US2624173A

US2624173A - Heat insulating arrangement for a plurality of coaxial turbines having opposed flow through doubletier blading

Info

Publication number: US2624173A
Application number: US193181A
Authority: US
Inventors: David J Bloomberg
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1950-10-31
Filing date: 1950-10-31
Publication date: 1953-01-06
Anticipated expiration: 1970-01-06

Description

Jan'. 6. Y1953 D. J. BLooMBERG 2,624,173

HEAT INSULTING ARRANGEMENT F OR A PLURALITY OF COAXIAL TURBINES HMIING OPPOSED FLOW THROUGH DOUBLE-TIER BLADING David "l Bloom berg.

by -AJffJi/M'ZQQ His ttzorney.

Jan. 6, 1953 n. J. BLooMBERG 2,624,173

HEAT INSULATING ARRANGEMENT FOR A PLURALITY OF COAXIAI.. TURBINES HAVING OPPOSED FLOW THROUGH DOUBLE-TIER BLADING Filed Oct. 31. 1950 2 SHEETS- SHEET 2 `I n vent or: Davld Jloombefg.

Patented Jan. 6, 1953 HEAT INSULATING ARRANGEMENT FOR A PLURALITY F COAXIAL TURBINES HAV- ING OPPOSED FLOW THROUGH DOUBLE- TIER BLADING David J. Bloomberg, Newton,

General Electric Company,

New York Mass.. assignor to a corporation of Application October 31, 1950, Serial No. 193,181

(el. ca -49) 12 Claims.

The present invention relates to fluid pressure energy converting devices and more particularly to an improved turbine arrangement.

My improved turbine arrangement is particularly useful as an energy converting device for the propulsion of aircraft or torpedoes, and

is provided with features that are desirable and often necessary in other applications where selfoxidizing fuels, high temperature. and high degree of energy conversion are of importance. Among such uses to which my invention is particularly suited are special reversing turbines forl marine applications, generator drives for high altitude aircraft, and high capacity fuel pump drives for rockets, etc.

An object of the invention is to provide an improved turbine arrangement.

Another object of the invention is in the provision of a turbine having substantially balanced torque reaction or in which torque unbalance is substantially minimized.

Another object is in the provision of an improved turbine arrangement which is capable of converting large amounts of energy with turbine parts of minimum size and weight.

Still another object of the invention is in the provision of an improved turbine flow path for producing greater output and with improved efiiciency.

Still another object is in the provision of an improved flow path arrangement that permits the use oi higher operating temperatures than was previously possible.

Other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a view, partly in section, illustrating one embodiment of the invention; Fig. 2 is another sectional view showing a modified embodiment of the invention; Fig. 3 is a view showing the combined nozzle ring and casing structure of the arrangement shown in Fig. 1 (looking in the direction of the arrows 3-3) with the turbine rotor removed; and Fig. 4'is a view looking in the direction of arrows 4--4 in Fig. 1 showing the intermediate passage portions.

Referring to Fig. l, my improved energy converting apparatus, including a turbine, indicated generally at I, and gearing, indicated generally at 2 and 3, is connected to and arranged to supply power to contra-rotating shafts 4, 5 which are connected to any desired type of power consuming apparatus (not shown). A feature of the invention is in the provision of turbine apparatus having contra-rotating mechanically independent rotors 6, 1 each arranged to convert equal amounts of energy from motive iluid supplied to the turbine and to deliver the energy so converted to contra-rotating shafts l, 6, respectively, so that there is substantially lno resultant torque reaction therefrom.

Motive fluid under pressure and -at elevated temperature is supplied to independent nozzle boxes 8, 8a provided with inlet ports 9, 9a, re-

spectively. The apparatus utilized for producing the motive fluid forms no part of the present invention and is therefore not shown. It will be understood by those skilled in the art that the motive fluid may be supplied by any well known type of gas generating apparatus, combustion apparatus, or may be supplied byA chemical reaction.

