US3009320A

US3009320A - Fluid impingement starter for turbine engines

Info

Publication number: US3009320A
Application number: US820412A
Authority: US
Inventors: Paiement Philip Raymond
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1959-06-15
Filing date: 1959-06-15
Publication date: 1961-11-21
Anticipated expiration: 1978-11-21

Description

Nov. 21, 1961 P. R. PAIEMENT 3,009,320

FLUID IMPINGEMENT STARTER FOR TURBINE ENGINES 2 SheetsSheet 1 Filed June 15. 1959 flew i arraeuer- Nov. 21, 1961 P. R. PAIEMENT 3,009,320

FLUID IMPINGEMENT STARTER FOR TURBINE ENGINES 2 Sheets-Sheet 2 Filed June 15. 1959 JNVENTOR. PM! /P E. Pfl/EME/V 7' United h I 3,009,320 Patented Nov. 21, 1961 3,009,320 FLUID D/IPINGEMENT STARTER FOR TURBINE ENGINES Philip Raymond Iaiernent, Melrose, Mass, assignor to General Electric Company, a corporation of New York Filed June 15, 1959, Ser. No. 820,412 9 Claims. (Cl. 6039.14)

This invention relates to fluid impingement starters for turbine engines, and particularly to an improved retractable fluid nozzle for use in such starters.

Fluid impingement starters are widely utilized in turbine engines. According to present practice, a high pressure fluid is usually impinged upon the buckets of a turbine Wheel by means of a nozzle communicating with a duct defining a working fluid path through the buckets. The pressure and velocity of the fluid impinging upon the buckets causes the Wheel to rotate at a speed suflicient to induce self-sustaining operation of the engine.

In order to gain maximum starting effectiveness, it is desirable to place the starting nozzle between the partitions of the working fluid nozzle customarily located upstream of the turbine wheel, and extending into the Working fluid duct, so that the orifice of the starting nozzle is positioned in close proximity to the leading edges of the buckets.

However, such positioning of the starting nozzle within the working fluid path produces undesirable turbulence of the working fluid stream during engine operation, with consequent unbalanced vibratory excitation of the turbine buckets. For this reason, starting nozzles of the kind described are generally not allowed to protrude into the working fluid path, but terminate at the inner surface of the duct defining that path.

It is an object of my invention to provide a fluid impingement starter nozzle which is extendable into the working fluid path of an associated turbine engine for starting operation, and is retractable from that path during normal operation of the engine.

It is a further object of my invention to provide means for automatically extending such a starter nozzle into the working fluid path upon commencement of the starting operation.

It is still a further object of my invention to provide means for automatically retracting such a starter nozzle from the working fluid path upon completion of the start ing operation, as the operation of the associated turbine engine becomes self-sustaining.

Other objects and advantages of my invention will become apparent as the description proceeds.

Briefly stated, in accordance with one aspect thereof, my invention may be carried out in a preferred embodiment by providing a starter nozzle body which is slidable in a nozzle housing mounted in an opening in the working fluid duct of a turbine engine, so that the nozzle body may be extended into and retracted from the working fluid path. The housing is preferably positioned in an opening in a nozzle diaphragm placed upstream of the turbine wheel, and is mounted at such an angle that the nozzle body impinges starting fluid directly upon the leading edges of the turbine buckets when in the extended position. The nozzle body and housing are formed as a double-acting piston and cylinder having means to limit relative motion in either direction. Starting fluid of suitable pressure is supplied to the nozzle body through the housing from any desired source, and this fluid acts upon the body to automatically cause its extension into the working fluid path and toward the turbine buckets. As the turbine engine reaches a se1f-sustaining operating speed, the supply of starting fluid is shut oli, and compressed air bled from nor of duct 4 forming the working fluid path of the engine.

a turbine-driven compressor is supplied to the housing to automatically retract the nozzle body from the working fluid stream.

