US2894719A - Improved strut supported turbine blade - Google Patents

Description

D. v. FOSTER 2,894,719

l IMPRovED sTRuT sUPPoRTED TURBINE BLADE Filed Feb. 21, 1956 July 14, 1959 United ares Pate@ t MPRGVED STRUT SUPPORTED TURBINE BLADE Douglas V. Foster, Kansas City, M0., assign'or, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application February 21, 1956, Serial No. 567,040

2 Claims. (Cl. 253-3915) The present invention relates to improved cooling means for turbines and turbine blading.

It is an object of this invention to provide improved cooling means for turbine struts whereby the cooled air is kept at a It is -a further object of this invention to provide a specific construction of cooling means for turbines thereby reducing ya portion of the high precision machining and assembly ordinarily necessary in the manufacture of turbine blading.

It is an additional object of this invention to provide cooling means for a turbine wherein the amount of cooling air used is reduced but on the other hand the cooled area is increased.

These and other objects will be readily apparent to those skilled in the art from a reading of the following specification and yan examination of the attached drawings, wherein:

Figure 1 is lan isometric view of the present design of blading,

Figure 2 is an isometric view iof the proposed blading of the instant invention, and

Figure 3 in an enlarged view -along section line 3--3 of Figure 1.

vFigure 4 is an enlarged view along section line 4 4 of Figure 2.

In conventional turbine design, cooling means for the turbine is a necessity because of the large increase of the maximum cycle temperature. However, the cooling air is desired to -be maintained `at a minimum as a result of two reasons:

(a) The thrust is reduced approximately in proportion -to the amount of cooling air used, and

(b) At high ight speeds of aircraft, refrigeration of the cooling air is necessary; consequently, the less cooling air required, the less refrigeration apparatus required and Iit naturally follows the less it will weigh.

In one form of cooling system used in the cooling of turbine blades and struts, as shown in Figures 1 and 3, the blade 1 consists of a central tubular strut 3 enveloped by a non-load carrying sheath 2. The sheath is attached to the central tubular strut by means of webs 5; ns 4 are mounted on the central tubular strut between each pair of webs and betwix-t the strut and shroud. Cooling air is passed through the blade in any conventional manner thus cooling both the strut and the shroud. The cooling of the strut is augmented by the use of the cooling ns as is well known.

There are many means for supplying the cooled fluid, as for example, by having the uid pass through a refrigerator 6, and pump 7. It is of course understood that numerous other means are Well known in the art.

In the present invention, as shown Iin Figures 2 and 4, the blade 10 consists of a central tubular load supporting strut 13 and an enveloping shroud 12 attached to the strut by means of webs or tins 15. Located in the spaces 18 created by the strut, shroud and each pair of webs is a wall 16 parallel to the strut and shroud and spaced from both of them by means of the cooling fins 14 secured to the strut. It is thus seen that with the above construction, a plurality of U-shaped members are formed with their bases 19 parallel to the strut so that cooling pockets or bights 17 are created adjacent the strut.

Cooling air is pumped through the cooling pockets or bights 17 adjacent fins 14 and betwixt wall 16 and the strut; the strut is -thereby cooled and the cooling action is augmented by the cooling action of the fins 14.

It is evident from the present construction that the amount of the cooling air ow is reduced in view of removal of the cooling action on the outer shroud; the amount of the cooling air is further reduced by the increased cooling `iin area for a given shell supporting iin pitching.

It is also seen that by the use of the improved cooled blading system, the cooling fins 14 can be attached together by means of the common Wall 16. As a result, fewer parts have to be held in an accurate relative position during the assembly operation.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is Itherefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specically described.

What is claimed is:

l. A turbine blade comprising a central tubular strut; a shroud; means attaching said shroud to said strut whereby the shroud encircles the strut and forms a space between said strut -and said shroud; a wail Within said space disposed parallel to the strut and spaced from both the shroud and the strut; spaced fins connecting said wall to said strut so that cooling pockets are formed adjacent the strut; means for introducing a cooling uid into the cooling pockets dened by the wall, the ns and the stmt so that the central strut is cooled.

2. A turbine blade comprising a central tubular strut; a shroud; web means connecting the shroud to the strut in spaced relation thereto; U-shaped members attached to the strut in the space dened by the shroud and the strut, said U-shaped members having their bases disposed substantially parallel to the strut and spaced hom both the shroud and the strut; and means to pass a cooling uid through the ibight of said U-shaped members so that the central strut is cooled.

References Cited in the le of this patent UNITED STATES PATENTS 2,369,795 Planiol Feb. 20, 1945 2,506,581 Cowles May 9, 1950 2,568,726 Franz Sept. 25, 1951 2,648,520 Schmitt Aug. 11, 1953 2,708,564 Erickson May 17, 1955 2,742,274 Lachmann Apr. 17, 1956 OTHER REFERENCES 625,693 Great Britain July 1, 1949 736,800 Great Britain Sept. 14, 1955 738,213 Great Britain Oct. 12, 1955 740,597 Great Britain Nov. 16, 1955

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