US2711072A

US2711072A - Combustion chamber fairing

Info

Publication number: US2711072A
Application number: US231486A
Authority: US
Inventors: John M Wetzler
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1951-06-14
Filing date: 1951-06-14
Publication date: 1955-06-21
Anticipated expiration: 1972-06-21

Description

muy A June 21, 1955 Filed June 14, 1951 J. M. WETZLER 2,711,072

COMBUSTION CHAMBER FAIRING 2 Sheets-Sheet l June 21, 1955 M, WETZLER 2,7ll,072

COMBUSTION CHAMBER FAIRING Filed June 14, 1951 2 Sheets-Sheet 2 Ltjornegs Unite tates Patent aan COMBUSTION CHER FAIRING .lohn M. Wetzler, Indianapolis, Ind., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application .lune 14, 1951, Serial No. 231,436

7 Claims. (Cl. (itl-39.37)

This invention relates to combustion chambers of a type suited for use in gas turbine engines or the like, and, more particularly, to cannular-type combustion chambers.

The cannular-type combustion chamber, in contradistinction to the arrangement of a plurality of individual combustion chambers commonly used heretofore in gas turbine engines, is a single annular chamber of relatively large diameter in relation to that of said individual combustion chambers and is constituted by concentric cylindrical outer and inner casings between which a plurality of inner combustion liners are mounted. Though possessing certain structural and operating advantages, the cannular combustion chamber presents a dimcult problem with regard to the maintenance of a straight line air flow past the inner liners thereof. The compressor discharge air in passing through the combustion chamber inlet casing into the combustion chamber tends to swirl and creates an undesirable cross-flow condition across the inner liners so as to interfere with the combustion process and reduce the operating efficiency of the engine. This condition is not encountered or is, at least, substantially mitigated in gas turbine engines employing a plurality of individual combustion chambers.

The present invention aims generally toward improving the air flow in cannular-type combustion chambers, and has as its principal objective the provision of a cannular combustion chamber which simulates the action of individual combustion chambers and substantially prevents the establishment of a cross-ow condition therein.

A further object is to provide suitable means adapted to be compactly embodied in a cannular combustion chamber for the accomplishment of these general ends without additional space requirements or modication of the engine.

The preferred manner in which these and other objects are accomplished and the advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a fragmentary sectional elevation of a combuston chamber inlet casing and the inlet end of a cannular combustion chamber embodying a preferred form of the invention, the section being taken in the plane 1 1 of Fig. 2;

Fig. 2 is a partial transverse section of Fig. 1 taken in the plane 2 2 thereof;

Fig. 3 is a fragmentary section of Fig. 2 taken in the direction 3 3 thereof; and

Fig. 4 is a perspective View of one of the elements of the present invention.

Referring to thedrawings, Fig. 1 is a fragmentary sectional elevation of a combustion chamber inlet casing j and the inlet end of a cannular combustion chamber 12 embodying a preferred form of the invention.

The inlet casing 10 forms the mid-frame, which is one of the main structural support members of a gas turbine m ICE Z end of the mid-frame is adapted to be connected to the discharge end of a rotary compressor (not shown) which may be of the multi-stage axial llow fluid dynamic type.

The mid-frame 10 may be a fabricated sheet steel structure formed by a cylindrical outer casing 14 and a frusto-conical inner casing section 15 the forward and aft ends of which are supported by axially-aligned disklike face plates 16 and 17. The inner casing section 15 is supported from the outer casing 14 by a plurality of equally spaced hollow radial support struts 20 which extend substantially throughout the length of the rearwardly-diverging annular compressor outlet diffusing passage 24 defined by the outer casing 14 and inner casing section 15. The support struts have a double-convex or lenticular cross section as shown in the sectional view of Fig. 3, some of the struts being radially aligned with mounting pads 25 disposed about the periphery of the outer casing 14.

Extending circumferentially about the interior of the forward end of the mid-frame 10 is the compressor outlet 26 formed by an annulus containing two stationary annular rows of discharge guide vanes or straightening vanes 2S, 29 mounted in concentric outer and inner shroud rings 31 and 32, respectively, the annulus being supported principally by the inner shroud ring 32 suitably secured to the forward face plate 16 and the inner casing section 15 as shown in Fig. l. Flanges 36, 37 are provided at the forward and aft ends, respectively, of the outer casing 14 of the mid-frame 10 to permit fastening thereof by bolts (not shown) to mating flanges on the compressor casing and combustion chamber assembly, respectively.

