be discharged from the swirler 22 in a generally axial direction. As will be seen shortly, the air flowing in a radial or an axial direction can include a swirling component. The radially inner surface of the first annular flange 32 also comprises a hub 34 of the swirler 22 through which fuel from the fuel nozzle 21 flows. The first annular flange 32 can include or have attached with it a radially aligned, annular disk 35, having a gap nearthe center thereof for receiving the fuel and also having ducts orventuris 36 therein spaced around the gap for receiving air from a generally axial direction.Although not shown, such ducts can be angled or can include vanes for imparting a swirling motion to the air entering the hub 34.

Thus, initial mixing of air and fuel occurs in the interior of the hub 34 as airfrom the venturis 36 mixes with the fuel from the fuel nozzle 21. This mixture then exits the hub 34 and is further mixed with swirling air as it is discharged from the flowpath between the first and second annular flanges 32 and 33 of the swirler 22. It is the amount and direction of discharge of the second source of air, that it, the air entering the swirler radially and flowing through the fixed member 30 and the positionable member 40, which this embodiment of the present invention can vary.

The positionable member 40 is adjustable, preferably rotatably, relative to the fixed member in order to vary the amount and direction of the discharge, or swirl angle, of air from the swirler 22. The positionable member 40 is disposed radially adjacent and preferably outward of the radially outer surface of the fixed member 30. The positionable member 40 includes at least one and preferably a plurality of slots 41 therethrough, as is seen in Figure 2. The slots 41 are communicable with the apertures 31 in the fixed member 30. The positionable member preferably includes generally cylindrically shaped, axially aligned, radially inner and radially outer surfaces. Each curved, solid portion ofthe positionable member 40 between the slots 41 is of sufficient arc length to cover an aperture 31 in the fixed member 30.The positionable member 40 also includes a plurality of lips 42 extending generally tangentially from the solid portion of the positionable member adjacent the slots 41. The lips 42 can each be planar or they can each have a slight radially inward or outward curvature. Each of the lips 42 is preferably of spch a length that it overlies and is spaced radially outward of one of the slots 41. This arrangement permits the lips 42 to channel air through the slots 41 and apertures 31 so as to cause the airto enterthe fixed member 30 in a generally tangential direction.

As the air enters the swirler 22 radially, it impinges against and flows along the curved outer surface of the positionable member 40, is turned by the lips 42 - to flow generally tangentially through the slots 41 and apertures 31, and then flows along the curved radially inner surface of the fixed member 30. Thus, a swirling motion is imparted to the air. As will be further described hereinafter, the direction of discharge of the air, that is, the swirl angle imparted, and the amount of air which is discharged from the swirler 22 is determined by the relative positions of the fixed member 30 and the positionable member 40.

As can be seen in Figure 1,the positionable member 40 preferably includes annular, radially extending end plates 43 and 44 which protrude outwardly from the upstream and downstream edges respectively of the positionable member. The end plates 43 and 44 channel the air radially into the swirler 22. The end plate 43 also protects the fixed member 30 and the positionable member 40 from the stresses which would otherwise be exerted by a direct flow of compressed air against them. The swirler 22 is thus a relatively simple and lightweight flow modifying device which is nevertheless capable of withstanding the stresses exerted upon it.

The swirler 22 is mounted at the upstream end of the combustion chamber 20 by any appropriate means. One example of such appropriate means is an annular bracket 37 which is shown in Figure 1 attached with the downstream portion of the second annular flange 33 and to the wall 38 of the combustion chamber 20.

Varying of the amount and direction of the discharge of air from the swirler 22 is accomplished by rotatably adjusting, or positioning, the positionable member 40 relative to the fixed member 30. As can be seen in Figure 1, the means for adjusting the positionable member 40 preferably comprises a drive arm 50, connected at its radially inner end to a portion of the positionable member 40, such as to the end plate 44. Movement of the drive arm 50 correspondingly adjusts the positionable member 40 relative to the fixed member 30. The radially outer portion of the drive arm 50 is connected with means which impart motion to the drive arm. For example, the drive arm 50 can be connected to a unison ring 51. The unison ring 51 can be connected with other drive arms associated with other swirlers in the engine combustion section such that the unison ring will move all of the drive arms in unison.

