US2839268A - Gas turbine - Google Patents

Description

June 17, 1958 R. c. ALLEN 2,839,268

GAS TURBINE Filed Jan. 18, 1950 2 Sheets-Sheet 1 @VA/g2 JI ai M June 17, 1958 R. c. ALLEN 2,339,263

GAS TURBINE Filed Jan. 18, 1950 2 Sheets-Sheet 2 United States Patent() GAS TURBINE Robert C. Allen, Wauwatosa, Wis., assignor to All s- Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application January 18, 1950, Serial No. 139,274

1 Claim. (Cl. 253-8915) This invention relates to elastic fluid turbines and similar bladed iuid flow machines and has for a principal object the provision of new and improved apparatus of this type. More specifically this invention relates to combustion gas turbines and its chief object is to make provision for cooling the blades thereof.

Another main object of this invention is the provision of a turbine rotor having a plurality of internal cavities defining a plurality of closed loop passages in which a fluid coolant circulates in one-way, well guided oW.

It has been proposed to provide an axial flow gas turbine blade having an internal cavity disposed in that part of the blade which extends into the hot motive uid l stream and also in that part of the blade which extends into a cooler zone, the cooler zone being disposed radially inward from the motive tluid stream, and the cavity containing a iiuid coolant which evaporates in the hot end of the cavity and iiows to the cooler end of the cavity where it co-ndenses and is iiung outward by centrifugal force. the abstracti-on of heat from that portion of the coolant disposed in an entire end portion of the cavity causes haphazard radially outward movements of condensed globules of coolant resulting in uneven cooling of the blade. lt is therefore an object of this invention to provide a turbine blade having a coolant containing internal cavity which will not be open to this objection. This invention contemplates rhe provision of a blade having an internal coolant containing cavity in the form of a closed loop passage which is disposed relative to a heat exchange device so arranged that heat will be abstracted from -that portion of the coolant disposed along `one radially extending side of the closed loop passage. Thus the density of this portion of the coolant will be increased above that in the remainder ot the loop passage so that this denser portion acts as a piston propelled by centrifugal force to push coolant to promote positive circulation of the coolant through the loop passage.

This invention also contemplates the provision of a turbine rotor having a plurality of internal coolant containing cavities in the form of endless closed loop passages Such an arrangement is open to the objection that' 2,839,268 Patented June 17, 1958` elastic uid turbine showing a second embodiment of this invention;

Fig. 4 is a fragmentary side View of the turbine rotor shown in Fig. 3; and

Fig. 5 is a fragmentary top view of the turbine rotor shown in Fig. 3. p

Referring to Figs. l and 2 of the drawings, a gas turbine is shown as comprising a turbine rotor structure 1 comprising a plurality of blades 2 (only one of which is shown) circumferentially spaced about and secured to the periphery of a rotatable member here shown as a disk 5. The rotor is encompassed by a stationary casing 3 to which motive iluid is supplied from a combustion chamber (not shown) through an annular passage 4 from ICC lwhich it is directed against the turbine blades 2 by an annular turbine nozzle 6 of any suitable construction.

Since the eliiciency of a gas turbine increases generally as the temperature of the motive uid increases, it is desirable to operate the turbine With a motive uid temperature as high as is commensurate with satisfactory blade life.

To this end, cooling means have been provided for the turbine blades 2 so that the blades may withstand high motive fluid temperatures'. An annular heat exchange structure 7 is disposed adjacent the upstream or high temperature end of the rotor 1 and is arranged to abstract heat from a tluid coolant contained within a closed loop passage 8 formed partly in the blade 2 and partly in the disk 5. l

The blade 2 may be of any suitable contour and is here shown as having a standard airfoil section and being fusibly united with the peripheral portion of the disk 5 by means of a weld 9. The blade 2 is relatively thin between its leading and trailing faces compared to its chordwise length. The closed loop passage 8 comprises a pair of parallel substantially radially extending bores 11, 12

, passing through the blade 2, the weld 9 and into the peripheral portion of the disk 5. The bores 11, 12 are connected at their inner extremities by an axially extending bore 13 formed in the disk 5 and at their outer end portions by an axially extending bore 14 formed in the blade 2. Communication between the bores 11, 12, 13, 14 and the atmosphere is prevented by sealing means such as plugs 16 disposed in the ends of the bores and secured by welding or the like; thus the interconnected bores 11, 12, 13, 14 form the closed loop passage 8 for containing the coolant. The bores 11, 12, 13 and 14 have a cross sectional coniiguration that is circular.

The material employed as a coolant within the passage 8 will be selected to be uid under operating conditions` and will vary with the design of each turbine. Substances which may be used include metals such as cadmium,

which will insure well guided circulation of the coolant. f

Other objects will appear hereinafter as the description of the invention proceeds.

The novel features of the invention and how the objects are attained will appear more fully from this speciiication and the accompanying drawings showing two embodiments of this invention and forming a part of this application, and all the novel features are intended to be pointed out in the claim.

ln the drawings:

Fig. l is a fragmentary axial section of an elastic uid turbine embodying this invention;

Fig. 2 is a plan view looking down on the tip of a blade shown in Fig. l;

Fig. 3 is a fragmentary axial section of the rotor of an mercury, gallium and lead. It would be desirable to use a material which would be liquid but which would not vaporize at operating temperatures to obviate the building up of vapor and gas pressure within the lblade 2.

