Rotary kinetic fluid motors or pumps – With passage in blade – vane – shaft or rotary distributor...
Patent
1987-11-18
1989-04-04
Garrett, Robert E.
Rotary kinetic fluid motors or pumps
With passage in blade, vane, shaft or rotary distributor...
416 97R, 60 3929, F01D 518
Patent
active
048181781
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for cooling heat-stressed structural elements of turbomachines, an apparatus for the implementation of the said method, and a design for heat-stressed blades, in which cooling air flows past the inner wall of the blade and emerges through small openings in the casing of the blade in the vicinity of the boundary-layer.
In the case of stationary turbomachines, and those installed in land-, sea- and air-vehicles are drive-units, the fact that specific structural elements, such as blades and combustion-chambers, are highly stressed by a flow of hot gas frequently creates problems. In an aircraft power-plant, for example, both rotor- and stator-blades are swept by a flow of hot gas, the temperature of which may amount to 1380.degree. C., for example, in the starting phase and to 1170.degree. C. during cruising flight. At these temperatures the blades need cooling, so that they are not damaged, or even destroyed, by heat-stress. To this end, cooling air, at a temperature of 585.degree. C. during the starting phase and 470.degree. C. during crusing flight, and at a pressure of 29 and 11 bars respectively, is taken from the high-pressure compressor, for example and is delivered to the blades by means of a special insert.
It is the purpose of the invention to indicate a method and an apparatus whereby the specific cooling power for cooling the heat-stressed structural elements of turbomachines is increased without the need of separate power-driven cooling units.
According to the invention, this purpose is accomplished in that cooling air flows tangentially into a vortex-tube consisting of a cylindrical vortex-chamber having two choke-elements at the end-sections at a location between the said choke-elements that is in the vicinity of a one of said choke-element that has an orifice-plate-like inflow section. The flow, after entering the vortex-tube, is divided into two partial flows of cooling air, one of which, after flowing through the choke-element with the orifice-plate-like inflow-section, is cooled in relation to the temperature of the cooling air flowing into the said vortex-tube and is fed to the wall-surface to be cooled, while the other partial flow of cooling air is led away from the area of the structural elements. The structural elements to be cooled may be the combustion-chambers and/or the blades. The partial flow of heated cooling air emerging from the one choke-element may be fed to the main flow of gas. This not only lengthens the life of the blades, but also reduces the operating costs of the turbomachine. In the case of aircraft power-plants, for example, this arrangement makes it possible to increase the temperature of the main flow of gas, thus improving the efficiency of the power-plant. Alternatively, it is possible to increase the temperature of the combustion-chamber, thus increasing the efficiency of the turbomachine; or the blades may be located nearer to the combustion-chamber nozzles, making it possible to reduce the size and weight of the turbomachines or to use a less costly material for the blades. This again reduces costs.
It is also possible to use a vortex-tube with a diffusor. The result of this is that the air emerging from the two end-sections is colder than the air fed to the vortex-tube. The length of the said vortex-tube, and the magnitude of the diffusor-angle are dependent upon the predetermined pressure-difference, upon the gas-throughput, upon the temperature of the gas passed through, and upon the extent of the desired drop in temperature. In the case of a vortex-tube with a diffusor, the cooling air is also introduced tangentially into a cylindrical section of the vortex-tube, whereupon a partial flow of cooling air flows through the diffusor while the remaining partial flow of cooling air flows through an orifice-plate-like choke-element. The partial flows of cooled cooling air may be combined again and may be passed to the wall-surfaces to be cooled.
Additional characteristics of the invention are described in greater detail below in
REFERENCES:
patent: 2893214 (1959-07-01), Hendal
patent: 2955432 (1960-10-01), Hardebol et al.
patent: 3173273 (1965-03-01), Fulton
patent: 3361336 (1968-01-01), Foa
patent: 3550372 (1970-12-01), Craig
patent: 4330235 (1982-05-01), Araki
patent: 4540339 (1985-09-01), Horvath
Garrett Robert E.
Kwon John T.
Marresearch Gesellschaft fuer Forschung und Entwicklung GmbH
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