This embodiment of the flow modifying device operates as follows. Figure 2 shows the swirler 22 in its open position. The positionable member 40 has been adjusted to a position such that the slots 41 therein are aligned with the apertures 31 in the fixed member 30. Air for combustion enters from a generally radial direction between the end plates 43 and 44 and is channeled by the lips 42 through the slots 41 and apertures 31 to enter the fixed member 30 in a generally tangential direction. As the air flows along the curved inner surface of the fixed member 30, a swirl is imparted to it. The swirling air is then turned to flow in a generally axial direction by the first and second annular flanges 32 and 33. The air then exits the swirlerto mix with the fuel-air mixture exiting the hub 34 of the swirler 22. This mixture is burned in the combustion chamber 20.

Referring now to Figure 3, the positionable member40 has been rotatably adjusted to an intermediate position such that it partially covers the apertures 31 in the fixed member 30. Thus, the amount of air able to enter, and thus, be discharged from, the swirler 22 is reduced. Considering the effect upon swirl angle, since the pressure differential across the entire swirler 22 remains relatively constant, as the open area of the apertures 31 is reduced, the velocity of the air through the apertures increases. However, since the amount of air entering the swirler is reduced yet the exit area of the swirler between the first and second annular flanges 32 and 33 remains fixed, the exit velocity of The air is reduced.The next result of the intermediate position compared to the open position is that the air which does enter the swirler enters at a higher velocity and spends more tire e in the swirler, thus flowing for a greater distance along the curved inner surface of the fed member 30 before exiting. Therefore, the swirl angle of air is increased.

Referring now to Figure 4, the positionable member 48 has been rotatably adjusted to a closed position. The positionable member 40 covers the apertures 31 in the fixed member 30 such that sub stantially no air can pass through the apertures.

Thus, when the positionable member 40 is in the closed position, substantially he only air entering The combustion chamber 20 through The swirler 22 is Lhat entering generally axially from the venturis 36 through the hub 34, as can be seen in Figure 1. Of course, the positionable member 40 can be rotatably adjusted to numerous other positions between the open and closed position so as to permit numerous variations in the amount and direction of the discharge flow of air from the swirler 22.

Another embodiment of the flow modifying device is shown in Figures 5 and 6. The swirler 60 of this embodiment is similar to the swirler 22 of the first embodiment and the same numerals are used to indicate identical elements.

The swirler 60 comprises a fixed member, a positionable member, and means for adjusting the positionable member. Referring to Figures 5 and 6, the fixed member 61 includes a generally curved, preferably cylindricalls shaped, radially inner surface.

The radially outer surface of the fixed member 61 is also preferably cylindrically shaped. The radially inner surface, and preferably the radially outer surface of the fixed member 61, are axially aligned. That is, the longitudinal axis of the fixed member 61 running through the center of the fixed member is parallel to or substantially parallel to the swirler longitudinal axis 23. The fixed member 61 includes a plurality of radially facing apertures 62 therethrough and first and second annular flanges 32 and 33 extending from the upstream and down stream edges respec tively thernof. The first and second annular flanges 32 and 33 preferably have curved, L-shaped cross sections and extend generally radially inwardly and axially downstream from the fixed member 61.The fixed member 61 also includes a plurality of lips 63 which extend generally tangentially therefrom. Each of the lips 63 overlies and is spaced radially outward of one of the apertures 62. The lips 63 channel air through the aperture 62 so that the air enters the fixed member 61 in a generally tangential direction, thus imparting a swirling motion to the air. The first annular flange 32 can include or have attached with it a radially aligned, annular disk 35 having a gap near the center thereof for receiving fuel and also having ducts or venturis 36 therein spaced around the gap for receiving air from a generally axial direction.

Again referring to Figures 5 and 6, the positionable member 70 is preferably rotatably adjustable relative to the fixed member 61 and is disposed radially adjacent the radially outer surface of the fixed member 61. The positionable member 70 includes a plurality of slots 71 therethrough. The slots 71 are communicable with the apertures 62 in the fixed member 61.

