JP2001193405A - Tip shroud having thinning and turbine facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress leakage of main flow gas from a tip clearance to suppress reduction of a turbine efficiency, in relation to a tip shroud with a thinning and a turbine facility. SOLUTION: A fin 5 is erected in a circumferential direction on an outer peripheral surface of a tip shroud 3 of a gas turbine moving blade 8, and a thinning 4 is erected along all circumference of a blade profile. The height of the thinning 4 is set lower than the height of the fin 5 by 1 to 3 mm so as to prevent contact with a casing of a stationary part due to rotation of the moving blade 8. In the conventional art, since there is no thinning 4, flow of gas flowing to the downstream stationary blade side avoiding the fin 5 from the outer peripheral surface of the tip shroud 3 is prevented and reduction of the turbine efficiency is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip shroud with a thinning and a turbine facility, wherein a thinning is provided on an upper surface of a tip shroud of a gas turbine blade to reduce a clearance loss of a turbine, and further employs the tip shroud with a thinning. By doing so, the flow of the main gas stream is made smooth to suppress a decrease in the efficiency of the turbine equipment.

[0002]

2. Description of the Related Art FIG. 3 is a general partial sectional view showing gas turbine equipment. In the figure, combustion takes place in a combustion chamber 10,
The mainstream gas 2 exposed to the high temperature flows into the gas flow path. A plurality of stationary blades 9 are attached to the gas flow path in the direction in which the mainstream gas 2 flows, and a plurality of stationary blades 9 are uniformly arranged on the entire circumference in each stage. The stationary blade 9 is located on the inner peripheral side of the casing 1 that covers the outer peripheral side of the gas flow path, and changes the flow direction of the mainstream gas 2 to a direction in which the operation efficiency of the gas turbine is improved, and accelerates the flow of the mainstream gas 2. I do.

On the downstream side of each stationary blade 9, a moving blade 8 is provided corresponding to the stationary blade 9. The moving blades 8 are planted at equal pitches on the outer periphery in the circumferential direction of the disk 7, and are arranged so as to rotate together with the disk 7 in a space surrounded by the casing 1 and the stationary blade 9. The moving blade 8 is operated by the mainstream gas 2 to output the driving force generated via the disk 7 to the outside to drive a generator and the like. In the illustrated example, the moving blade 8 and the stationary blade 9 show a gas turbine having four stages.

FIGS. 4A and 4B show a conventional wing-cut type chip shroud blade used in the gas turbine equipment shown in FIG. 3, wherein FIG. 4A is a plan view, and FIG. In the figure, reference numeral 3 denotes a chip shroud, and reference numeral 5 denotes a fin. On the outer peripheral surface of the chip shroud 3 of the moving blade 8, one or two (one in the figure) fins 5 are provided upright in the circumferential direction. . The fin 5 allows the mainstream gas 2 to pass through a gap necessarily formed between the blade tip of the rotor blade 8 of the rotating gas turbine (the outer peripheral surface of the tip shroud 3) and the casing 1 as a stationary member. This is provided to prevent leakage flow and a decrease in turbine efficiency.

However, in this conventional structure, FIG.
As shown by reference numeral 6 in (a), the leakage flow from the outer peripheral surface of the chip shroud 3 avoiding the fins 5 is allowed, and the reduction in turbine efficiency cannot be denied.

FIG. 5 is a partial sectional view showing the vicinity of a moving blade in the conventional gas turbine equipment. A cavity 11 is provided inside the casing 1 for storing the moving blade 8 on the upstream side of the moving blade 8.
Exists. Due to the generation of a vortex caused by the rise of the flow in the cavity 11, a flow stagnation region such as a dead water region is generated. Part of the low-energy fluid 12 in this stagnation region is accompanied by the mainstream gas 2 and becomes a leakage flow from the chip clearance above the fins 5, causing the blade 8 to move.
On the inner surface of the casing 1 behind, causing pressure loss. On the other hand, the mainstream gas 2 accompanied by the low-energy fluid 12 flows from the outer peripheral surface of the tip shroud 3 to the downstream stationary vanes 9 avoiding the fins 5, but at this time, the flow is disturbed and the mainstream original inflow is added. Since the gas flows at an angle deviating from the angle, energy loss occurs here as well.

[0007]

As described above, in the conventional chip shroud of the gas turbine rotor blade, the fins 5 are provided on the outer peripheral surface of the chip shroud 3, and the leakage of the mainstream gas from between the casing 1 and the shroud 3 is prevented. Although the decrease in turbine efficiency is suppressed by reducing the number of fins,
In addition, there is a gas flow that leaks out of the fin 5, and a low-energy flow 12 in a stagnation region in the cavity 11 inside the casing 1 flows out of the chip clearance on the upper surface of the fin 5 along with the mainstream gas, and these flows lose pressure And causes a decrease in turbine efficiency.

