RU2534684C1 - Turbine of double-circuit gas turbine engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: turbine of a double-circuit gas turbine engine includes turbines of high and low pressures with supports of turbine rotors. Inside the rotor of the low pressure turbine there is an air cavity of high pressure connected at the inlet to the air cavity of the first nozzle block of the low pressure turbine, and at the outlet via the rear labyrinth seal - with a flow path of the low pressure turbine. The air cavity of high pressure is limited at the inner side - by the first and second labyrinth seals. Seals separate the air cavity of high pressure from the air cavity of low pressure. The air cavity of low pressure is divided into front and rear cavities. The front cavity is arranged between the high pressure turbine support and a cone flange of the low pressure turbine shaft. The rear cavity is located between the cone flange of the low pressure turbine shaft and low pressure turbine support. The first and second labyrinth seals are located relative to each other in such a manner that the ratio of the minimum diameter along sealing combs of the first labyrinth seal to the minimum diameter along sealing combs of the second labyrinth seal makes 1.2…2.0.

EFFECT: invention makes it possible to increase reliability and efficiency of a turbine.

3 dwg

Description

The invention relates to turbines of dual-circuit gas turbine engines for aviation applications.

A known turbine dual-circuit gas turbine engine, in which the rotor of the high pressure turbine and the rotor of the low pressure turbine are mounted on bearings of the inter-turbine bearings (US Patent No. 6883303, 04/26/2005, F02C 7/20).

The disadvantage of this design is its low efficiency due to increased loads from the rotor on the turbine struts, which radially deform the turbine housing.

Closest to the claimed turbine is a double-circuit gas turbine engine, including a rotor support of a high pressure turbine installed at the outlet of the high pressure turbine, and a rotor support of the low pressure turbine installed at the outlet of the low pressure turbine (US Patent No. 7921634, 04/12/2011, F02K 3/02, F02K 3/072).

A disadvantage of the known design adopted for the prototype is the low reliability and efficiency (Efficiency) due to the increased value of the axial gas force acting on the rotor of the low pressure turbine.

The technical result of the claimed invention is to increase the reliability and efficiency of the turbine by providing cooling of the disks of all stages of the rotor, eliminating the ingress of hot air of high pressure into the oil cavities of the bearing supports of high and low pressure turbines, as well as reducing the axial force acting on the rotor of the low pressure turbine.

, где:The specified technical result is achieved by the fact that in the turbine of a double-circuit gas turbine engine, including the support of the rotor of the high pressure turbine installed at the outlet of the high pressure turbine and the support of the rotor of the low pressure turbine installed at the outlet of the low pressure turbine, there is an air high pressure cavity connected at the inlet to the air cavity of the first nozzle apparatus of the low pressure turbine, and at the outlet through the rear labyrinth seal - with the flow part of the low-pressure turbine, while the high-pressure air cavity is made limited on the outer side by the rotor disks of the low-pressure turbine, on the front of the gas flow side - the support of the high-pressure turbine, on the back side - the support of the low-pressure turbine, and on the inside - the first and second labyrinth seals separating the air cavity of high pressure from the air cavity of low pressure, and the air cavity of low pressure is divided into front and rear floor spine, while the front cavity is located between the support of the high pressure turbine and the conical flange of the shaft of the low pressure turbine, and the rear cavity is located between the conical flange of the shaft of the low pressure turbine and the support of the low pressure turbine, the front cavity being connected at the inlet through the first labyrinth seal with the air cavity high pressure, and at the outlet through channels made in the conical flange of the shaft, with the back cavity, which at the inlet through the rear labyrinth seal is connected to the air cavity high pressure, and at the outlet through the channels made in the support of the low pressure turbine - with the atmosphere, while the first and second labyrinth seals are located relative to each other so that the ratio $$\frac{D}{d}=\mathrm{1,2}-2.0$$

where:

D is the minimum diameter along the sealing combs of the first labyrinth seal;

d is the minimum diameter along the sealing combs of the second labyrinth seal.

