US2959919A - Gas impingement starter nozzle for turbines - Google Patents

Gas impingement starter nozzle for turbines Download PDF

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Publication number
US2959919A
US2959919A US706743A US70674358A US2959919A US 2959919 A US2959919 A US 2959919A US 706743 A US706743 A US 706743A US 70674358 A US70674358 A US 70674358A US 2959919 A US2959919 A US 2959919A
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United States
Prior art keywords
nozzle
turbine
gas
impingement
starter
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Expired - Lifetime
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US706743A
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English (en)
Inventor
Jacob A Chiera
Gedrewicz Bronislaus Joseph
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General Electric Co
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General Electric Co
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Priority to US706743A priority Critical patent/US2959919A/en
Priority to CH6791958A priority patent/CH367354A/de
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
    • F02C7/26—Starting; Ignition
    • F02C7/268—Starting drives for the rotor, acting directly on the rotor of the gas turbine to be started
    • F02C7/27—Fluid drives

Definitions

  • vention relates to a gas impingement starter in which a gas under pressure from an external source, e.g. compressed air, is discharged through a nozzleand impinged against the turbine buckets of the gas turblne to thereby initiate rotation of the turbine.
  • a gas impingement starter is referred to thereinafter as a gas impingement starter and the nozzle is referred to as a gas impingement starter nozzle.
  • a gas impingement starter construction has been proposed which utilizes high pressure air stored in cartrldges.
  • the high pressure air is discharged against the turbine buckets through a number of small apertures punched either in the outer turbine nozzle diaphragm or in the turbine shroud.
  • 1t is an object of the present invention to provide a gas impingement starter which efiiciently utilizes low pressure gas which is readily available from standard ground cart type compressors.
  • the low pressure gas is discharged through a plurality of gas impingement starter nozzles against the turbine rotor.
  • each of the nozzles with a relatively large cross-sectional area.
  • an increase in individual nozzle cross-sectional area results in a decrease in the useful velocity developed by the nozzle and available for conversion into rotational thrust. Consequently, it is necessary to reduce dissipation of such reduced velocity to a minimum. Therefore, it is another object of the present invention to provide a gas impingement starter nozzle in which dissipation of useful velocity is reduced to thereby permit the use of relatively large nozzle cross-sectional areas.
  • apertures in the cartridge starter construction referred to above are inefiicient, results in substantial aerodynamic losses and deleteriously affects normal turbine operation.
  • the apertures comprise nozzles of a design which varies substantially from the kind of nozzle design with which the turbine buckets are designed to operate efliciently. Consequently, a large part of the useful velocity is dissipated. Useful velocityis also dissipated due to changes in pattern of the gas flow after the gas is discharged from the apertures and before it is impinged against the turbine buckets.
  • Another object is to provide such a starter, which is simple and light in construction and is inexpensive to manufacture, which does not substantially weaken the structural strength of the turbine assembly, and which can be easily incorporated into conventional turbine assemblies without extensive modifications in aerodynamic design.
  • a gas impingement starter nozzle having a pair of walls, which lie in planes inclined in a direction having a tangential and an axial component, and
  • a pair of walls which lie in planes inclined in a direction having a radial component and an axial component.
  • the nozzle is located radially from the turbine nozzles and the inclination of the tangentially inclined walls approximates the exit angle of the turbine nozzles. More specifically a gas impingement starter nozzle is provided comprising aerodynamic, radial extensions of a pair of turbine nozzle partitions.
  • the air impingement nozzles discharge the gases into the turbine nozzle passages at a point aft of the leading on the turbine buckets. Consequently, dissipation of useful velocity is avoided.