The positionable member 70 preferably includes generally cylindrically shaped, axially aligned, radially inner and radially outer surfaces. Each solid portion of the positionable member 70 between the slots 71 is of sufficient arc length to cover an aper Sure 62 in the fixed member 61. The positionable member can include a plurality of curved protrusions 72 for guiding the airflow Through the slots 71 and apertures 62. The positionable member 70 includes annular, radially extending end plates 43 and 44 protruding outwardly from the upstream and downstream edges respectively of the positionable member. The end plates 43 and M. channel the air radially into the swirler 60.The end plate 43 protects the fixed member 61 and the positionable member 70 from the stresses which would otherwise be exerted by a direct flow of compressed air against them.

Means for adjusting the positionable member 70 is preferably the same as that used in the first embodiment. A drive arm 50 is connected at its radially inner end to the end plate 44. Movement ofthe drive arm 50 correspondingly adjusts the positionable member 70 relative to the fixed member 30.

The swirler 60 is mounted at the upstream end of the combustion chamber 20 in the same manner as was the swirler 22, as, for example, by an annular bracket 37.

This embodiment of the flow modifying device operates as follows. The solid lines of Figure 6 show the swirler 60 in its open position. The positionable member 70 is adjusted such that the slots 71 therein are aligned with the apertures 62 in the fixed member 61. Air for combustion enters from a generally radial direction between the end plates 43 and 44 and is channeled by the curved protrusions 72 and the lips 63 through the slots 71 and apertures 62 to enter the fixed member 61 in a generally tangential direction. As the air flows along the curved inner surface of the fixed member 61, a swirl is imparted to it. The swirling air is then turned to flow in a gener ally axial direction by the first and second annular flanges 32 and 33. The air then exits the swirler 60 and enters the combustion chamber 20.

The dashed line in Figure 6 shows the positionable member 70 after it has been rotatably adjusted to the closed position. In the closed position, the positionable member 70 covers the apertures 62 in the fixed member61,substantially preventing any airfrom passing through the apertures.

The positionable member 70 can be rotatably adjusted to numerous intermediate positions so as to vary the amount of air which will be discharged from the swirler 60. Also, the more the apertures 62 are covered by the positionable member 70, the greate will be the swirl angle of the air, forthe same reasons as were explained for the first embodiment.

Thus, rotatably adjusting the positionable member 70 relative to the fixed member 61 enables varying of the amount and direction of the discharge of airfrom the swirler 60. Such variation, in turn, improves combustor efficiency, reduces undesirable gaseous emissions, and improves fuel-air mixing and distribution of the mixture within the combustion chamber.

Athird embodiment of the invention is shown in Figures 7 and 8. The swirler 80 of this embodiment is similar to that of the second embodiment and the same numerals are used to indicate identical elements.

The swirler 80 includes a fixed member 61, such as that shown in Figure 6, having apertures there Through, generally tangentially extending lips adjacent the apertures, and first and second annular flanges 32 and 33 extending radially inward and downstream therefrom. The swirler 80 also includes a positionable member 70 having slots therethrough and curved protrusions 72 and end plates 43 and 44 extending radially therefrom. The above-described fixed member 61 and positionable member 70 are arranged and function the same in this embodiment as they did in the second embodiment. The swirler 80 of this embodiment, however, adds an additional fixed and positionable member to replace the venturi 36 of the second embodiment. These additional fixed and positionable members will be hereinafter referred to as a stationary member and a movable member, respectively, to avoid confusion.Such an arrangement permits variation in the amount and direction of discharge ofthe air entering the hub portion of the swirler which initially mixes with the fuel from the fuel nozzle 21.

The swirler 80 thus includes a stationary member 81 disposed upstream of the fixed member 61 and having generally curved, preferably cylindrically shaped, radially inner and outer surfaces which are preferably axially aligned. The stationary member 81 generally surrounds a fuel exit of the fuel injecting means, such as the fuel nozzle 21, and includes at least one and preferably a plurality of radially facing holes 82 therethrough, as can be seen in Figure 8.

