JP5464233B2 - Compressor blade - Google Patents

Description

  The present invention relates to a compressor blade, and more particularly to a compressor blade.

  In a gas turbine or a jet engine, a multistage axial flow compressor in which a moving blade row and a stationary blade row are alternately combined is used as a compressor that compresses air taken from outside.

  In a multi-stage axial flow compressor, the radial end (hub side) of the stationary blade constituting the stationary blade row or the radial tip end (tip side) of the moving blade constituting the movable blade row, There is a gap (clearance) between the opposing surfaces, and the leakage flow (clearance flow) flowing through this clearance contributes to a decrease in the performance of the compressor.

  Therefore, Patent Documents 1 and 2 have already been proposed as means for reducing this leakage flow (clearance flow) or its influence.

An object of the shroud-integrated moving blade of Patent Document 1 is to prevent a leakage flow of a gas path.
As shown in FIG. 5, in the shroud-integrated moving blade 60, the shroud 53 is provided from the front edge 61 to the rear edge 62 of the tip of the moving blade 52, and the radius of the seal fin tip 63 and the end of the shroud trailing edge 64 are arranged. The radius is almost the same. In the split ring 65, the radius of the inner peripheral surface 66 is slightly larger than the radius of the seal fin tip 63 and the radius of the shroud trailing edge 64. As a result, the cavity cross-sectional area 69 existing between the outer surface 56 of the shroud 53 and the inner peripheral surface 66 of the split ring 65 and downstream of the seal fins 57 can be reduced. For this reason, the leakage flow 67 that has passed through the void near the throat from the gas path 55 is blocked by the inner peripheral surface 66 of the split ring 65. Thus, even if the winglet type shroud 53 is used, the leakage flow 67 of the gas path 55 is prevented.

The shroud segment of Patent Document 2 aims to simplify the configuration of the aircraft engine and reduce the weight of the aircraft engine by suppressing an increase in the number of parts of the aircraft engine.
As shown in FIG. 6, honeycomb cells 74 and 75 that allow contact with the chip fins 72 and 73 of the turbine blade 71 are integrally provided on the back surface of the back plate 70, and at the rear end of the back plate 70, A jet shield 76 capable of colliding with a jet J of combustion gas leaked from between the honeycomb cells 74 and 75 and the chip fins 72 and 73 is integrally formed.

JP 2002-371802 A JP 2005-30316 A

  FIG. 3 shows a flow field on the stationary blade hub side in the conventional structure. In this figure, (A) and (B) are cases of both-end supported vanes, (C) and (D) are vanes with hub clearance, and (E) is a vane with spindles.

  FIG. 3A is a side view of the both-end supported stationary blade. In this figure, the both-end supported stationary blade 1A has a radially outer end (tip side) fixed to the inner surface of a stationary body such as a casing and a radially inner end (hub side) fixed to the hub shroud 2A. Further, a labyrinth 4 is provided between the hub shroud 2A and the inner rotating body 3, and the space between them is sealed.

  FIG. 3B is a plan view showing a cascade of both-end supported stationary vanes. In this case, since the clearance flow does not occur on the tip side and the hub side of the stationary blade 1A, the low energy fluid 5 accumulates at the negative pressure surface corner portion of each stationary blade 1A. Here, the low energy fluid means a fluid having a low speed and vortex or separation. The presence of such a low energy fluid 5 disturbs the flow on the stationary blade suction surface and lowers the stationary blade performance.

  FIG. 3C is a side view of a stationary blade with a hub clearance. In this figure, a stationary blade 1B with a hub clearance has a radially outer end (tip side) fixed to the inner surface of a stationary body such as a casing, and a radially inner end (hub side) spaced from the inner rotating body 3 with a gap. To position. That is, in the stationary blade 1 </ b> B with the hub clearance, there is a hub side clearance (hub clearance 6 </ b> A) between the rotating body 3.

  FIG. 3D is a plan view showing a cascade of a stationary blade with a hub clearance. In this case, a clearance flow 7 flowing through the hub clearance 6A is generated on the hub side of the stationary blade 1B. Since this clearance flow 7 flows from the pressure surface of the stationary blade 1B to the suction surface, the low energy fluid 5 accumulated in the suction surface corner as shown in FIG. Move to the side. As a result, the low energy fluid 5 accumulates on the pressure surface side of each stationary blade 1B. Due to the presence of the low energy fluid 5, the flow at the stationary blade pressure surface is disturbed, and the stationary blade performance is degraded.