In alternative embodiments, extension and/ or retraction of the nozzle from the interior of the Working fluid duct is performed by means of a mechanically operated rod, which is actuated by any desired means forming no part of this invention. Mechanical actuating means may be combined with either of the fluid pressure actuating means of the preferred embodiment previously described, as desired in particular applications.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention, it is believed that the invention will be more clearly understood from the following description of a preferred and several alternative embodiments, referring to the drawings, in which:

FIG. 1 is a cross-sectional elevation of a preferred embodiment of my improved nozzle construction in a retracted position, showing a portion of an associated turbine engine, as viewed in a plane passing radially through the centerline of the engine;

FIG. 2 is a view similar to FIG. 1, but showing the nozzle in an extended position for a starting cycle;

FIG. 3 is a view taken along the line 3-3 in FIG. 1, looking radially into the engine, partially in section;

FIG. 4 is a pictorial view of the nozzle body of FIG. I, removed from the engine;

FIG. 5 is a cutaway pictorial view of the nozzle housing of FIG. 1, removed from the engine;

FIG. 6 is across-sectional elevation of an alternative embodiment of my invention in a retracted position, showing a portion of an associated turbine engine;

FIG. 7 is a view similar to FIG. 6, but showing the nozzle in an extended position for a starting cycle;

FIG. 8 is a cross-sectional elevation of a further alternative embodiment of my invention in an extended position for a starting cycle; and

FIG. 9 is a cross-sectional elevation of a still further embodiment of my invention in an extended position for a starting cycle.

Referring to FIGS. 1, 2 and 3, a preferred embodiment of my improved retractable nozzle is shown in operative relationship with a portion of an associated turbine engine generally designated 1. The engine includes a rotatably mounted turbine wheel 2, carrying a row of buckets 3 on its periphery. In conventional manner, air is taken from the atmosphere and compressed by a compressor (not shown) connected to be driven by turbine wheel 2, passed to fuel combustion means (not shown), and the resulting working fluid is delivered to buckets 3 through a duct generally designated 4, which defines the working fluid path of the engine. Only a portion of duct 4 is shown, comprising a composite nozzle ring 5, a nozzle shroud ring 6, and a turbine shroud ring 7. Working fluid passes to buckets '3 through duct 4 in the direction shovm by the arrow in FIG. 1. As a result, buckets 3 and wheel 2 are rotated in the direction shown by the arrow in FIG. 3, driving the compressor during operation of the engine. Rings 5 and 6 are secured to a row of nozzle partitions 8, forming a nozzle diaphragm for directing working fluid at the most favorable entrance angle into buckets 3. A portion of the outer engine casing is shown at 9. The turbirle engine is of a well known type forming no part of the present invention, and will not be further described.

To provide improved means in accordance with my invention for starting the engine, a nozzle body 12 is slidably mounted within a nozzle housing '13. Housing 13 is inserted through openings 14, 15 and 16, formed in casing 9 and in the members of composite ring 5, respectively, so that the housing communicates at one end with the inte- Inner end 17 of the housing is faired into the inner surface of composite ring 5, to avoid interference with the working fluid stream. The housing is welded or otherwise secured in fluid-sealing engagement with casing 9 and ring 5.

Any suitable source of compressed starting fluid (not shown) may be used, such as an air bottle, or a compressor carried by a ground cart. The starting fluid is admitted to housing 13 and body 12 through a conduit 18 and a manifold 19, arranged in serial flow relation and secured together in fluid-tight relationship by welding or other suitable means. A valve 20 of any desired type is placed in series flow relation in conduit 18 for controlling admission of starting fluid to manifold 19. The manifold is shown extended circumferentially about the engine, so that a plurality of starting nozzles may be provided, as desired.

Referring now to FIGS. 4 and 5, housing 13 is formed with an internal bore 24, and an internal flange 25 near end 17. Body 12 is formed with a starting fluid passage 26 therethrough. The body is also formed with a circumferential flange 27 at one end, and is received in sliding engagement by bore 24 and flange 25 within housing 13. A fluid-confining cylinder 28 (see FIG. 1) of variable volume is thus formed between the housing and body, the confronting annular faces of

flanges

25 and 27 comprising pressure reaction surfaces in the cylinder.

Housing '13 is also formed with a plurality of stop lugs 29 spaced about bore 24 and spaced longitudinally from flange 25. A radial opening 30 is formed through a wall of the housing between flange 25 and stop lugs 29.

Body 12 is assembled in bore 24 at end 32 of the housing, and the assembly is secured by means of a snap ring 33 secured in a notch 34 near the end of the bore. Snap ring 33 and stop lugs 29 thus limit the travel of flange 27 and body 12 relative to housing 13.

Referring again to FIGS. l-3, cylinder 28 is connected in fluid flow relation through opening 30 and a tube 36 with a compressor bleed tube 37. Tube 37 is connected with the engine compressor (not shown) to supply pressurized air to cylinder 28 during operation of turbine engine 1.