The execution inside the rotor of a low-pressure turbine of an increased pressure air cavity connected at the inlet with the air cavity of the first nozzle apparatus of the low-pressure turbine, and at the outlet through the rear seal at the outlet of the low-pressure turbine, with the flow part of the low-pressure turbine at its outlet, and limited to the outer side of the rotor discs of the low-pressure turbine, on the front side - the support of the high-pressure turbine, on the back side - the support of the low-pressure turbine, eliminates the high gas to the inside of the rotor of the low pressure turbine, to ensure reliable cooling of the disks of all stages of the rotor, including during transient operation of the turbine, which increases the reliability of the turbine.

The execution inside the air cavity of increased pressure of the air cavity of reduced pressure, separated from the outside from the air cavity of the increased pressure by the first (front) and second (rear) labyrinth seals, from the inside by the shaft of the low pressure turbine and divided into the front cavity of the reduced pressure, limited to the front side of the support of the high pressure turbine, on the back side - the conical flange of the shaft of the low pressure turbine connected to the air through the first labyrinth seal high pressure cavity, and at the outlet, through the channels in the conical flange of the turbine shaft, with the rear low pressure cavity, which is additionally connected at the inlet through the second labyrinth seal to the high pressure air cavity, and at the outlet, through the channels in the low pressure turbine support, with the atmosphere, and which is limited on the front by the tapered shaft flange of the low-pressure turbine, and on the back by the support of the low-pressure turbine, increases the reliability of the turbine due to the exclusion of highly loaded contact th shaft of a low-pressure turbine with high-temperature gas and ensures reliable operation of the bearing bearings of the high-pressure turbine and low-pressure turbine, eliminating the entry of high pressure hot air into these oil cavities of these bearings.

The implementation of the front labyrinth seal, separating the low pressure air cavity from the external high pressure air cavity with a larger diameter relative to the rear labyrinth seal, can significantly reduce the axial force acting on the low pressure turbine rotor from gas forces.

увеличивается осевая сила от газовых сил, действующих на ротор турбины низкого давления; при $$\frac{D}{d}>\mathrm{2,0}$$

ухудшается экономичность турбины из-за увеличения паразитных утечек охлаждающего воздуха из полости повышенного давления через переднее лабиринтное уплотнение в атмосферу.At $$\frac{D}{d}<\mathrm{1,2}$$

axial force increases from gas forces acting on the rotor of a low pressure turbine; at $$\frac{D}{d}>2.0$$

the turbine's efficiency is deteriorating due to an increase in spurious leakage of cooling air from the pressure cavity through the front labyrinth seal to the atmosphere.

Figure 1 shows a longitudinal section of a turbine of a dual-circuit gas turbine engine; figure 2 shows the element I in figure 1 in an enlarged view; figure 3 shows the element II in figure 1 in an enlarged view.

The turbine 1 of the dual-circuit gas turbine engine consists of a high pressure turbine 2 and a low pressure turbine 3. The rotor of the high pressure turbine 2 is mounted on a bearing 4 located in the support 5 of the high pressure turbine 2, which is installed at the outlet 6 of the turbine 2.

The rotor of the low pressure turbine 3 is mounted on a bearing 7 located in the support 8 of the low pressure turbine 3, which is installed at the outlet 9 of the turbine 3. The rotor of the low pressure turbine 3 consists of a plurality of disks 10 connected by conical flanges 11 and 12, and from the blades 13 mounted on each of the disks 10 and from the shaft 14 of the low pressure turbine 3 connected by a conical flange 15 of the shaft 14 to the diaphragm 16 of the disk 17. Each of the disks 10 consists of a hub 18, a web 19 and a rim 20.

Inside the rotor of the low-pressure turbine 3, a cavity 21 of increased air pressure is organized, limited on the outside by the disks 10, on the inside - the first (front) 22 and second (rear) 23 labyrinth seals, on the front side - the support 5 of the high-pressure turbine 2 and with the back side - a support 8 of the low pressure turbine 3 and connected at the inlet to the air cavity 24 nozzle blades 25 of the first nozzle apparatus of the low pressure turbine 3, and at the outlet, through the rear outlet seal 26 located at the outlet 9 of the low turbine 3 pressure - with a flow part 27. The pressure of the cooling air stream 28 entering the air cavity 24 of the blades 25 due to the intermediate stage of the high pressure compressor (not shown) exceeds the pressure of the gas stream 29 at the inlet to the nozzle apparatus.