FIG. 3E is a side view of a stationary blade with a spindle. In this figure, the spindle stationary vane 1C has a radially outer end (tip side) fixed to the inner surface of a stationary body such as a casing, and a radially inner end (hub side) fixed to a stationary part via a spindle mechanism 15. Has been. In this spindle-equipped stationary blade 1C, there is a hub-side gap (hub clearance 6B) between the stationary portion, but since the opposed surface is stationary, almost no clearance flow occurs.
For this reason, the plan view showing the cascade of the stationary blades with spindles is the same as FIG. 3B, and the low-energy fluid 5 accumulates at the negative pressure surface corner portion of each stationary blade. The presence of such a low energy fluid 5 disturbs the flow on the stationary blade suction surface and lowers the stationary blade performance.

The problem described above also occurs in the compressor blades.
FIG. 4 shows a flow field on the blade tip side in the conventional structure. In this figure, (A) and (B) are the blades with shrouds, and (C) and (D) are the blades with clearance.
FIG. 4A is a side view of a rotor blade with a shroud. In this figure, the blade 8A with shroud has a radially inner end (hub side) fixed to the inner rotating body 3, and a radially outer end (tip side) fixed to the tip shroud 2B. Further, a labyrinth 4 is provided between the tip shroud 2B and the outer stationary body and seals between them.

  FIG. 4B is a plan view showing a blade row of a moving blade with a shroud. In this case, since no clearance flow occurs on the tip side and the hub side of the moving blade 8A, the low energy fluid 5 accumulates at the negative pressure surface corner portion of each moving blade 8A. Due to the presence of such a low energy fluid, the flow on the blade suction surface is disturbed, and the blade performance is degraded.

  FIG. 4C is a side view of the moving blade with clearance. In this figure, the moving blade 8B with clearance has its radially inner end (hub side) fixed to the inner rotating body 3, and its radially outer end (tip side) is located with a gap from the outer stationary body. . That is, in the moving blade 8B with clearance, there is a tip side gap (tip clearance 6B) between the outer stationary body.

  FIG. 4D is a plan view showing a blade row of a moving blade with a clearance. In this case, a clearance flow 7 flowing through the tip clearance 6B is generated on the tip side of the moving blade 8B. Since this clearance flow 7 flows from the pressure surface of the moving blade 8B to the suction surface, the low energy fluid 5 accumulated in the suction surface corner as shown in FIG. Move to the side. As a result, the low energy fluid 5 accumulates on the pressure surface side of each blade 8B. Due to the presence of the low energy fluid 5, the flow on the blade pressure surface is disturbed, and the performance of the blade 8B deteriorates.

  The present invention has been developed to solve the above-described problems. That is, an object of the present invention is to provide a compressor blade that can reduce the influence of a low-energy fluid generated between blade rows and prevent the blade row performance from being lowered.

According to the present invention, the compressor blades having a radially inner end fixed to the outer surface of the rotating body and a radially outer end positioned close to the inner surface of the stationary body,
Has a sealing mechanism for sealing airtight between the upstream side of the radially outer end a stationary body surface, downstream remainder of the sealing mechanism have a tip clearance between the stationary body surface,
The upstream range sealed by the sealing mechanism is from the leading edge to the maximum blade thickness,
A compressor blade is provided in which the tip clearance is from the maximum blade thickness to the trailing edge .

  According to a preferred embodiment of the present invention, the sealing mechanism is a shroud cavity that is a hollow cylindrical concave groove provided on the inner surface of the stationary body, and is located in the shroud cavity at a certain distance from the inner surface of the stationary body. A hollow cylindrical chip shroud.

  Further, a seal member is provided between the tip shroud and the shroud cavity.

According to the compressor blade of the present invention described above, the clearance between the upstream side of the outer end in the radial direction and the inner surface of the stationary body is hermetically sealed by the sealing mechanism. Since the remaining part has a chip clearance between the inner surface of the stationary body, a clearance flow occurs.
By the clearance flow in the vicinity of the trailing edge (trailing edge: T / E), the low energy fluid accumulated in the corner portion of the suction surface can be blown off in the circumferential direction, and separation in this region can be suppressed.