In operation, valve 20 is opened to begin a starting cycle. Pressurized starting fluid is admitted from conduit 18 to manifold 19, and thence to bore 24 of housing 13 and passage 26 of body 12. The unbalanced reaction of the starting fluid upon the reaction surface formed by flange 27 of body 13 drives the body from the retracted position of FIGS. 1 and 3 to the extended position of FIG. 2, also shown in dotted lines at 12 in FIG. 3. The reaction is unbalanced because atmospheric pressure prevails in compressor bleed tube 37 and cylinder 28, the compressor being stationary and inoperative at this time. Nozzle body 12 is thus automatically driven by admission of the starting fluid to its extended position in the interior of duct 4. Its motion is halted by lugs 29 as it reaches close proximity to the leading edges of buckets 3. Starting fluid issues through passage 26 directly upon buckets 3, in the direction shown by the arrows, causing their rotation with maximum effectiveness.

As buckets 3 and turbine wheel 2 increase in rotational speed, the engine compressor supplies compressed air to the fuel combustion means, and combustion is initiated in a conventional manner. As the operation of the engine becomes self-sustaining, and valve 20 is closed to discontinue the supply of starting fluid to the engine, the means previously described provide for automatic retraction of nozzle body 12 from the extended position of FIG. 2. Referring to FIG. 1, compressed air flows in tubes 37 and 36 in the direction shown by the arrows and is received by cylinder 28 through opening 30 from the engine compressor, as the engine accelerates to operational speed. This pressure produces an unbalanced reaction upon the confronting reaction surfaces of

flanges

25 and 27, urging body 12 from the extended position of FIG. 2 to the retracted position of FIG. 1. Snap ring 33 stops the motion of the body in this position, and it is retained in place during operation of the engine by a continued supply of air from compressor bleed tube 37.

An alternative embodiment of my invention is shown in FIGS. 6 and 7. The turbine engine associated with the starter nozzle is substantially the same as that shown in the embodiment of FIGS. 1-3, and will not be further described; similar parts of the engine are similarly numbered, but with the subscript a. In this embodiment, a nozzle housing 40 is itself radially slidable in

openings

41, 42 and 43 of casing 9a and the members of composite nozzle ring 5a, respectively. An inner end 44 of housing 40 is faired into the inner surface of ring 5a, to avoid interference with the working fluid stream when in the retracted position of FIG. 6.

Mechanical means are provided for extending and retracting the housing into the interior of duct 4a, comprising a rod 45 threaded at an end 46 into housing 40. The rod may be operated manually, or may be actuated by mechanical means of any suitable type, forming no part of this invention.

A nozzle body 48 is slidably mounted in a bore 49 of housing 40. Body 48 includes a starting fluid passage 50, and a flange 51 formed about an end thereof. A stop flange 52 is formed within bore 49 of the housing to limit motion of body 48 into the bore by interference with flange 51.

Following insertion of body 48 into bore 49, a snap ring 54 is inserted in a groove 55, formed about bore 49 and spaced from an end thereof. Ring 54 does not form a full circle, but is made with lesser arc length in order to permit fluid to flow freely therepast between bore 49 and body 48. The assembly is completed by a snap ring 56, which is inserted in a groove 57 at an end of bore 49. Ring 56 seals a space further defined by body 43, bore 49, and flange 51 to form a fluid-confining cylinder 58. Confronting faces of flange 51 and ring 56 form pressure reaction surfaces in cylinder 58.

Starting fluid from any desired source is supplied to bore 49 through a conduit 60, threaded into the bore at 61 and sealed by means of a nut 62 threaded on the conduit. A compressor bleed tube 63 is placed in fluid commuuication with cylinder 58 through a bore 64 formed in body 40. Bore 64 forms an opening 65 in the wall of bore 49, spaced between rings 54 and 56. Tube 63 is threaded into bore 64 and 66, and is sealed by means of a nut 67 threaded on the tube.

To initiate the starting operation, rod 45 is actuated to extend housing 40 into the position of FIG. 7 in the interior of duct 4a. Starting fluid is then admitted to bore 49 and passage 50 of body 48 through conduit 60, in the direction shown by the arrows in FIG. 7. The starting fluid produces an unbalanced reaction upon the reaction surface formed by flange 51, driving it to the right as viewed in FIG. 7. The pressure in cylinder 58 at this time is atmospheric, the engine compressor being stationary.

The movement of body 48 is halted by ring 54 in the position of FIG. 7, and the starting fluid is directly impinged upon buckets 3a to obtain maximum starting effectiveness.