Nozzle boxes 8, 8a are identical for all practical purposes and, as will be apparent by reference to Fig. 1, are angularly displaced from each other by approximately 180. to the walls of each nozzle box are nozzle portions Ill, I 0a, respectively, for expanding the motive fluid to a high velocity and for directing the motive fluid at a desired angle with respect to the turbine rotors 6, 1.

Referring now to Figs. 1 and 3. the nozzle boxes 8. 8a and the corresponding rings of nozzles I0, I0a., respectively, extend through an arc of approximately or less'and are displaced from each other by Still referring to Figs. l and 3, nozzle box 8, inlet connection 9 and nozzles I0 are carried by a casing member II which also carries an exhaust collector portion`A I2. Exhaust collector portion I2 is provided with an arcuate opening I3 which is angularly displaced from nozzles I0 by 180. Arcuate opening I3 admits motive iiuid discharged from turbine rotor 6 into exhaust collector I2 and, as indicated in Fig. 3, opening I3 extends through approximately 160 of arc or some smaller amount. Exhaust collector I2 is also provided with a discharge connection I4 having a-suitable opening therein for discharging motive fluid directly to the atmosphere or, if desired, for connection to a suitable exhaust conduit (not shown) for conveying exhaust motive fluid away from the turbine I.

In a similar manner, casing member IIa carries nozzle box 8a, inlet connection 9a, and nozzles Ilia all disposed in a similar manner with respect to an exhaust collector I2a having 'a similar opening I3a and exhaust connection Ila.

Another important feature of the invention is in the provision of two independent and concen- Suitably secured.y

- tric flow paths on each of the rotors 6 and 1.

lu- This ls accomplished by the provision of ap rality of turbine buckets I5 secured to rotor 6 and disposed to define independent flow paths I5a and I5b therethrough. A plurality of buckets I6 similarly disposed to denne independent paths from each other by 180 are provided for transin flow from bucket portions I5a to bucket Listings I6b and from bucket portions i60, to bucket portions Ib, respectively.

As clearly indicated in Fig. 4, passage portions I1 and I8 are arcuate portions each of which extends through approximately 160 of arc. Passage portions I1 and I8 are carried by an intermediate structural member I9 which is in turn supported by casing members I I. I Ia in a manner which will be apparent from Fig. 1.

Thus it will be apparent that two independent ilow paths are provided through the turbine portion of the apparatus and since inlet connections except with respect to direction of rotation, each rotor will produce equal power output at all oper tin conditions thereby insuring balanced to-.quegon the turbine casing. The nrst flow path is defined by nozzle box 8, nozzles I0, bucket portions I5a, intermediate'passage portion I1, bucket portions I6b, exhaust collector I2a, and the nuid is mially discharged through exhaust connection Ila. The other iiow path is from nozzle box 8a, nozzles Ilia, bucket portions 16a, intermediate passage portion I8, bucket portions I5b, exhaust collector I2 and the motive fluid is nally discharged from exhaust connection Il.

The initial portion of each ilow path is arranged to produce an axially inward direction of gas now; that is, nozzle I0, bucket portions I5a. intermediate passage I1, as well as nozzles I0a. bucket passages I8a and intermediate passage I8, each produce an axially inward flow from the upper iiow passageway of one rotor to the lower passageway of the opposite rotor. Those skilled in the art will appreciate that the arrangement described has another important advantage in Ithat the outer bucket ow path receives motiver fluid from nozzles AIll and the innermost bucket flow path handles gases only after they have been expanded through one of the turbine rotors 6, 1. The expansion process removes considerable energy from the motive fluid. This means that the relatively low stressed portions of the buckets, that is, portions lia, IBa. handle high temperature motive fluid, and that the more highly stressed portions of the buckets lso, lsb handle motive fluid at a reduced temperature. It will also be appreciated that the provision of dual opposed rotors will permit a lower rotational speed than that of a. corresponding single stage turbine designed to convert the same amounts of energy with the samewheel diameter. This lower rotational speed permits the use of the longer buckets as described herein without increasing bucket stresses beyond safe values. Furthermore, the lower rotational speed permits a lighterwheel and is more favorable to the prob- ,l lems connected with bearing design, design of 4

