This invention relates generally to gas turbine engines and, more particularly, to the cooling of HPT-LPT discs and the blades on the discs.

In known gas turbine engines, the thrust to turn the turbine blades is obtained by the energy created by combining the compressed air from the high-speed compressor with the fuel mixture inside the combustor. The turbine blades need to be cooled because the high temperature of about 1700 degrees which occurs with the combustion in the boiler, as the metal alloy turbine blades can not withstand such heat. If we think that the cooling air required for internal cooling of the turbine blades is 20% air stolen from the high-speed compressor (core motor), it is easy to see how important this amount of air is to obtain power from the turbine. As 20% of the engine power of the compressor to turn the turbine is actually used for cooling, 100% compressor air can not be utilized. Also cooling with a high-pressure 650-degree HPT air from the small hole under the rotating high-speed HPT disk blades and sending cool air from the air ducts between the turbine disks to the HPT disk negatively affects the spinning speed of the disks and puts stress on the turbine disks. In this cooling technique, when the compressed air of the high speed compressor hits the rotating HPT turbine disk, it reduces the speed that the turbine rotates, which is impossible to ignore in scientific terms. This impact causes the rpm of HPT turbine disk to decrease the number of revolutions (rpm) by approximately 5-10%.

Technical problems that are aimed to be solved with the invention

Instead of the conventional method of using some of the air from the HPT compressor of the turbine blades, this invention aims to do the cooling externally, using the air sucked by the fan stages added to the inlet of the LPT compressor fan shaft, with a much cooler air, requiring less energy and putting less stress on the overall system. Since the air passing through the shaft is

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SUBSTITUTE SHEETS (RULE 26) not overheated with this invention, the moisture will also be transferred to the blades, contrary to the conventional method of 650 degrees HPT compressor air, the cooling effect will be much better. Furthermore, the invention is also very convenient for the technique of cooling with air- water vapor (not shown in the drawings) by flowing water from the stator part of the cooling fan using the dripping technique. Water from the stator of the cooling fan turns into steam when it reaches the disks, leaving the blades and performing more effective cooling. Thus, 20% air stolen from the HPT compressor air for cooling is used to just drive the turbine blades, and not for cooling, thus, ensuring 100% utilization of HPT compressor (core motor) air. The load on the HPT and LPT disk and blades are reduced, as the high-pressure (core motor) compressor is fully utilized, and better engine power, fuel and strength advantages are obtained with less stress and tension. Turbine blades cooling technology for external gas turbine engines performed to achieve the purpose of the invention is shown in the following diagrams.

Explanation of the diagrams

Figure 1: The cooling scheme of the HPT and LPT turbine disk and blades with the external fan stages located in the entrance of the turbofan engine main shaft by extending it into a wider funnel shape.

Figure 2: External cooling fan shaft diagram

Figure 3: Fixing diagram for the external cooling fan spindle to the main shaft

Figure 4: Front view of the main shaft entry point

Figure 5: Fixing diagram for the external cooling fan spindle to the main shaft

Figure 6: Schematic diagram of air passageways to HPT and LPT discs through the main shaft Figure 7: The air flow diagram showing the cooling air passing through the turbine disks, below the blades and above the air duct of the disk, through the turbine disk blades

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SUBSTITUTE SHEETS (RULE 26) Explanation of the references in the diagrams

The descriptions of the numbers in the diagrams are given below:

1: Fan blades

2: External cooling fan shaft

3: External cooling fan casing

4: Air tightness bearing

5: Main shaft

6: Cool air passageways for HPT(HPT=High pressure turbine)

7: Cool air passageways for LPT(LPT=Low pressure turbine)

8: HPT Disk

9: LPTDisk

10: HPTDiskgap (for cool air flow)

11: LPTDiskgap(for cool air flow)

12: HPTblade

13: LPTblade

14: Internal blades to hold the shaft(4blades)

15: Air ducts (for HPT)

16: Air ducts(for LPT)

17: Shaft channel(4 channels)

18: External cooling stator

19: Engine casing

20: Air tightness bearing Explanation of the invention

Figure 1: The flow chart of the cooling air for the gas turbine engines.The external cooling fan stages (1) installed to the entry point of the engine main shaft (5), as the cooling air passes through axial passage in the main shaft (5), cooling air discharge holes (6,7), HPT (8), LPT (9) disks, radial passageway and the air ducts over the disks (15,16) and exits from the necessary points of the turbine blades (12,13).

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SUBSTITUTE SHEETS (RULE 26) Figure 2: Four channels (17) to fix the external cooling fan shaft (2) to the engine main shaft (5)

Figure 3: The engine main shaft front entry is extended to a horizontal funnel shape and four shaft holder claws (14) to fix it on the 4 channels (17) over the cooling shaft.

Figure 4: Fixing of the external cooling shaft (2) to the 4 claws (14) inside the main shaft (5).

Figure 5: An airtight bearing (4) is fixed to the entry point of the main shaft (5) in order to prevent the air leak from the external cooling fan (1). The internal part of the casing is also suitably fixed inside the inner bracelet of the bearing (4). Figure 6: The air sucked by the cooling fan stages (1) goes through the engine main shaft (5), axially, and goes into the cool air discharge holes (6,7)

Figure 7: The cool air exits the main shaft air duct radially (6,7), goes through the radial passageway (10,11) inside the HPT and LPT disks (8,9), and travels through the air ducts (15,16) of each turbine disk blade (12,13), and blows through the hot gas flow into the turbine, so the cooling is complete. Two airtight bearings (20) are affixed to the outer bracelet (20), and the inner bracelets (20) of the bearings are affixed to the main shaft (5). The LPT disk is also affixed to the cool air passageway (7) on the main shaft (5). This invention is a suitable cooling technique for Turbofan, Turboshaft, Turboprop and Turbojet engines.

In addition, in thisinvention, a better cooling is obtained by dripping water from the stator (18) inside the external cooling fans which is evaporated inside the HPT (8) and LPT (9) disks, and goes through the turbine blades, (not shown). It is considered that a more effective cooling can be obtained by maintaining air tightness on the gap between the external cooling fan (1), HPT (8) and LPT (9) turbine blades.

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SUBSTITUTE SHEETS (RULE 26) The method of applying this invention for industrial use

The technique described above brings a successful solution for the technical problems in the cooling process of conventional Gas Turbine engines with an external cooling technique. This is a product that can be manufactured industrially with a design and manufacturing work that can be carried out just like other gas turbine jet engines, as explained in the Figures.

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