The cannular combustion chamber 12 comprises a split outer casing formed by a pair of semi-cylindrical segments which are bolted together and are concentrically disposed about a cylindrical inner casing 42. The outer and inner casings 40, 42 of the combustion chamber deline a large annular passage which contains a plurality of combustion chamber inner liners 44 disposed in a circular array and mounted in spaced relation therein, the inner liners being centrally aligned between and located behind adjacent support struts 20 of the mid-frame 10 as shown in Fig. 2. Bolting flanges 46, 47 extending about the forward ends of the outer and inner combustion chamber casings 40, 42, respectively, are provided to fasten the combustion chamber to the rear flange 37 and face plate 17 at the discharge end of the mid-frame, which supports the combustion chamber. The forward portion of the outer and inner combustion casings are faired outwardly and inwardly, respectively, to provide a smooth continuous transition between the diverging discharge end of the mid-frame 1t) and the inlet end of the combustion chamber as shown. y

The combustion chamber inner liners 44 each comprises a dome-shaped forward member 50 which forms a detach- I able cap for a cylindrical burner shell 52, the latter member extending axially of the combustion chamber and having perforations (not shown) about its periphery for purpose of admitting compressed air to support the combustion process taking place therein. The dome 50 of the inner liner has a flanged annular central opening 54 therein to receive the spray tip 56 of an L. shaped fuel nozzle 57 which extends forwardly into the mid-frame l() between adjacent support struts 20 thereof and emerges through an opening 53 in the outer casing 14 over which is bolted an external nozzle mounting flange 59 near the aft end of the mid-frame. The burner shells 52 of the inner liners 44 are supported in spaced relation between the outer 40 and the inner 42 combustion chamber casings by saddle support members @welded to the inner casing as shown in the transverse view of Fig. 2.

In accordance with the invention, the compressor discharge air is prevented from setting up a cross-ilow'condition across the domes of the combustion chamber inner liners by means of a combustion chamber fairing which is positioned in the .combustion chamber to simulatev the action of theairiiow in individual combustion chambers. The Ycombustion chamber fairing comprises aplurality of radialbames orow splitter plates S each disposed in the inlet end of the .combustion chamber i2 between adjacent inner liners so as toenclose the forward portion of each inner liner in a segmented annular compartment formed by a pair of adjacent splitter plates and a curved portion of the outer and-inner combustion chamber casings 4d and 42 as shown in Fig. 2.

One of the splitter plates is shown in perspective elevation in Fig. 4 as a thin plate having a recess or em bossment 66 therein to increase its rigidity,A the shape of the plate conforminggenerallyy with the contours of the inlet portion of the `combustion chamber. A mounting tab 68 formed at the trailing end of the outer extremity 70 of the splitter plate of Fig. 4 permits fastening thereof to the outer combustion chamber casing 4i? by means of a partially threaded bolt 73, the upper portion. `of which is threaded through a nut welded to-the vouter casing, the lower portion of the bolt 73 forming an unthreaded pin 76 of reduced diameter and extending internally-of the combustion chamber to engage analigned opening in a washer 77 welded to the mounting tab Vas shown in Figs. 1 and 2. A similar mounting tab 78 formed at` the inner extremity 80 of the splitter plate of. lidg.,4 and located between the forward and trailing edges. till, 52, respectively, thereof is adapted to be lsecured to the inner combustion casing 42 by a threaded bolt 83 associated with an aligned nut and washer 8S land 86 welded to the inner surface of the combustion chamber inner casing as shown in Fig. l.

The forward edge 8l of the splitter plate 65 is detachably mounted in a bracket connection 89 which is formed by a pair of juxtaposed spring metallic strips 9d, 9i and has bifurcations at each end thereof as shown in Fig. 3, the strips being seam-welded together betweenthe bifurcated ends of the bracket. bracket S9 is welded to the trailing edge of the inlet casing support strut 20 behind which the splitter plate is aligned. The bifurcated trailing end of the bracket constitutes a "knife-blade connection which resiliently engages the forward edge of the splitter plate and forms a v rigid support therefor. The innermost trailing edge of the splitter plate is detachably mounted in another knifeblade bracket connection 93 formed by a pair of spring metallic outwardly extending L-shaped strips 94, 9S welded to lthecornbustion chamber inner casing d?. as

shown in Figs. l, 2 and 3.

The splitter plates 65 and connecting brackets 59 conystitute an extension of the inlet casing support struts 2.@

into the combustion chamber so as to form an etective partition which substantially prevents the establishment of a cross-flow condition of the compressor discharge air across the inner combustion liners and maintains a straight line ow thereby. In the preferred embodiment of the invention, the splitter plates extend axiallyfrom the inlet of the combustion chamber slightly beyond the dome-shaped forward portion of the inner combustion liners, although the plates could extend substantially throughout the entire length of the combustion chamber if desired.

Although a specific embodiment of the invention has been shown and described, it will be understood that it is but illustrative and that various modiiications may be made therein without departing from the scope and spirit of this invention.