As buckets 3a and the associated engine attain selfsustaining operational speed, the starting fluid supply is shut off, and compressed air is received in cylinder 58 through tube 63, bore 64, and opening 65 from the engine compressor, in the direction shown by the arrows in FIG. 6. The unbalanced reaction upon the reaction surface formed by flange 51 drives body 48 to the left as viewed in FIG. 6. The movement of body 48 is halted by flange 52 in the position of FIG. 6, and rod 45 may then be actuated to withdraw housing 40 from the working fluid stream in the interior of duct 4a.

A further embodiment is shown in FIG. 8, in an extended position for a starting operation. The components of the associated turbine engine are similar, and are similarly numbered, with subscripts b. In this instance, the nozzle housing is eliminated as a separate element. A nozzle body 70 is provided, which is radially slidable in

openings

71, 72 and 73 formed in casing 9b and composite ring 5b, respectively. Mechanical means are provided for actuating the nozzle body, comprising a rod 74, which may be operated manually or by any desired mechanism. Rod 74 is secured to body 70 by means of a bracket 75, fastened by welding or other suitable means. Rod 74 may be used both for extending and withdrawing body 70 in duct 4b; however, body '70 is formed to be automatically extended by the admission of starting fluid thereto, and rod 74 need not be actuated to perform this function.

In order to provide for its automatic extension upon initiation of the starting cycle, body 70 is formed with a curved fluid passage 76 terminated in an end wall 77 and an orifice 78. A starting fluid conduit 79 is slidably received in passage 76. As starting fluid is admitted to passage 76 in the direction shown by the arrows to commence a starting cycle, the unbalanced reaction of the starting fluid upon the reaction surface formed by end wall 77 drives body 70 radially inwardly in duct 41;. This motion is limited to the position of FIG. 8 by the abutment of bracket 75 upon casing 9b. Starting fluid is ejected from orifice 78 directly and in close proximity upon buckets 3b, again providing a starting operation of maximum effectiveness. As engine 112 reaches self-sustaining operational speed, body 70 is withdrawn from the interior of duct 4b by means of rod 74.

Still a further embodiment is shown in FIG. 9. The parts of the associated engine are similar, and are similarly numbered, with subscripts c. In this instance, extension and withdrawal of an arcuate nozzle body 80 are again automatically performed. Nozzle body 80 is provided with stop flanges 81 and 82 at the ends thereof, and with a starting fluid passage 83 terminating in an orifice 84. T facilitate assembly, flange 82 is formed as a separate ring, and is threaded on body 80 after assembly of the nozzle. Flange 81 is slidably received in fluid-sealing relation within an arcuate bore 85 of a nozzle housing 86.

Housing 86 is formed with at least one stop lug 89 spaced longitudinally along bore 85, to permit fluid flow therepast, while limiting movement of body 80 by interfering with flange 81. Housing 86 is further formed with a flange 90 at its inner end, faired into ring c and slidably engaging body 80 in fluid-sealing relationship. A fluidconfining cylinder 91 is thus formed between housing 86 and body 80, having confronting faces of flanges 90 and 81 as pressure reaction surfaces.

A starting fluid manifold 92 is connected in serial flow relation with bore 85 of housing 86 through a suitable Valve 93. A compressor bleed tube 94 is connected in serial flow relation with cylinder 91 through an opening 95 in housing 86, being secured in the opening by welding or other suitable means.

Operation is similar to that of the embodiment shown in FIGS. 1-5. To commence a starting cycle, valve 93 is opened to admit starting fluid from manifold 92- to bore 85 of housing 86 and passage 83 of body 80, in the direction shown by the arrows. The unbalanced reaction of the starting fluid upon the reaction surface formed by flange 81 drives body 80 toward the extended position shown in FIG. 9, the motion being limited by stop lug 89. The starting fluid then impinges upon buckets 30 from orifice 84, bringing the buckets and the engine up to selfsustaining operating speed. The starting fluid flow is then shut oif by closing valve 93. Pressure built up in the engine compressor is received in cylinder 91 through tube 94, and the unbalanced reaction upon the reaction surface formed by flange 81 drives body 8%) into the retracted position and out of the working fluid path in duct 40.