  Therefore, (1) In order to suppress the clearance flow flowing from the vicinity of the leading edge (leading edge: L / E) and separation at the corner, accumulation of low energy fluid on the chip side is reduced, and high efficiency is expected. (2) Since the low-energy fluid on the tip side is extracted in the shroud cavity, an increase in surge margin can be expected.

Note that the effects of the present invention described above have been confirmed by CFD (computer fluid dynamics) analysis.

It is a block diagram of the compressor stationary blade of related invention. It is a block diagram of the compressor rotor blade of this invention. It is a figure which shows the flow field in the stationary blade hub side in a conventional structure. It is a figure which shows the flow field by the blade tip side in the conventional structure. 2 is a schematic diagram of a shroud-integrated moving blade of Patent Document 1. FIG. 6 is a schematic diagram of a “shroud segment” of Patent Document 2. FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a configuration diagram of a compressor vane according to a related invention. FIG. 1A shows a first embodiment, FIG. 1B shows a second embodiment, and FIG.

  1A and 1B, a compressor vane 10 according to a related invention is a compressor vane having a radially outer end fixed and a radially inner end positioned close to the outer surface of the rotating body 3. .

  The compressor vane 10 of the related invention has a sealing mechanism 12 that hermetically seals between the upstream side of the radially inner end and the outer surface of the rotating body 3, and the downstream side remaining of the sealing mechanism 12 is the rotating body 3. A hub clearance 14 is provided between the outer surface and the outer surface.

The upstream range sealed by the sealing mechanism 12 is from the leading edge (leading edge: L / E) to the maximum blade thickness, and the hub clearance 14 is from the maximum blade thickness to the trailing edge (trailing edge: T / E) is preferred.
Further, the gap of the hub clearance 14 from the outer surface of the rotating body should be constant.
However, the related invention is not limited to this configuration, and the hub clearance 14 may be only in the vicinity of the trailing edge or the gap may be changed as long as the effect can be confirmed by CFD analysis.

  In FIG. 1A, in this example, the seal mechanism 12 includes a hollow cylindrical hub shroud 13a that surrounds the outer surface of the rotating body 3 at a predetermined interval, and a gap between the hub shroud 13a and the outer surface of the rotating body 3. It consists of the sealing member 13b (for example, labyrinth seal) which seals airtightly.

  In FIG. 1B, the seal mechanism 12 is a variable blade spindle mechanism 15 in this example. A spindle mechanism 15 having a known structure can be used.

In FIG. 1C, the alternate long and short dash line 11 indicates the boundary between the seal mechanism 12 and the hub clearance 14. In this figure, the left region of the alternate long and short dash line 11 is the hub wall surface stationary portion 11a, and the right region is the hub wall surface rotating portion 11b.
In the hub wall surface rotating part 11b, the outer surface of the rotating body 3 located at the hub clearance 14 rotates from the pressure surface side of the blade to the suction surface side (from the bottom to the top in this figure).

As schematically shown in FIG. 1C, according to the compressor stationary blade 10 of the related invention described above, the upstream side of the radially inner end and the outer surface of the rotating body are hermetically sealed by the sealing mechanism 12. Therefore, although no clearance flow occurs, the remaining downstream portion of the seal mechanism 12 has a hub clearance 14 between the outer surface of the rotating body 3 and a clearance flow 17 is generated in the vicinity of the rear edge.
By the clearance flow 17 in the vicinity of the trailing edge (trailing edge: T / E), the low energy fluid 5 accumulated in the corner portion of the suction surface can be blown off in the circumferential direction, and separation in this region can be suppressed.

  Therefore, (1) Low energy fluid accumulated on the hub side can be reduced and high efficiency can be expected. (2) Since the static pressure difference from the upstream is small compared to the configuration having a slit downstream of the T / E, the leakage flow The loss caused by the can be reduced.

  2A and 2B are configuration diagrams of the compressor rotor blade of the present invention, in which FIG. 2A shows the first embodiment, FIG. 2B shows the second embodiment, and FIG.

2 (A) and 2 (B), the compressor blade 20 of the present invention has a compressor inner blade whose inner end in the radial direction is fixed to the outer surface of the rotating body 3 and whose outer end in the radial direction is located close to the inner surface of the stationary member. It is.
The compressor rotor blade 20 of the present invention has a seal mechanism 22 that hermetically seals between the upstream side of the radially outer end and the inner surface of the stationary body, and the remaining downstream portion of the seal mechanism 22 is between the inner surface of the stationary body. It has a tip clearance 24.