concentric expansion joint

20, 20a joining the casing walls with the bearing housings 2I, 2Ia, respectively. Bearing housings 2i, 2Ia are coaxial axially extending cylindrical portions having a plurality of axially spaced circumferentially extending grooves provided therein at the outer surface. Secured to rotors 6, 1 are shafts 23, 23a, respectively, which are rotatably supported by bearings 24, 24a, provided in housings 2i and 2Ia, respectively. .11. suitable seal 25 is provided between bearings 24 and rotor 6 and between bearings 24a and rotor 1 to minimize any tendency for motive iiuid to leak along the shafts 23, 23a and ultimately mix with lubricant supplied to the bearings, or to minimize any tendency for lubricant to leak past the bearings and along shafts 23, 23a into the turbine easings II, IIa.

Gearing

2, 3 is provided with casings 26, 26a which enclose and rotatably support gears 21, 28

and 21a, 28a, respectively. As illustrated in Fig. l, A

gear casings 28,` 26a are made in two pieces to facilitate inspection, assembly and disassembly. Wall portions of the casing members are provided with anged joints 30 and 30a for securing the two casing halves together by threaded fastenings 3|, 3| a.

Casing walls

26 and 29, and 26a and 29a rotatably support gears 21, 21a, 28, 28a and shaft 4 is connected to gear 28a by an intermediate shaft portion 32 having splined end portions 32a and 32h in a manner which will be apparent by reference to Fig. l. In order to provide stiffness and maintain proper alignment of

gearing

2 and 3, as well as for safety reasons, intermediate shaft portion 32 is enclosed by a cylindrical casing member 33 secured to casing

walls

29, 29a.

Casing wall portions

29, 29a are provided with coaxial, cylindrical portions 34, 34a extending toward turbine casings IIa, II, respectively. At the respective ends of cylindrical portions 34, 34a are provided flanges 35. 35a, respectively, for connection to corresponding ilanges 36, 36a of sleeves 31, 31a. Sleeves 31, 31a have an limer cylindrical surface that lits tightly against the outer cylindrical surfaces between

grooves

22, 22a of bearing housings 2|, 2Ia. The outer cylindrical surfaces ol' sleeves 31, 31a are so proportioned as to perform a relatively close push fit with the inner surfaces of cylindrical portions 34, 34a. Clamps 38, which may be of the quick disconnect type as described in Patent 2,424,436, issued to Crater, assigned to the assignee of the present application, are provided for securing

flanges

35, 36 and 35a, 36a together. It will be appreciated that such an arrangement provides ease of assembly or disassembly for the removal or assembly of gear casings 26; 26a with respect to turbine casings II, IIa. At the same time the tightly fitting surfaces of sleeves 31, 31a and bearing housings 2|, 2Ia and the cooperating

grooves

22, 22a provide an eiecgive seal against the outward leakage of lubricant from the interior of gear casings 26, 26a.

In operation, motive fluid is supplied to inlet connection 8 and nozzle box 8 under pressure and at elevated temperatures. The motive fluid is expanded through nozzles I0 thereby increasing the velocity of motive fluid and at the same time reducing its pressure and temperature. Nozzles I0 also direct the motive uid at high velocity at the properangle with respect to turbine bucket portions I 5a thereby causing rotor 6 to rotate and convert a portion of the energy contained in the motive iiuid into mechanical power which is supplied to shaft 4 through turbine shaft 23, intermediate shaft 32 and connected gearing 3. Fluid discharged from turbine buckets' Ila then flows through intermediate portion I1 and into turbine buckets I6b causing rotor 1 to turn in a direction opposite to that of rotor 8. Rotor 1 thereby converts an additional portion of the energy contained in the motive fluid into mechanical power which is supplied to shaft 5 through rotor'shaft 23a and connecting gearing 2. In a like manner motive fluid is supplied to inlet connection 8a. nozzle box 8a, nozzles IIIe, from which it flows through bucket portions I6a, intermediate passageway I8 and bucket passages Ilib with a portion of the energy contained in the motive fluid being converted by each of rotors 8 and 1 and ultimately delivered as useful power to shafts 4 and 5, respectively.