  • the radially inclined walls restrict the cross-sectional area of the nozzle and direct the gases radially into the spaces between the nozzle partitions, the radial inclination of such walls being selected to impart to the discharged gases a minimum radial component with a minimum number of nozzles.
  • Fig. 1 is a section in elevation of a part of the gas turbine section of a small gas turbo-propeller engine of the type described in the above mentioned application and which embodies an embodiment of the present invention
  • Fig. 2 is a section taken along the line 22 of Fig. 1 transversely through the engine;
  • Fig. 3 is a section taken along the line 3--3 of Fig. 1;
  • Fig. 4 is a section taken along the line 4-4 of Fig. 1;
  • Fig. 5 is a section taken along the line 5--5 of Fig. 4;
  • Fig. 6 is a section taken along the line 66 of Fig. 4;
  • Fig. 7 is a view similar to Fig. 1 but in perspective.
  • Fig. 8 is a view similar to Fig. 1 of another embodiment of the invention, in which the aerodynamic extensions of the nozzle partitions forming a part of the air impingement nozzles are separated from such partitions;
  • Fig. 9 is a perspective view of a plurality of the separated partition extensions of Fig. 8 looking from an aft direction and with parts cut away.
  • Casing section 1 is a section of the gas turbine casing of an engine of the type described and shown in the above-mentioned application.
  • Casing section 1 is attached to a forward section of the engine casing by means of flange 3 (Fig. 1) and to an aft section of the engine casing by means of flange 3a.
  • Casing section 1 has a pair of circumferentially elongated housings 2 located on opposite sides thereof, each housing comprising an end wall 4, having an opening 5 therein, a top tapered wall 6 extending in a circumferential direction, a rear wall 8, a forward side wall 10 and an aft side wall 12.
  • Forward side wall 10 extends into flange 14, which is attached to casing 1, as shown.
  • Aft side wall 12 is inclined in an aft direction at 16 and then extends integrally into casing shell 1, as shown.
  • the circumferential direction measured from front wall 4 to rear wall 8 of each of the housings is opposite from the direction of rotation of the
  • Each housing is located over a circumferentially elongated slot 18 in the casing 1.
  • Each slot is defined by a forward bevelled edge 19, an aft edge 21, formed by the juncture of inclined wall 16 with casing 1, as shown in Figs. 1 and 7, and side edges 23 and 25 formed respectively by the juncture of the aft portion of rear wall 8 with casing 1 and the juncture of the aft portion of front wall 5 with casing 1.
  • Slot 18 provides communication between the manifold chamber 20 formed by the housing and the interior of the turbine casing 1. Actually, the slot is located under the inclined wall 16, as shown.
  • a plurality of second stage turbine nozzle partitions 22 are mounted in an inner annular diaphragm or band 24 (see Fig. 2) and an outer diaphragm or band 26, the latter band being in turn mounted in casing 1 by means of annular casing rabbets 28 and 30 (see Figs. 1 and 7) and cooperating annular outer band rabbets 32 and 34.
  • Casing rabbet 30 also cooperates with casing rabbet 36 4 to support the turbine shroud 38 of the second stage turbine rotor 40 through shroud rabbets 42.
  • each slot 18 has a circumferentially elongated slot 44 therein which partially overlaps, but is slightly offset in an aft direction from slot 18, as shown in Fig. 1.
  • An inclined wall 46 extends from the aft edge 45 of the slot 44 forwardly and radially outwardly over the slot 44, through the slot 18, into the housing 2 and along the inclined wall 16 of the housing.
  • Inclined wall 46 is substantially parallel with and disposed radially in wardly of wall 16 as shown.
  • Wall 46 joints band 26 at the aft edge 45 of slot 44.
  • Wall 46 has a radially outwardly extending lip 48 and extends over the circumferential length of slot 44, as shown.
  • the circumferential ends of wall 46 extend radially inwardly at 50 (see Figs. 2, 4, 5 and 6) to the circumferential edges 49 of the slot 44 to which they are joined, as shown, to form end walls 50.
  • Another inclined wall 52 extends from the forward edge 47 of the slot 44, forwardly and radially outwardly to the rabbet 32 to which it is joined, as shown.
  • Wall 52 is substantially parallel to wall 46.
  • the circumferential edges 54 (see Fig. 6) of wall 52 abut against the end walls 50.