Accordingly, the present invention provides a thinned tip shroud for a gas turbine rotor blade capable of reducing the clearance loss of the turbine, and provides a turbine facility which employs the thinned tip shroud to improve aerodynamic performance. It is intended to suppress a decrease in turbine efficiency.

[0009]

The present invention provides the following means (1) to (3) in order to solve the above-mentioned problems.

(1) In a blade tip shroud of a gas turbine having fins provided for suppressing a leakage flow of a mainstream gas from a chip clearance with an inner wall of a casing, an outer peripheral surface of the blade shroud follows a profile of the blade. Characterized in that a thinning surrounded by the fins is erected and the height of the thinning is made lower by 1 to 3 mm than the fins.

(2) A turbine facility comprising the tip shroud with thinning according to (1).

(3) In a gas turbine facility having an inner wall of a casing provided to surround a moving blade and a stationary blade, the shape of the inner wall ranges from above the moving blade to near an adjacent stationary blade on the upstream side. A linearly and smoothly extended shape, and the outer periphery of the tip shroud is surrounded by the profile of the rotor blade, and a thinning whose height is 1-3 mm lower than the fins is erected. Characteristic turbine equipment.

In the invention of the above (1), since the thinning surrounds the entire circumference along the profile of the moving blade on the outer peripheral surface of the shroud, the fin is avoided on the outer peripheral surface, and both ends of the fin are avoided. Leakage of the mainstream gas, which tends to flow further downstream, is prevented, and leakage flow from the clearance formed by the fins and casing of the tip shroud can be reduced, resulting in a reduction in turbine efficiency. Becomes Further, in (2) of the present invention, the turbine equipment employs the tip shroud with thinning, and the efficiency of the turbine equipment is improved.

In (3) of the present invention, the inner wall shape of the casing is linearly and smoothly extended from above the moving blades to the vicinity of the upstream stationary blade, so that the cross-sectional area of the flow of the mainstream gas can be improved. Increases, it becomes possible to reduce the inflow speed of the mainstream gas into the moving blade, and the acceleration of the mainstream gas 2 passing through the moving blade is enhanced. This eliminates stagnation in the mainstream gas flow and contributes to an improvement in turbine efficiency. In addition, by eliminating the flow stagnation region, the turbulence of the mainstream gas can be reduced as much as possible, and the loss in the casing or stationary blade arrangement region behind the rotor blades is reduced, and the reduction in turbine efficiency is suppressed. Becomes possible. Further, since the thinning is provided upright, leakage of the mainstream gas which tends to flow from both ends of the fin to the downstream side is prevented by avoiding the fin on the outer peripheral surface, similarly to the invention of the above (1). Leakage flow from a clearance formed by the shroud fins and the casing can be reduced, and a reduction in turbine efficiency can be suppressed by these actions.

[0015]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1A and 1B show a tip shroud with thinning according to a first embodiment of the present invention, wherein FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view along AA in FIG. In the figure, fins 5 are provided upright on the outer peripheral surface of the chip shroud 3 in the circumferential direction. As described in the conventional example, the fins 5 are provided on the rotating blades 8 of the rotating gas turbine.
The gap formed between the blade tip (outer peripheral surface of the tip shroud 3) and the casing 1 as a stationary member
Is provided in order to suppress the leakage flow through which the turbine efficiency decreases.

4 is a thinning, and a chip shroud 3
Of the rotor blade 8 at a constant height along the cross-sectional profile of the rotor blade 8 on the outer peripheral surface of the rotor blade 8. As shown in (b), the height of the thinning 4 is set to be 1 to 3 mm lower than the height of the fins 5 so as to avoid direct contact with the casing 1 which is a stationary member during rotation of the moving blade 8. I have to.

According to the first embodiment of the above construction, the thinning 4 surrounds the entire periphery along the profile of the moving blade 8 and stands upright on the outer peripheral surface of the tip shroud 3.
As shown in FIG. 4 of the conventional example, the mainstream gas flow 6 that escapes from both sides of the outer peripheral surface of the chip shroud 3 while avoiding the fins 5 is obstructed by the thinning 4 and hardly flows. Leakage of the mainstream gas from the clearance between the casing 1 and the casing 1 can be reduced as much as possible, and as a result, a decrease in turbine efficiency can be suppressed.

FIG. 2 is a longitudinal sectional view of a main part of a gas turbine facility using a tip shroud with thinning according to a second embodiment of the present invention. In the figure, as shown in FIG. 1, a thinning 4 is provided upright on the outer peripheral surface of the tip shroud 4 along the profile of the moving blade 8, and the thinning 4 is higher than the height of the fin 5 by 1 as shown in FIG. It is set to be lower by about 3 mm so as to avoid direct contact with the casing 1 which is a stationary member during rotation of the moving blade 8.