As already indicated, inlet connections 8, 9a are connected to the same source of motive iluid and since the ilow path through each rotor is substantially identical, each rotor will produce equal power output at all operating conditions thus insuring a substantially -balanced torque reaction on the turbine casing. Fluid discharged from turbine buckets Iib. I8b is received in exhaust collector passages I2, I2a. respectively, and is ultimately discharged through exhaust connections I4 and Ila, respectively.

Both rotors 6, 1 receivemotive fluid from nozzles I0, Illa into the passages deilned between adjacent bucket portions Iia, I8a, respectively. The motive fluid as it leaves the nozzles is at its maximum temperature as far as the turbine rotor is concerned, and thus it will be seen that this high temperature portion of the motive uid is handled entirely by bucket portions I5a and Isa. After the motive fluid has passed through the passages deilned by these bucket portions. the pressure and temperature of the motive fluid is considerably reduced. Bucket portions I5b and I6b handle motive fluid only at reduced temperatures. Thus it will be seen that operating temperature of the outer bucket flow path, that is, bucket passages I5a. 16a is highest where the stresses due to rotation of the rotor are considerably lower than the stresses that exist in bucket portions lib, I8b which handle only fluid at a lower temperature.

Fig. 2 shows a modified embodiment of the invention permitting the use of higher temperatures or higher pressures of the motive fluid atthe turbine inlets. Such an arrangement provides improved eillciency and, for a given physical size, increased output. Like elements employ the same nota-tions as used in Fig. 1. A

The arrangement shown in Fig. 2 diilers from -l that of Fig. 1 in two major respects. First. after passing through the inner and outer bucket passage portions I5a. IBa. |511, I6b, the motive uid is subsequently expanded through additional sets of nozzles and buckets. In addition, the various turbine rotors rotate in a common direction and are secured to a single common shaft.

Nozzle box 8, inlet connection 9 and nozzles III are as described in connection with Fig. 1 and in addition a second and independent chamber 40 having a second set of nozzles 4I and an inlet opening ,42 is carried by nozzle box 8. For reasons previously discussed in connection with opening I3 in Fig. 1, opening 42 is arcuate in shape, extendsthrough approximately 160 of arc or less and is displaced from nozzles III by 180. A similar chamber 40a comprising nozzles 4Ia and opening 42a is carried by and is similarly disposed with respect to nozzle box 8a. As is clearly indicated, nozzles I0 and |0a are disposed adjacent to bucket portions lia and Iic respectively. Openings 42 and 42a are disposed adjacent to bucket portions I 6b, I6b, respectively, for receiving motive fluid discharged therefrom. As indicated in the drawing. nozzles 4I and 4Ia extend through 360, or full arc admission is employed. If desired, nozzles 4I and 4I 1I can be arranged for partial arc admission. It will be understood by those skilled in the art that partial arc admission means that nozzles 4I and 4Ia extend through an arcuate `opening of something less than 360. If partial arc admission is employed, the disposition of arcuate nozzle portions 4I and 4Ia with respect to arcuate openings 42, 42a, respectively. is not critical.

Still referring to Fig. 2, intermediate section I9 carrying passage portions I1, I8 is similar to the arrangement described in connection with Fig; 1 and diifers therefrom only in that the intermediate flow path portions I1, I8 of Fig. 2 reverse the direction of flow therethrough because all rotor portions inFig. 2 rotate in the same direction.

Rotor 43, rotor 44 carrying buckets 45, and rotor 46 carrying-buckets 41 are carried by a common shaft, and therefore all rotate in the same direction. Rotor 43 has separate rotor portions 8a and 1a carrying buckets I5, IB, respectively.