  • Inclined walls 46 and 52 and end walls 50 form a circumferentially elongated hopper-like chamber or chute 56 providing communication between manifold chamber 20 of the housing and the interior of outer band 26.
  • Each of the seven nozzle partitions 22 mounted in the slotted portion of the outer band has an extension 58 extending radially outwardly through the outer band 26 and slot 44, through notches in wall 52 and through apertures in wall 46, as shown. Part of such extension extends through slot 18 in the casing and into the housing, as shown in Figs. 1 and 7. Extensions 58 divide the chamber 56 into a number of air impingement nozzles or nozzle passages 60 defined by a contoured pressure surface 62 (see Fig. 3) and a contoured suction surface 64 of adjacent extensions 58 and the parts of the inclined walls 46 and 52 located between such adjacent extensions.
  • Each air impingement nozzle passage provides communication between manifold chamber 20 and the main turbine nozzle passage 61 located between the main part of the adjacent nozzle partitions from which such adjacent extensions extend.
  • the throat 65 of such air impingement nozzle is formed by the forward and aft edges 45 and 47 of slot 44 and the portions of surfaces 62 and 64 aligned therewith.
  • Walls 62 and 64 of the air impingement nozzles impart to the compressed air a turning movement corresponding to that imparted by the turbine nozzle partitions to exhaust gases during normal turbine operation, and direct the compressed air in a direction having a tangential component (right-hand direction as viewed in Figs. 3 and 4) and an axial component (vertical direction in the plane of the paper as viewed in Figs. 3 and 4).
  • the airfoil contours of the pressure and suction surfaces of the nozzle partitions are designed to achieve maximum rotational thrust with minimum aerodynamic losses.
  • the walls 62 and 64 of the air impingement nozzles have the same contours, and hence have the same turning and exit angles and discharge the gas against the turbine 5, buckets at the same angle of incidence, optimum starting efficiency is obtained. Furthermore, the flow path of the jets of compressed air after they emerge from the air impingement nozzles and before they are impinged against the turbine buckets is not appreciably changed in pattern and direction and hence a minimum of useful velocity is dissipated.
  • inclined walls 46 and 52 The purpose of the inclined walls 46 and 52 is to restrict the cross-sectional area of the air impingement nozzles and to direct the compressed air radially into the turbine nozzle passages at the same time that the surfaces 62 and 64 turn it in a tangential direction.
  • walls 46 and 52 direct the gas in a direction having an axial and a radial component. It is desirable that the radial component be kept at a minimum because the force exerted thereby is wasted. However, a decrease in the radial component results in a decrease in the crosssectional area of the air impingement nozzle throat.
  • a minimum total cross-sectional area is required to produce sufiicient thrust to start the engine so that if the crosssectional area of each throat is decreased, the number of air impingement nozzles must be increased with the result that weight, cost of manufacture, aerodynamic losses and detrimental effect on turbine operation are increased.
  • the incline of walls 46 and 52 is selected to provide an acceptable radial component with a minimum number of air impingement nozzles.
  • the acceptable angle of inclination of the walls 46 and 52 to the turbine axis, which determines the magnitude of the radial component, varies according to the turbine design.
  • the air jet is introduced into the turbine nozzles aft of the leading edges thereof. It is desirable to introduce them close to the trailing edges to avoid radial dissipation of useful velocity after they emerge from the air impingement nozzle throats.
  • the walls 46 and 52 compensate for the decrease in structural strength due to slots 44.
  • extensions 58 can be separated from the turbine nozzle partitions from which they extend. Such an arrangement is shown in Figs. 8 and 9 in which the extensions comprise separate stub blades 84 which are mounted on Wall 16 and extend radially inwardly therefrom. They can just as well be mounted on the outer band 26, or a flange which is integral with or mounted in, the casing. They have the same contours as the nozzle partitions 22 except that a small part of the trailing edges thereof are cut away at 85 to facilitate assembly. Consequently, each stub blade constitutes a stub of a nozzle partition.