What is claimed-is:

1. In combination, a rotary compressor, a single annular combustion chamber, a combustion Achamber inlet casing between said compressor and combustion chamber, said inlet casing comprising a rearwardly extending annular diffusing passage having a plurality of radial- The forward edge of the ly disposed support struts therein, said combustion chamber comprising a cylindrical outer easing and a cylindrical inner casing concentric with said cuter casing, and akk plurality of cylindrical inner combustion liners mounted in spaced relation between said outer and inner combustion chamber casings, and apiurality of radially dis-V posed flow-splitter plates detachably mounted to respec casing between said compressor and combustion chamher, said inlet casing comprising a rearwardly extending annular ditusing passage having a plurality of radially radially disposed support struts therein, said combustion chamber comprising a cylindrical outer casing and a cylindrical inner casing concentric with said outer casing, and a plurality of cylindrical inner combustion liners mounted in spaced relation between said outer and inner combustion chamber casings, and a plurality of radially disposed dow-splitter plates extending axially of said combustion chamber between adjacent ones of saidinner combustion liners, the forward edge of each of said flow-splitter plates being detachably mounted in knife-blade bracket connections secured to respective ones of said inlet casing support struts.

3. In a combustion apparatus comprising, in combination, an outer casing and an inner casing coaxial with said outer casing and deiining therewith an axiallyextending annular passage having an inlet portion and an outlet portion at the respective ends thereof, a plurality of spaced burners extending axially of said passageand mounted therein between said outer and inner casings and a plurality of radially disposed iiow divider lplates positioned in the inlet of said passage between adjacent ones of said burners and extending axially of said passage,V

said iiow divider plates dividingthe inlet portion of said combustion apparatus into a plurality of compartments each containing one of said burners and simulating a plurality of separate combustion chambers in said cornbustion apparatus.

4. In a combustion apparatus comprising, in combination, an outer casing and an inner casing coaxial with said outer casing and deiinng therewith an axially extending annular passage havingk an inlet portion and an outlet portion at the respective ends thereof, a plurality of spaced burners extending axially of said passage and mounted therein between said outer and inner casings, and a plurality of detachably mounted flow divider plates radially disposed in the inlet of said passage between adjacent ones of said burners and extending axially of said passage, said ow divider plates dividing the inlet portion or" said combustion apparatus into a plurality of compartments each containing one of said burners andsimulating a plurality of separate combustion chambers in said combustion apparatus.

5. A gas turbine engine comprising, in combination, a turbine-driven compressor, a single annular combustion apparatus and an annular inlet casing betweensaid compressor andk said combustion apparatus having passage means dened therein for supplying the combustion apparatus from the compressor, said combustion apparatus including an outer wall, an inner wall coaxial `with the f outer wall and deiining therewith a large annular coming axiallyfrom a point slightly forward ofsaid burners.

a part of the length thereof, said iow dividerrfvrneans dividing the interior of said combustion chamber into a plurality of compartments each containing one of said burners and simulating a plurality of separate smaller combustion chambers in said large combustion chamber.

6. In a gas turbine engine including a turbine-driven compressor, a combustion apparatus and an inlet casing, said inlet casing defining an axially extending annular passage between said compressor and said combustion apparatus and having a plurality of radially disposed support struts therein, said combustion apparatus comprising, in combination, an outer casing wall, an inner casing wall coaxial with the outer casing Wall and defining therewith a large annular combustion chamber extending axially of the engine and having an inlet portion and an outlet portion, a plurality of spaced burners extending axially of said chamber and mounted between said outer and inner casing walls, a plurality of radially disposed ow divider plates in the inlet of said cornbustion chamber and positioned between adjacent ones of said burners, said iow divider plates being proximate to and aligned with respective ones of said inlet casing support struts and dividing the inlet of said combustion apparatus into a plurality of compartments each containing one of said burners, said compartments simulating a plurality of separate smaller combustion chambers in said large combustion chamber.

7. In a gas turbine engine including a turbine-driven compressor, a single annular combustion apparatus and an annular inlet casing between said compressor and said combustion apparatus, said annular inlet casing dening an axially extending annular passage between said compressor and said combustion apparatus and having a plurality of radially disposed support struts therein, said combustion apparatus comprising in combination, an outer casing wall and an inner casing wall coaxial with the outer casing wall and defining therewith a large annular combustion chamber extending axially of the engine and having an inlet portion adapted to be connected to said annular inlet casing and an outlet portion, a plurality of spaced burners extending axially of said combustion chamber and mounted between said outer and inner casing walls thereof, and a plurality of radially disposed How-splitter plates in the inlet of said combustion chamber and positioned between adjacent ones of said burners, each of said flow-splitter plates being adapted to be connected at its forward end to a respective one of said inlet casing support struts and extending axially of said combustion chamber a part of the length of the burners therein.

References Cited in the tile of this patent UNITED STATES PATENTS 2,479,573 Howard Aug. 23, 1949 2,545,495 Sforzin Mar. 2l, 1951 2,548,886 Howard Apr. 17, 1951 2,595,999 Way et al May 6, 1952 FOREIGN PATENTS 936,276 France Feb. 16, 1948