In operation, motive iluid under pressure is supplied from a suitable source (not shown) to inlet connections 9. 8a, respectively. From inlet connection 9 the motive fluid ows into nozzle box 8 and is expanded by nozzles I0, thereby reducing its pressure and temperature and at the same time increasing the velocity thereof. The motive fluid at high velocity is then directed into bucket portions IBa which convert a portion of the fluid energy into mechanical energy for causing rotation of rotor 43 and shaft 48. The motive fluid is discharged from bucket portions I5a into intermediate passage portion I1 which, as previously indicated, reverses the direction of flow thereof and discharges the fluid into bucket portions I6b thus converting an additional portion of fluid energy under mechanical energy. As the iluid is discharged from bucket portion I6b, it is received-into the nozzle box 40a through arcuate opening 42a. The fluid is then expanded through nozzles 4Ia thereby reducing its pressure and temperature still further. It is then discharged into buckets 41 for the additional conversion of fluid energy into mechanical energy for driving rotor 46 and shaft 48. The motive iluid is then discharged from buckets 41 through opening Ilia into exhaust collector I2a from which it is discharged through opening I4a in the manner described in connection with Fig. 1 above. The motive fluid delivered to inlet connection 9a passes in a similar manner through nozzle box 8a, nozzles IIIa, bucket passages I8a, intermediate passage portion I8, buckets I5b, arcuate opening 42, nozzle box 40, nozzles 4I, buckets 45, throughs/opening I3 into exhaust collector I2 and discharge opening I4 to convert additional portions of fluid energy into mechanical energy for driving rotor 43, rotor 44 and shaft 48.

Thus it will be seen that the temperature of the motive fluid flowing through the innermost bucket flow passages, that is, bucket portions I5b,. I6b is considerably reduced in value as compared to the temperature of the motive fluid at the inlet or in nozzle box 8 and because of the energy converted by bucket portions I5a, ISa. Since the outer portions I5a, Isa of buckets I5, I8 re spectively, are the lowest stressed portions of thev bucket, my improved turbine arrangement willpermit the use of higher temperature motive uid than was heretofore possible. It will also 'be appreciated by those skilled in the art that the use of an increased temperature at the in1et to an energy converting device results in improved thermal efficiency. In addition, my improved turbine arrangement provides a rotor structure wherein the innermost portion of the bucket flow path, that is, bucket portions lib, |812 will operate at a lower temperature than conventional turbine arrangements employing motive iiuid atthe same inlet temperatures, thus permitting higher allowable stresses in the innermost bucket portions. An additional and important advantage of the lower temperature of the motive fluid in the innermost. portion of the bucket ow path is that my improved arrangement reduces the thermal strain or temperature gradient which may be imposed upon a turbine rotor under emergency operating conditions.

It will also be recognized that the two row rotor arrangement can be used as the first stage of a double flow turbine, as illustrated in Fig. 2, or the motive iiuid discharged from the respective sides of the two row wheel can be conveyed into a single receiver and then either exhausted or fed into other turbine stages for further expansion.

While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art 1that various changes and modifications may be made without departing from the invention and it is intended to cover in the appended claims all such changes and modifications as come within the true spirit and scope of the invention.

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

l. A fluid pressure energy converting device comprising walls defining a pair of independent inlet fluid passageways having axially spaced end portions, first and second rows of moving blades disposed between said end portions and each of said rows forming separate inner and outer concentric fiuid passageways, said outer passageways'being disposed adjacent to said end portions for receiving fluid discharged therefrom. and walls defining two independent arcuate fluid passageways between said rows of moving blades establishing a connecting iiow path between the outer concentric passageway of said iirst row of blades and the inner concentric passageway of said second row and between said outer passage- Way of said second row and said inner passageway of the rst row of moving blades.

2. Apparatus in accordance with claim 1 wherein said arcuate passageways are oppositely disposed and each arcuate passageway extends through an arc of less than 180.