Reference numerals 1a and 1b denote casings, which surround the moving blades 8 and the stationary blades 9 to form inner walls. In the casing inner wall shape, the casing 1b on the upstream side of the rotor blade 8
A part of the inner wall portion is removed from the top of the moving blade 8 to the vicinity of the upstream stationary blade 9 as shown in FIG. The space between them is a straight and smoothly extended inner wall shape.

According to the second embodiment of the above construction, the inner wall shape of the casing 1b is conventionally a straight inner wall shape extending from above the moving blade 8 to near the upstream stationary blade 9 smoothly. By eliminating the existing cavity 11,
The cross-sectional area in which the mainstream gas 2 flows increases. This makes it possible to reduce the flow rate of the mainstream gas 2 into the bucket 8. As a result, the mainstream gas 2 passing through the rotor 8
Accelerates the flow, eliminating the stagnation of the flow and contributing to the improvement of the turbine efficiency.

Further, by eliminating the stagnation region of the flow, the turbulence of the mainstream gas 2 can be reduced as much as possible. It is possible to suppress a decrease in efficiency. Further, the fins 5 are formed similarly to the first embodiment.
The mainstream gas flow that leaks from both sides of the outer peripheral surface of the tip shroud 3 and avoids the flow is obstructed by the thinning 4 to make it difficult to flow, and the mainstream gas leaks from the clearance between the fin 5 and the casing 1. Can be reduced as much as possible, and as a result, a decrease in turbine efficiency can be suppressed.

[0022]

According to the present invention, there is provided a tip shroud with a thinning according to the present invention, wherein (1) a moving blade tip shroud of a gas turbine having fins provided for suppressing a leakage flow of a mainstream gas from a tip clearance with an inner wall of a casing. A thinning surrounded on the outer peripheral surface along the profile of the rotor blade is provided upright, and the height of the thinning is made 1 to 3 mm lower than the fin. With this configuration, leakage of the mainstream gas, which avoids the fins on the outer peripheral surface and tends to flow downstream from both ends of the fins, is prevented, and the leakage flow from the clearance formed between the fins and the casing of the chip shroud. Can be reduced, and as a result, a decrease in turbine efficiency can be suppressed. Further, in (2) of the present invention, the turbine equipment employs the tip shroud with thinning, and the efficiency of the turbine equipment is improved.

According to a third aspect of the present invention, there is provided a gas turbine equipment having a casing having an inner wall surrounding a moving blade and a stationary blade. In the gas turbine equipment, the shape of the inner wall is upstream from the moving blade. Of the tip shroud along the profile of the rotor blade and the height of the tip shroud from the fin to 1 mm. The feature is that the thinning which is lowered by ~ 3mm is erected. With such a configuration, the flow rate of the mainstream gas into the moving blade can be reduced, and the acceleration of the mainstream gas 2 passing through the moving blade is enhanced. This eliminates stagnation in the flow of the mainstream gas flow and contributes to an improvement in turbine efficiency. In addition, by eliminating the flow stagnation region, the turbulence of the mainstream gas can be reduced as much as possible, and the loss in the casing or stationary blade arrangement region behind the rotor blades is reduced, and the reduction in turbine efficiency is suppressed. Becomes possible. Further, since the thinning is provided upright, the flow is obstructed by the thinning 4 to make it difficult to flow similarly to the invention of the above (1), and leakage of the mainstream gas from the clearance between the fin 5 and the casing 1 is reduced as much as possible. As a result, it is possible to suppress a decrease in turbine efficiency.

[Brief description of the drawings]

1 shows a tip shroud with thinning according to a first embodiment of the present invention, wherein (a) is a plan view and (b) is (a).
It is AA sectional drawing in.

FIG. 2 is a longitudinal sectional view of a main part of a turbine facility using a tip shroud with thinning according to a second embodiment of the present invention.

FIG. 3 is a general partial longitudinal sectional view of a gas turbine.

4A and 4B show a conventional chip shroud, where FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along line BB in FIG.

FIG. 5 is a longitudinal sectional view of a main part of a conventional gas turbine facility.

[Explanation of symbols]

 1, 1a, 1b Casing 2 Main gas 3 Chip shroud 4 Thinning 5 Fin 8 Moving blade 9 Stationary blade

Claims (3)

[Claims] 1. A gas turbine blade shroud having fins provided to suppress a leakage flow of a mainstream gas from a chip clearance with an inner wall of a casing. A shroud with a thinning, wherein a surrounding thinning is erected, and the height of the thinning is made lower by 1 to 3 mm than the fin. 2. A turbine facility comprising the tip shroud with thinning according to claim 1. 3. A gas turbine facility having an inner wall of a casing provided surrounding a moving blade and a stationary blade, wherein the inner wall shape has a range from above the moving blade to near the adjacent stationary blade on the upstream side. The tip shroud has a linearly and smoothly extended shape, and is surrounded on the outer peripheral surface of the tip shroud along the profile of the rotor blade, and the height of the tip shroud is higher than that of the fin.
Turbine equipment characterized by standing up to 3 mm lower thinning.