The stationary member can be attached in any appropriate manner. For example, and as is shown in Figure 7, the stationary member 81 can, at its downstream edge be mounted to or be integral with thefirstannularflange32, and, at its upstream edge, it can be mounted to or be integral with an annular support plate 83. The support plate 83 preferably abuts the fuel nozzle 21. The support plate 83, the first annular flange 32, and the outer surface of the fuel nozzle 21 define an exit flowpath for turning the swirling air to flow from a generally radial direction to a generally axial direction and thereby enabling communication of air from the holes 82 with fuel exiting the fuel nozzle 21.

The swirler 80 also includes a movable member 90, preferably having generally cylindrical shaped radially inner and outer surfaces and which is disposed radially adjacent and preferably outward of the stationary member 81. As seen in Figure 8, the movable member 90 includes at least one and preferably a plurality of openings 91 therethrough which are communicable with the holes 82 in the stationary member 81.The movable member 90 includes a plurality of lips 92 which can be either planar or have a slight radially inward or outward curvature and which extend generally tangentially from the solid portion of the movable member adjacent the openings 91.Referring again to Figure 7, the movable member 90 can include at least one radially extending annular end plate 93, shown extending outwardly from the downstream edge thereof, to aid in channeling the air radially through the holes 82 and openings 91. In the arrangement shown in Figure 7, the annular support plate 83 extends radially outwardly a sufficient distance to also help channel air radially as well as to protect the stationary and movable members 81 and 90 from the stresses exerted by the compressed air.

The stationary and movable members 81 and 90 operate in the same manner as do the fixed and positionable members 30 and 40 of the first embodiment to vary the amount and direction or swirl angle of the discharge of air, and therefore that description will not be repeated.

To improve mixing of fuel and air, the direction of swirl rotation imparted by the stationary and movable members 81 and 90 can be made to be opposite to the direction of swirl rotation imparted by the fixed and positionable members 61 and 70 by arranging the lips 92 on the movable member 90 to extend oppositely from the lips on the positionable member 70. This can be seen in a comparison of Figures 6 and 8.

The means for adjusting the movable member 90 can be the same as or different from the means for adjusting the positionable member 70. For example, in Figure7, a single actuation arm 94 is attached at < - its radially inner end to the end plate 43 of the positionable member 70 and to the end plate 93 of the movable member 90. In this arrangement, movement ofthe actuation arm 94 adjusts both the movable member 90 and the positionable member 70. If desired, the end plates 43 and 93 can also be attached to each other. However, separate actuation arms can be employed to obtain separate adjustment ofthe movable and positionable members 90 and 70. Furthermore, the swirler 80 can comprise other combinations of fixed and positionable mem bers. For example, the fixed and positionable mem bers 61 and 70 shown in Figure 7 can be replaced by fixed and positionable members 30 and 40, such as those shown in Figure 1. Or, the stationary and movable members 81 and 90 shown in Figures 7 and 8 can be replaced by fixed and positionable members 61 and 70, such as those shown in Figure 6.

Claims

1. A flow modifying device of the type arranged for receiving fluid generally radially and discharging fluid generally axially, comprising: (a) a fixed member including a generally curved, axially aligned radially inner surface and at least one radially facing aperture therethrough, said fixed member further including axially directed discharge means; (b) a positionable member radially adjacent said fixed member and including at least one slot therethrough communicable with said aperture, adjustment of said positionable member being effective for varying the amount and direction ofthe discharge of said fluid from said flow modifying device; and (c) means for adjusting said positionable member.

2. The device of Claim 1 wherein said fixed member and said positionable member each include generally cylindrically shaped, axially aligned, radially inner and radially outer surfaces.

3. The device of Claim 2 wherein said positionable member is adjustable rotatably relative to said fixed member.

4. The device of Claim 3 wherein said fixed member includes a plurality of radially facing aper turestherethrough and said positionable member includes a plurality of slots thereth rough.

5. The device of Claim 4 wherein said axially directed discharge means comprises first and second annular flanges having generally curved, L-shaped cross sections and extending radially inwardly and axially downstream from the upstream and downstream edges respectively of said fixed member, said first and second annular flanges and said apertures defining a fluid flowpath therebetween.

