The invention is applicable to a gas turbine engine cooling system and more particularly to an improved apparatus for supplying cooling fluid to hot parts of the engine, specifically, the interior of the turbine blade.
It is widely recognized that the efficiency and energy output of a gas turbine engine can be improved by increasing the operating temperature of the turbine. Under elevated operating temperatures, gas turbine engine components such as the turbine rotors and blades are cooled by a flow of compressed air discharged at a relatively cool temperature. The flow of coolant across the turbine rotor and through the interior of the blades removes heat so as to prevent excessive reduction of the mechanical strength properties of the blades and rotor.
Therefore on the one hand the turbine operating temperature, efficiency and output of the engine are limited by the high temperature capabilities of the various turbine elements and the materials of which they are made. In general the lower the temperature of the elements the higher strength and resistance to operating stresses. On the other hand the performance of the gas turbine engine is very sensitive to the amount of air flow that is used for cooling the hot turbine components. The less air that is used for cooling functions the better the efficiency and performance of the engine.
To cool the turbine blades, a flow of cooling air is typically introduced. There are two ways to deliver cooling air to turbine blades. One is from stationary part and other is from rotating part. From a stationary part, the cooling flow is introduced with a swirl or tangential velocity component through use of a tangential on board injector with nozzles directed at the rotating hub of the turbine rotor. From a rotating part, a flow of cooling air is typically introduced at a lower radius as close as possible to the engine shaft, such as underneath of the rotor disk bore.
According to an embodiment disclosed herein, an apparatus for cooling a rotating part having cooling channels therein, the rotating part attaching to a disk rotating about an axis, the disk having a conduit for feeding a cooling fluid to the cooling channel is described. The apparatus has a first impeller rotating with the disk and in register with the conduit and an outer periphery of the disk, the impeller directing the cooling flow to the conduit.
According to a further embodiment disclosed herein, an apparatus for directing a cooling fluid through a conduit to a rotating part, includes a first impeller in register with the conduit, the impeller having a shape that changes the direction of cooling fluid that is rotating tangentially relative to the conduit to flowing axially to the conduit.
According to a further embodiment disclosed herein, a method of cooling a turbine blade disposed in a gas turbine engine is described. The method includes providing a broach slot for providing cooling air to a base of the turbine blade and turning cooling air from rotating tangentially relative to the slot to passing axially to the broach slot.
These and other features of the invention would be better understood from the following specifications and drawings, the following of which is a brief description.
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Some impellers 90 have a J-shaped body 105 that has a radially extending part 107 that extends axially aft from bore cover plate 95. The radially extending part 107 smooths into an extension 110 that is perpendicular to the part 107 and tangential to airflow 115 (moving counter-clockwise in this application though clockwise is possible in other applications) in the conduit 100. The extensions 110 about the bore cover plate 95 form an imaginary perimeter 120 about the interior of the bore cover plate 95 and are disposed at an angle of 0-5 degrees relative thereto. Each of the part 107 and extension 110 smooth into the bore cover plate 95 by means of rounded beads 125. The body 105 has a saddle 130 at an intermediary portion 135 thereof, at upper peak 140 and a lower peak 145. The cover plate 95 conforms to the shape of the saddle 125, the upper peak 140 and the lower peak 145 so that cooling air does not flow over the impellers 90, 150 only between them.
Some impellers 150 do not have an extension 110 to save weight and may be interspersed between impellers 90 that have the extension 110. Typically there is one impeller to direct air to each broach slot 85 (See
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By adding the impellers, the higher swirl ratio increases the pressure of the cooling air flow within the turbine rotor cavity before it enters a broach slot 85. The low entrance angle of the extension 110 of the impellers 90 relative to the cooling air flow A is very small, between zero and five degrees since this arrangement will produce the least flow loss. The idea is to turn flow from tangential to radial with minimum flow loss minimal heat gain. The extension 110 and the beads 125 are shaped to turn the airflow 115 with minimal flow losses and heat gains.
Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
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Number | Date | Country | |
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20130115081 A1 | May 2013 | US |