The first (front) 22 and second (rear) 23 labyrinth seals on the outside define a low pressure air cavity 30, which is bounded on the inside by a shaft 14 of a low pressure turbine 3, on the front side by a support 5 of a high pressure turbine 2, on the back side - the support 8 of the turbine 3 low pressure and is located inside the air cavity 21 high pressure.

The reduced pressure air cavity 30 is divided by a conical flange 15 of the shaft 14, made with holes (channels) 31, into a reduced pressure front air cavity 32 and a reduced pressure rear air cavity 33. The cavity 32 is connected at the inlet through the first (front) labyrinth seal 22 with a pressurized air cavity 21, and at the outlet, through openings 31, with a rear air cavity 33, which is further connected through the second (rear) labyrinth seal 23 with the air cavity 21 high pressure, and at the outlet, through openings (channels) 34 made in the support 8 of the low-pressure turbine 3, 34 with atmosphere 35.

The reduced air pressure in the cavities 33 and 34 eliminates the ingress of high-temperature air into the oil cavities 36 and 37 of the supports 4 and 8 of the turbine 1.

, где:The first (front) labyrinth seal 22 and the second (rear) labyrinth seal 23 are located relative to each other so that the ratio $$\frac{D}{d}=\mathrm{1,2}...2.0$$

where:

D is the minimum diameter along the sealing combs of the first (front) labyrinth seal 22;

d is the minimum diameter of the sealing combs of the second (rear) labyrinth seal 23.

This device works as follows.

When the turbine 1 of the double-circuit gas turbine engine is operating, the cooling air stream 28 passing through the internal air cavity 24 of the nozzle blades 25 is heated by the heat of the gas stream 29 and, further entering the cavity 21, causes the hub 18 and the blade 19 of each of the disks 10 of the rotor 6 to be heated low pressure turbines 3, which reduces the temperature gradient between the rim 20 and the web 19 of each of the disks 10 and increases their cyclic durability. At the same time, due to the heating of the disks 10, the radial clearances between the rotor and the stator of the turbine 3 are reduced, which increases its efficiency.

Claims (1)

A bypass turbine gas turbine engine including a high pressure turbine rotor support mounted at the outlet of the high pressure turbine and a low pressure turbine rotor support mounted at the outlet of the low pressure turbine, characterized in that an increased pressure air cavity is located inside the low pressure turbine rotor, connected at the inlet to the air cavity of the first nozzle apparatus of the low pressure turbine, and at the outlet through the rear labyrinth seal, to the turbine flow part pressure, while the high-pressure air cavity is made limited by the low-pressure turbine rotor disks on the outer side, the high-pressure turbine support on the gas flow side, the low-pressure turbine support on the back side, and the first and second labyrinth on the inside seals separating the air cavity of the increased pressure from the air cavity of the reduced pressure, and the air cavity of the reduced pressure is divided into front and rear cavities, while the front cavity is located between the support of the high pressure turbine and the conical flange of the shaft of the low pressure turbine, and the rear cavity is located between the conical flange of the shaft of the low pressure turbine and the support of the low pressure turbine, the front cavity being connected at the inlet through the first labyrinth seal with a pressurized air cavity, and at the outlet through channels made in the conical flange of the shaft - with the back cavity, which at the inlet through the rear labyrinth seal is connected to the air cavity of high pressure, and at the outlet Without channels made in the support of the low-pressure turbine - with the atmosphere, while the first and second labyrinth seals are located relative to each other so that the ratio $$\frac{D}{d}=\mathrm{1,2}...2.0$$

where:
D is the minimum diameter along the sealing combs of the first labyrinth seal;
d is the minimum diameter along the sealing combs of the second labyrinth seal.

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