  • each stub blade 84 is offset slightly forwardly of its main nozzle partition 22, as shown.
  • the stub blades form part of the gas impingement starter nozzles.
  • Nozzle partitions 22 extend radially outwardly from diaphragm 26 at 82 only a short distance, as shown in Fig. 8. These slight integral extensions 82 also form part of the gas impingement starter nozzles.
  • the radially inclined wall 89 corresponds to wall 46 in Fig. 1 but is shorter. It is aligned with the inclined wall 16 of the housing as shown so that the two walls together form a radially inclined wall of the chute and gas impingement nozzles.
  • one wall of each nozzle assembly comprises the 6 pressure surface of an integral extension 82 of a nozzle partition 22 and its aligned stub blade pressure surface 86 and the other oppositely facing wall comprises the suction surface of an integral extension 82 of an adjacent nozzle partition and its aligned adjacent stub blade suction surface 88.
  • One radially inclined wall is formed by wall 52 as in Fig. 1 and the other is formed by wall 89 and wall 16.
  • stub blades 84 are separate from partitions 22, aerodynamically they are radial extensions thereof.
  • extensions as referred to herein is used in its aerodynamic sense to include both integral extensions of the type shown in Fig. 1 and separateextensions of the type shown in Fig. 8.
  • the radially inner edges of the stub blades should be close to the radially outer edges of integral extensions 82 and the edge of wall 89 should contact the edge of wall 16 to avoid loss of pressure.
  • the integral extensions 82 can be eliminated in which case stub blades 84 are extended further inwardly.
  • the surfaces thereof, which define the walls of the impingement nozzles need not have the exact contours as the turbine nozzle partitions, although it is preferred that they be airfoil surfaces and correspond to the surfaces of a conventional turbine nozzle partition.
  • they need not be curvilinear so long as they are inclined in a direction having a tangential and an axial component.
  • a tangential component is important in order that the jets be discharged against the turbine buckets at an acceptable angle of incidence, preferably at the same angle of incidence as that provided by the turbine nozzles. In such case the tangential angle of inclination is substantially equal to the exit angle of the turbine nozzle partitions.
  • the air impingement starter nozzles of the present invention operate efiiciently with low pressure gas provided by conventional ground cart type compressors.
  • Such compressors usually produce air at a pressure of between about 30 and pounds per square inch.
  • the invention is not limited to the use of such pressures.
  • the construction of the present invention is simple and inexpensive to manufacture. It requires in addition to conventional turbine parts only a pair of housings of simple construction, a pair of slots in the outer band, a pair of slots in the casing, a pair of inclined walls for each slot in the outer band and a number of elongated nozzle partitions.
  • a turbine assembly comprising a turbine casing, a plurality of nozzle partitions, an outer nozzle dia phragm, means for mounting said partitions in said diaphragm, means for mounting said diaphragm in said casing, said diaphragm having a slot therein, a pair of radially inclined walls extending radially outwardly and forwardly from said diaphragm to form a chute, the throat of which is defined by said slot, said nozzle partitions having aerodynamic extensions extending radially through said chute to divide said chute into nozzle spaces defined by adjacent surfaces of adjacent extensions and said walls, and means for directing a flow of gas under pressure into said nozzle spaces.
  • a turbine assembly according to claim 1 said casing having a housing defining a gas manifold, said casing having an opening therein providing communication between said manifold and the interior of said chute.
  • a turbine assembly comprising a plurality of nozzle partitions mounted in a nozzle diaphragm, said diaphragm having a circumferentially elongated slot therein, each of the aft and forward edges of said slot extending into a wall which simultaneously extends radially outwardly and forwardly to form an inclined chute having a throat which is defined by said slot, a plurality of said partitions having radial extensions which extend through said diaphragm, said slot and said chute, to