The heat exchange structure 7 may be `of any suitable form and is here shown as a generally annular member 17 secured to the casing 3, disposed substantially parallel to the upstream face of the rotor 1 and provided With an annular passage 18 through which a uid cooling medium (for example, air, water or fuel oil) is circulated. Cooling medium supply means may comprise a conduit 19 communicating with the annular passage 18 and with an outside source of cooling medium (not shown). A stufng box 21 is provided at the point where the conduit 19 passes through the casing 3 to prevent the escape of gases therefrom and a second conduit (not shown) may remove heated cooling medium from the passage 18 to insure circulation of the medium through the passage 18. A wall 22 of the annular member 17 disposed adjacent formed on theY upstreamendfof the disk 5. Running clearance is provided between the corrugated wall 22 and the bosses 23. It should be noted that as shown in the drawings the heatv exchange structure 7 is in relatively close proximity to bore 12 and relatively remote from bore 11 to provide a concentrated cooling effect upon one of the axially extending passages, namely bore 12.

With Ithis Yconstruction the disk radiates heat from the bosses 23 to the relatively cool cooling medium owing through the annular passage 18 in the member 17 and heat in turn ows by conduction from the coolant in the bore 12 to the disk 5; thus heat is removed from the cool` ant in oneradially extending leg of the coolant containi'ng passage 8 and is carried o by the cooling medium inthe heat exchange structure 7. Removal of heat from that portion of the fluid coolant which lies in the radially extending bore 12 will lower the temperature and increase the density thereof, the increased density of this portion resulting in its being centrifuged radially outward along the bore 12 forcing the hotter portions of the coolant before it and insuring a counterclockwise circulation of the coolant in the passage 8. As the coolant circulates through the outer portions of the passage ti, heat is trans- .ferred from the blade 2 to the coolant thereby appreciably reducing the temperature of the blade.

The modified construction illustrated in Figs. 3, 4 and 5 (in which parts corresponding to parts hereinbefore described are designated by corresponding numerals having the sutx a) is a departure from that shown in Figs. 1 and 2 in that a coolant containing cavi-ty 24 is formed partly within an outer portion and partly within a root portion of a blade 26. The root of the blade 26 may be formed in any convenient shape and is here shown as having axially extending splines 23 which coact with complementary axially extending grooves 29 formed in lthe peripheral portion of the disk 27. Concentric annular bosses 31 are formed on one side of the rotor partly on the roots of the blades 26 and partly on the disk 27. The heat exchange structure 7a functions in the same manner as the heat exchange structure 7 shown in Figs. 1 and 2, removing heat from that portion of the coolant disposed in the adjacent radially extending portion of the cavity 24 therebyincreasing the density thereof and insuring circulation of the entire coolant.

From theforegoing it will be seen that the structures herein described provide for uniform one-'way circulation of a coolant contained within the bladed rotary structure 1.

It will be apparent to those skilled in the art that the structures herein described provide new and improved means for cooling turbine blading and accordingly accomplish the objects of the invention. It will also be obvious to those skilled in the art that the illustrated embodiments may be changed or modified or features thereof, singly or collectively, embodied in other combinations than those illustrated without departing from the spiritof the invention or sacrificing all the features thereof and that accordingly the description herein is illustrative only and the invention is not limited thereto.

It is claimed and desired to secure by Letters Patent:

1n an elastic uid turbine, a bladed structure having relative to fluid tlow through said turbine axially facing upstream and downstream-faces and comprising a plurality of circumferentially spaced blades fastened to a rotatable member, a stationary heat exchanger disposed in close proximity to the upstream face of said bladedY structure, each of said blades being relatively thin between its leading and trailing faces compared to its chordwise length, said bladed structure having a plurality of closed loop passages each disposed' at least in part within one of said blades, eachof said loop passages comprising a rst radially extending cavity disposed in relatively close proximity to the upstream face of said bladed structure and said heat exchanger, a second radially extending cavity spaced a substantial distance away from said first cavity in a'direction away from said heat exchanger, said spaced blades and said first and second cavities extending radially outward a substantial distance beyond said heat exchanger, and said iirst and second cavities being connected together at their respective end portions by an axially extending cavity, each of said cavities having a cross sectional configuration that is circular, each of said cavities containing a coolant selected to be in a liquid state at turbine operating temperatures, said heat exchanger and said upstream face of said bladedV structure having interposed circumferentially extending corruga-k tions t'o provide concentrated cooling of said coolant in a portion of said first cavity in close proximity to said heat exchanger to cool said coolant in said portion of said cavity and increase the density thereof above that of sai-d coolant in the remainder of said closed loop passage whereby centrifugal force acting upon said coolant iny said portion of said rst cavity is increased and positive displacement and circulation of said coolant through said loop is promoted.

References Cited in the tile of this patent UNITED STATES PATENTS 1,114,564 Winkler Get. 20, 1914 1,306,470 Dady lune l0, 19.19 1,501,862 Midgley July 15, 1924 1,651,503 Belluzzo Dec. 6, 192,7 1,938,686 Brooke Dec. 12, 1933 2,141,401 Martinka Dec. 27, 1938 2,371,548 Saffady Mar. 13, 1945 2,404,334 Whittle July 16, 1946 2,407,164 Kimball Sept. 3, 1946 2,501,038 Franssen Mar. 21, 1950 2,605,081 Alford July 29, 1952 FOREIGN PATENTS Y 229,933 Switzerland Feb. 16, 1944 434,965 Italy May 7, 1949 597,556 Germany lune 2, 1934 610,737 Great Britain Oct. 20, 1948 953,269 France May 16, 1949

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