3. Apparatus in accordance with claim 1 wherein said arcuate passageways are angularly spaced by 180 and each arcuate passageway extends through an arc less than 160.

4. A turbine apparatus comprising a pair of casing members each having an inlet connection in communication with nozzle means and having an exhaust connection in communication with a iiuid passageway within said member, a rotor, at least two rows of blading carried by said rotor, each row of blading having separate inner and outer concentric fluid passages, one of said rows of blading being disposed with its outer iiuid passage adjacent to the nozzle means associated with the iirst of said pair of casing members and with its inner passage addacent to the iiuid passageway associated with said first casing member.

the second casing member and second row of blading being similarly arranged,l first walls deiining an arcuate flow passage portion and establishing communication between said outer passage of said rst row of blading and the inner passage of said second row of blading, and second walls defining an arcuate flow passage portion establishing communication between the outer passage of said second row of blading and said inner passage of said first row of blading.

5. Apparatus in accordance with claim 4 wherein said nozzle means, said casing passageway, and said arcuate passage portions defined by said first and second walls extend through arcs less than the nozzle means associated with the iirst casing member, the outer concentric passage of the iirst row of blading, the arcuate passage portion deiined by said rst walls, and the passageway associated with the second casing member are disposed in substantial alignment to form a first flow path extending in a generally axial direction; the nozzle means associated with the second casing member, the outer concentric passage of the second row of blading, said arcuate passage portion defined by said second walls and the passageway associated with the iirst casing mem-ber being disposed in substantial alignment to form a second iiow path extending in a generally axial direction and angularly spaced from the first ow path.

6. A turbine apparatus comprising a pair of casing members each having an inlet connection in communication with nozzle means within said members and having an exhaust passageway therein, first and second rotors carrying a, double tier row of blading each forming separate concentric inner. and outer fluid passages, each of said rotors being rotatably supported in one of.

said casing members with its outer concentric passage adjacent to the nozzle means associated with one of said casing members for receiving motive fluid issuing from said nozzle means and with its inner concentric passage adjacent to the exhaust passageway associated with said one casing member for-discharging motive iiuid into said passageway, walls defining a first arcuate fluid passage portion between the blading carried by said rotors and communicating with the outer concentric passage carried yby the first rotor and with the inner concentric passage carried by the second rotor, and other walls defining a second arcuate fluid passage portion between the blading carried by said rotors and communicating with the outer concentric passage carried by the second rotor and with the inner concentric passage carried by the first rotor.

7. Apparatus in accordance with claim 6 -wherein the nozzles associated with the iirst casing member, the outer concentric passage carried by the first rotor, said firstV arcuate passage portion, the inner concentric passage carried by the second rotor, and the exhaust passageway associated with the second casing member are disposed in substantial alignment to form a first flow path, and the nozzle means associated with the second casing member, the outer concentric passage carried by the second rotor, said second arcuate passage portion, the inner concentric passage defined by the blading carried by the first rotor, and the exhaust passageway associated with the iirst casing member are disposed in substantial alignment to form a second flow path.

8. Apparatus in accordance with claim 7 wherein said rotors rotate in opposite directions.

9. Apparatus in accordance with claim 8 wherein said rst and second arcuate passage portions extend through an arc less than 160.

10. Apparatus in accordance with claim 8 wherein said nozzle means, said exhaust passageways, and said first and second arcuate passage portions extend through arcs less than 160 and said first and second flow paths are angularly displaced by substantially 180.

11. Apparatus in accordance with claim 10 and including a, pair of coaxial output shafts, gearing connecting the first rotor to one of said shafts, and other gearing connecting the second rotor to the other of said shafts.

12. Apparatus in accordance with claim 11 wherein said coaxial shafts rotate in opposite 15 directions.

DAVID J. BLOOMBERG.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 996,324 de Ferranti June 27. 1911 1,820,725 Bailey Aug. 25, 1931 FOREIGN PATENTS Number Country Date 277,016 Germany July 24, 1914 425,945 France Apr. 19. 1911