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US706743A 1958-01-02 1958-01-02 Gas impingement starter nozzle for turbines Expired - Lifetime US2959919A (en)

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Application Number Priority Date Filing Date Title
US706743A US2959919A (en) 1958-01-02 1958-01-02 Gas impingement starter nozzle for turbines
CH6791958A CH367354A (de) 1958-01-02 1958-12-31 Druckgas-Anlasseinrichtung an Gasturbine

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US706743A US2959919A (en) 1958-01-02 1958-01-02 Gas impingement starter nozzle for turbines

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3056580A (en) * 1959-04-09 1962-10-02 Gen Electric Gas turbine starter
US3098355A (en) * 1960-11-29 1963-07-23 Gen Electric Starter nozzle for gas turbines
DE1278183B (de) * 1965-08-02 1968-09-19 Rolls Royce Druckgasanlasseinrichtung fuer ein Gasturbinenstrahltriebwerk
US3451215A (en) * 1967-04-03 1969-06-24 Gen Electric Fluid impingement starting means
US3971209A (en) * 1972-02-09 1976-07-27 Chair Rory Somerset De Gas generators
US4092824A (en) * 1974-05-28 1978-06-06 Vereinigte Flugtechnische Werke-Fokker Gmbh Method of operating a turbine
US4430575A (en) 1982-03-30 1984-02-07 General Electric Company Turbine turning gear with hydraulic overspeed drive
US5042970A (en) * 1989-11-28 1991-08-27 Sundstrand Corporation Fast recharge compressor
US6644033B2 (en) * 2002-01-17 2003-11-11 The Boeing Company Tip impingement turbine air starter for turbine engine

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1289960A (en) * 1918-04-13 1918-12-31 John Taylor Gas-turbine.
US2457833A (en) * 1943-02-03 1949-01-04 Westinghouse Electric Corp Cartridge starter for combustion gas turbines
GB615689A (en) * 1946-07-16 1949-01-10 David Havelock Ballantyne Improvements in or relating to the starting of internal-combustion turbine plants
US2714802A (en) * 1948-10-25 1955-08-09 Solar Aircraft Co Air starter for gas turbine
GB778855A (en) * 1954-08-20 1957-07-10 Power Jets Res & Dev Ltd A turbine rotor for driving an impeller

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1289960A (en) * 1918-04-13 1918-12-31 John Taylor Gas-turbine.
US2457833A (en) * 1943-02-03 1949-01-04 Westinghouse Electric Corp Cartridge starter for combustion gas turbines
GB615689A (en) * 1946-07-16 1949-01-10 David Havelock Ballantyne Improvements in or relating to the starting of internal-combustion turbine plants
US2714802A (en) * 1948-10-25 1955-08-09 Solar Aircraft Co Air starter for gas turbine
GB778855A (en) * 1954-08-20 1957-07-10 Power Jets Res & Dev Ltd A turbine rotor for driving an impeller

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3056580A (en) * 1959-04-09 1962-10-02 Gen Electric Gas turbine starter
US3098355A (en) * 1960-11-29 1963-07-23 Gen Electric Starter nozzle for gas turbines
DE1278183B (de) * 1965-08-02 1968-09-19 Rolls Royce Druckgasanlasseinrichtung fuer ein Gasturbinenstrahltriebwerk
US3451215A (en) * 1967-04-03 1969-06-24 Gen Electric Fluid impingement starting means
US3971209A (en) * 1972-02-09 1976-07-27 Chair Rory Somerset De Gas generators
US4092824A (en) * 1974-05-28 1978-06-06 Vereinigte Flugtechnische Werke-Fokker Gmbh Method of operating a turbine
US4430575A (en) 1982-03-30 1984-02-07 General Electric Company Turbine turning gear with hydraulic overspeed drive
US5042970A (en) * 1989-11-28 1991-08-27 Sundstrand Corporation Fast recharge compressor
US6644033B2 (en) * 2002-01-17 2003-11-11 The Boeing Company Tip impingement turbine air starter for turbine engine

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CH367354A (de) 1963-02-15

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