The upstream side range sealed by the sealing mechanism 22 is from the leading edge (leading edge: L / E) to the maximum blade thickness, and the tip clearance 24 is from the maximum blade thickness to the trailing edge (trailing edge: T / E) is preferred.
Further, the gap between the tip clearance 24 and the inner surface of the stationary body is preferably constant.
However, the present invention is not limited to this configuration, and the tip clearance 24 may be only in the vicinity of the trailing edge or the gap may be changed as long as the effect can be confirmed by CFD analysis.

  2A and 2B, the seal mechanism 22 includes a shroud cavity 9a, which is a hollow cylindrical concave groove provided on the inner surface of the stationary body 9, and a constant distance from the inner surface of the stationary body in the shroud cavity 9a. It consists of a hollow cylindrical tip shroud 23 located at a distance.

  In FIG. 2A, a seal member 23b (for example, a labyrinth seal) is provided between a chip shroud 23 and a shroud cavity 9a.

  In FIG. 2C, the alternate long and short dash line 21 indicates the boundary between the seal mechanism 22 and the tip clearance 24. In this figure, the left side region 21a of the alternate long and short dash line 21 is the upstream side without clearance flow, and the right side region 21b is the downstream side with clearance flow. The compressor blade 20 rotates from the suction surface side to the pressure surface side of the blade.

According to the compressor rotor blade 20 of the present invention described above, since the space between the upstream side at the outer end in the radial direction and the inner surface of the stationary body is hermetically sealed by the seal mechanism 22, no clearance flow occurs, but the seal mechanism Since the remaining downstream portion of 22 has a tip clearance 24 between the inner surface of the stationary body, a clearance flow 27 occurs near the rear edge.
By the clearance flow 27 in the vicinity of the trailing edge (trailing edge: T / E), the low energy fluid accumulated at the corner portion of the suction surface can be blown off in the circumferential direction, and separation in this region can be suppressed.

  Therefore, (1) the clearance flow flowing in from the vicinity of the leading edge (leading edge: L / E) and the separation at the corner portion are suppressed, so the accumulation of the low-energy fluid 5 on the chip side is reduced and the efficiency is increased. (2) Since the low-energy fluid 5 on the tip side is extracted into the shroud cavity, an increase in surge margin can be expected.

  The effects of the present invention described above have been confirmed by CFD analysis.

  Further, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention.

1A Both-end supported vane, 1B vane with hub clearance,
1C stationary vane with spindle,
2A hub shroud, 2B tip shroud,
3 rotating body, 4 labyrinth, 5 low energy fluid,
6A Hub clearance, 6B Tip clearance,
7 Clearance flow, 8A blade with shroud,
8B Clearance blade, 9 stationary body, 9a shroud cavity,
10 compressor vane, 11 boundary, 11a hub wall stationary part,
11b Hub wall rotating part, 12 seal mechanism,
13a hub shroud, 13b seal member,
14 hub clearance, 15 spindle mechanism,
17 Clearance flow,
20 compressor blade, 21 boundary, 21a upstream side, 21b downstream side,
22 sealing mechanism, 23 tip shroud,
24 tip clearance, 27 clearance flow

Claims (3)

A compressor blade having a radially inner end fixed to the outer surface of the rotating body and a radially outer end positioned close to the inner surface of the stationary body,
Has a sealing mechanism for sealing airtight between the upstream side of the radially outer end a stationary body surface, downstream remainder of the sealing mechanism have a tip clearance between the stationary body surface,
The upstream range sealed by the sealing mechanism is from the leading edge to the maximum blade thickness,
The compressor blade according to claim 1, wherein the tip clearance is from a maximum blade thickness portion to a trailing edge .   The sealing mechanism includes a shroud cavity that is a hollow cylindrical concave groove provided on the inner surface of the stationary body, and a hollow cylindrical tip shroud that is located in the shroud cavity at a certain distance from the inner surface of the stationary body. The compressor rotor blade according to claim 1, wherein: The compressor blade according to claim 1, further comprising a sealing member between the tip shroud and the shroud cavity.

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