6. The device of Claim 5 wherein said positionable member includes a plurality of lips extending tangentially therefrom, said lips overlying and being spaced radially outward of said slots for channeling fluid through said slots.

7. The device of Claim 6 wherein said positionable member further comprises annular, radially extending end plates protruding outwardly from the upstream and downstream edges of said positionable member.

8. The device of Claim 7 further comprising an annular, radially aligned disk attached with an upstream portion of said first annular flange and having at least one ducttherethrough for receiving said fluid from an axial direction and a gap therein for receiving a second fluid to be mixed with said fluid.

9. A swirler of the type arranged for receiving air generally radially and discharging air generally axially, comprising: (a) a fixed member aligned axially and including generally cylindrically shaped inner and outer radial surfaces and a plurality of radially facing apertures therethrough, and further including first and second annular flanges extending from the upstream and downstream edges respectively of said fixed member, said first and second annular flanges having generally curved L-shaped cross sections and extending radially inwardly and axially downstream from said fixed member;; (b) a positionable member disposed outwardly and radially adjacent said fixed member and including a plurality of slots therethrough communicable with said apertures of said fixed member and a plurality of lips extending generally tangentially from said positionable member for channeling air through said slots, and further including annular, radially extending end plates protruding outwardly from the upstream and downstream edges of said positionable member, said positionable member being rotatably adjustable relative to said fixed member for thereby varying the amount and swirl angle of air discharged from said swirler; and (c) means for rotatable adjusting said positionable member

10. The swirler of Claim 9 wherein said means for adjusting said positionable member comprises a drive arm connected with said positionable member.

11. The device of Claim 5 wherein said fixed member includes a plurality of lips extending tangentially therefrom and outward of said apertures for channeling fluid through said apertures and said slots.

12. The device of Claim 11 wherein said positionable member includes a plurality of curved protrusions extending radially therefrom for defining with said lips a fluid flowpath.

13. A swirler of the type arranged for receiving air generally radially and discharging air generally axially into a combustion chamber and disposed adjacent fuel injecting means, comprising: (a) a fixed member aligned axially and including generally cylindrically shaped inner and outer radial surfaces and a plurality of radially facing apertures therethrough, and further including first and second annular flanges extending generally radially inwardly and axially downstream from the upstream and downstream edges respectively of said fixed member and a plurality of lips extending generally tangentially from said fixed member for channeling airthrough said apertures;; (b) a positionable member disposed outwardly and radially adjacent said fixed member and including a plurality of slots therethrough communicable with said apertures of said fixed member, said positionable member being rotatably adjustable relative to said fixed member for thereby varying the amount and swirl angle of air discharged from said apertures into said combustion chamber;; (c) an axially aligned stationary member disposed upstream of said fixed member and generally surrounding a fuel exit of said fuel injecting means, said stationary member including generally cylindrically shaped inner and outer radial surfaces and a plurality of generally radially facing holes therethrough, and further including an annular support plate attached with the upstream edge of said stationary member, said annular support plate defining with said first annular flange a flowpath for enabling communication of airfrom said holes with fuel exiting said fuel injecting means;; (d) a movable member disposed outwardly and radially adjacent said stationary member including a plurality of openings therethrough communicable with said holes and a plurality of lips extending generally tangentially from said movable member for channeling air through said openings, said movable member being rotatably adjustable relative to said stationary member for thereby varying the amount and swirl angle of air discharged from said holes into said combustion chamber; and (e) means for rotatably adjusting said positionable member and said movable member.

14. The swirler of Claim 13 wherein said means for adjusting said positionable member and said movable member comprises a drive arm connected with said positionable member and said movable member.

15. The swirler of Claim 13 wherein said positionable memberfurtherincludes annular, radially extending end plates protruding outwardly from the upstream and downstream edges of said positionable member, and said movable member further includes an annular, radially extending end plate protruding outwardly from the downstream edge of said movable member.

16. The swirler of Claim 13 wherein said positionable member includes a plurality of curved protrusions extending radially therefrom for defining with said lips a fluid flowpath.

17. A flow modifying device substantially as hereinbefore described with reference to and as illustrated in the drawing.

18. A swirler substantially as hereinbefore described with reference to and as illustrated in the drawing.