It will be apparent from the foregoing description that I have provided an improved retractable fluid impingement starter nozzle for a, turbine engine, having means for automatic extension into a working fluid duct for starting the engine, and for automatic retraction from the working fluid duct during operation of the engine to avoid interference with the flow of working fluid in the duct. It will also be apparent that my invention encompasses the use of alternative mechanical means for extending and retracting the starter nozzle, alone or in combination with automatic means. -It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that modifications may occur to those skilled in the art without departing from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A fluid impingement starter for use in turbine engines of the type comprising a working fluid duct and a turbine Wheel rotatably mounted in said duct; said starter comprising nozzle means including an extensible nozzle body movable into and out of the interior of said duct through an opening formed therein, said nozzle body formed with a fluid passage, and means for moving said nozzle body into an extended position in said duct for impinging a stream of starting fluid through said fluid passage upon said turbine wheel and for moving said nozzle body from the interior of said duct into a retracted position during operation of said turbine engine.

2. A fluid impingement starter for use in a turbine engine of the type comprising a working fluid duct and a turbine wheel rotatably mounted in said duct; said starter comprising a nozzle housing communicating with said duct through an opening formed therein, an extensible nozzle body received in said housing, said body formed with a fluid passage, means for extending said nozzle body into said duct for impinging a stream of starting fluid from said fluid passage upon said turbine wheel, and means for retracting said nozzle body from said duct during operation of said turbine engine.

3. A fluid impingement starter for use in a turbine engine of the type comprising a working fluid duct and a turbine wheel rotatably mounted in said duct; said starter comprising a nozzle body movable into and out of the interior of said duct through an opening formed therein, means for moving said body out of said duct.

to a retracted position during operation of said engine, said body formed with a reaction surface and with a fluid passage, a manifold in fluid communication with said fluid passage, and means for admitting starting fluid to said manifold for starting said engine; whereby starting fluid acts upon said reaction surface to move said body to an extended position in the interior of said duct for impinging a stream of starting fluid from said fluid passage upon said tunbine wheel.

4. A fluid impingement starter for use in a turbine engine of the type comprising a working fluid duct and a turbine wheel rotatably mounted in said duct; said starter comprising a nozzle housing communicating with the interior of said duct through an opening formed therein, a nozzle body slidably mounted in said housing, means for moving said body out of said duct to a retracted position in said housing during operation of said engine, said nozzle body formed with a pressure reaction surface and with a fluid passage, and means for admitting starting fluid to said passage; starting fluid admitted to said passage producing an unbalanced reaction upon said surface to extend said body from said housing into said duct for impinging a stream of starting fluid from said passage upon said turbine Wheel.

5. A fluid impingement starter as recited in claim 4, in which said nozzle housing is slidably received in said duct, together with means for moving said housing into and out of the interior of said duct.

6. A fluid impingement starter for use in a turbine engine of the type comprising a Working fluid duct and a turbine wheel rotatably mounted in said duct; said starter comprising a nozzle body movable into and out of the interior of said duct through an opening formed therein, said body formed with a fluid passage and with a circumferential flange, means for moving said body into an extended position in the interior of said duct for impinging a stream of starting fluid from said fluid passage upon said turbine wheel, and tube means for supplying compressed fluid to said circumferential flange to retract said body from the interior of said duct during operation of said turbine engine.

7. A fluid impingement starter as recited in claim 6, together with a nozzle housing, said body slidable in said housing, said housing and said body cooperating to form a fluid-confining cylinder partially defined by said circumferential flange, said tube means supplying compressed fluid to said cylinder to retract said body from the interior of said duct during operation of said turbine engine.

8. A fluid impingement starter for use in a turbine engine of the type comprising a Working fluid duct and a turbine wheel rotatably mounted in said duct; said starter comprising a nozzle housing communicating with the interior of said duct through an opening formed therein, a nozzle body formed with a reaction surface and with a fluid passage, said body slidably mounted in said housing for movement into said duct to an extended position for impinging a stream of starting fluid from said passage upon said turbine wheel and out of said duct to a retracted position, said housing and body cooperating to form a fluid-confining cylinder, tube means for supplying compressed fluid to said cylinder to move said nozzle body from the interior of said duct to said retracted position during operation of said turbine engine, and means for admitting starting fluid to said fluid passage for starting said engine, whereby starting fluid acts upon said reaction surface of said body to move said body to said extended position.

9. A fluid impingement starter, as recited in claim 8, in which said nozzle housing is slidably received in said duct, together with means for moving said housing into and out of the interior of said duct.

References Cited in the file of this patent UNITED STATES PATENTS 2,714,802 Wosika Aug. 9, 1955 2,929,206 Davenport Mar. 22, 1960 FOREIGN PATENTS 1,076,691 France Apr. 21, 1954