JP2609763B2 - Turbine nozzle blade support structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine nozzle blade support structure for supporting a gas turbine nozzle blade.

[0002]

2. Description of the Related Art In a high-efficiency gas turbine, ceramic is sometimes used as a material for nozzle blades in order to improve its thermal efficiency. In other words, studies have been made to use brittle materials such as ceramics for the nozzle blades in response to the demand for increasing the turbine inlet temperature. In this case, steady and unsteady thermal stresses on the nozzle blades, thermal expansion differences, etc. The problem is how to reduce the stress applied to the nozzle blade by the gas force and the gas force.

Here, the reduction of the thermal stress applied to the high-temperature gas passage portion of the nozzle blade surface and the local stress applied in the blade row radial direction has been solved by supporting the plate-shaped nozzle blade with a spring-loaded holding rod. 9 and 10 show such a support structure for a nozzle blade made of a ceramic material. FIG. 9 is a cross-sectional view thereof, and FIG. 10 is a cross-sectional view taken along line II of FIG.

The ceramic nozzle blade 1 is supported by an outer cylinder 9 and an inner cylinder 5 via a heat shield 15 and a seal 16. Then, the circumferential tangential force from the working gas applied to the nozzle blades is applied via the presser rods 12 fitted to the detent grooves 12a of the inner peripheral wall portion and the outer peripheral wall portion of the nozzle blade 1.
The axial force from the working gas is received by the inner cylinder 5 and the outer cylinder 9 via the rear heat shield 19. Reference numeral 18 denotes a front heat shield, and reference numeral 20 denotes a cooling channel. The holding rod 12 is attached to the inner cylinder 5, the outer cylinder 9 and the spring 17 via a spring 17 so as to absorb a difference in thermal expansion between the nozzle blade 1 and the inner and outer cylinders.

[0005]

However, since such a conventional device has a structure in which the circumferential tangential force from the working gas is received by the detent groove 12a, it is inevitable to concentrate the stress applied to this portion. In addition, when the inner cylinder 5 and the outer cylinder 9 are displaced in the circumferential direction and the axial direction of the cascade due to a difference in thermal expansion or the like, the nozzle blades are inclined, and the rear heat shield and the presser bar are in contact with the nozzle blades. The problem remains that stress concentrates here because of the line or point contact.

In view of the above, the present invention keeps the contact area supporting the nozzle blade constant even if a thermal expansion difference or the like occurs between the nozzle blade and the inner and outer cylinders. It is an object of the present invention to obtain a nozzle support structure that does not cause any trouble. [Configuration of the Invention]

[0007]

According to the present invention, there is provided an internal combustion engine comprising a plate-like wing which is integrally protruded from both ends of the wing in a direction perpendicular to a surface including the wing to constitute a working gas passage together with the wing. In a turbine nozzle blade support structure for supporting a turbine nozzle blade having a peripheral wall portion and an outer peripheral wall portion between an outer cylinder and an inner cylinder, the turbine nozzle blade has a gas passage portion on an inner peripheral wall portion of the turbine nozzle blade in contact with the turbine nozzle blade. An inner holder having a concave portion to be formed, an outer holder having a concave portion for contacting and supporting an anti-gas passage portion of an outer peripheral wall portion of the turbine nozzle blade, a first heat shield material disposed in the concave portion of the inner holder, A second heat shield disposed in the recess of the holder, a first elastic body pressed and supported between the inner holder and the inner cylinder, and a second elastic body pressed and supported between the outer holder and the outer cylinder. Turbi characterized by comprising two elastic bodies A support structure of the nozzle blade.

[0008]

By assembling the nozzle blade of this structure between the above-mentioned supporting structures, even if a difference in thermal expansion in the height direction of the nozzle blade occurs between the outer cylinder and the inner cylinder, the elastic body expands and contracts. No excessive force is applied to the nozzle wings. In addition, even if the nozzle blade is tilted due to a displacement such as a difference in thermal expansion between the circumferential direction and the axial direction, a pressing force is applied to the supporting structure by the gas force. The contact surface with the inclined nozzle blade is kept, so that concentration of stress can be avoided. Furthermore, by interposing a heat shield between the nozzle blade and the support structure, even when the nozzle blade is made of ceramic, the temperature of the member is made uniform and excessive thermal stress can be prevented. .

[0009]

An embodiment of the present invention will be described below.

FIG. 1 is a perspective view showing a main body of the nozzle blade supporting structure of the present invention, and FIG.
FIG. 3 is an exploded view showing a nozzle blade support structure for a pitch. The nozzle blade 1 is formed of a heat-resistant material such as ceramics, and the blade portion 1a has a curved plate shape suitable for changing the gas flow and increasing the speed. The wing portion 1a is integrally formed with the inner peripheral wall portion 1b and the outer peripheral wall portion 1c which protrude from both ends on the inner peripheral side and the outer peripheral side in a direction perpendicular to the plane including the wing portion 1a, and constitute one pitch. The wing portion 1a is connected to the inner peripheral wall portion 1b and the outer peripheral wall portion 1c by smooth curved surfaces, and has a uniform thickness including the boundary.

The turbine nozzle blade 1 is provided with a first heat shield 6
And is fitted to the inner holder 3 via the second heat shield 7. The outer holder 2 includes first elastic members (for example, leaf springs) 2a, 2
b, the inner holder 3 is fitted into the outer cylinder via a second elastic body (for example, a leaf spring) 4 so as to be in contact with the inner cylinder 5.

FIG. 3 is an explanatory view of a support structure for supporting the turbine nozzle blades 1 for two pitches adjacent to a plurality of turbine nozzle blades 1 constituting an annular cascade. FIG. 3A
FIG. 3B is a plan view seen from the outer peripheral direction, and FIG. 3B is a front view seen from the gas inflow direction. FIG. 4 is a sectional view taken along line HH in FIG.

The nozzle blade 1 is a metal outer holder-2 which is a support structure having an outer peripheral concave shape mounted on the outer cylinder 9 and the inner cylinder 5.
And a metal inner holder which is an inner peripheral concave support structure
The outer peripheral wall portion 1c and the inner peripheral wall portion 1d are fitted into the respective recesses of No. 3 and are attached so as to be sandwiched from the outer peripheral side and the inner peripheral side.

Between the outer gas passage surface 1e of the nozzle blade 1 and the recessed portion of the outer holder 2 and the inner gas passage surface 1d.
A first heat shield 6 and a second heat shield 7 are interposed between the first and second recesses of the inner holder 3, respectively.

The nozzle blade 1, the first heat shield plate 6, the second heat shield material 7, the outer holder 2 and the inner holder 3 are not fixed to each other, but are embedded in the outer holder 2. Due to the spring force of the second elastic body 4 inserted between the first elastic bodies 2a, 2b and the inner cylinder 5 with the inner holder 3, the outer cylinder 1,
The inner cylinder 2 is pressed and supported.

FIG. 5 shows the details of the portion A in FIG. 4 as an example of the state inside the hollow portion of the hollow support structure. A third heat shield 11 is interposed for protection of the gas passage surface and the depression surface of the metal outer holder 2 exposed to high temperatures. Since the outer peripheral wall portion 1c of the nozzle blade 1 and the shape of the first heat shield 6 are smaller than the recessed portion of the outer holder 2, the outer peripheral wall portion 1c of the nozzle blade 1 and the first heat shield plate 6 are formed of the outer holder. It is possible to move inside the second depression. The same applies to the inner holder-3. A seal plate 10 is inserted into the gap between the adjacent outer holders 2 and the gap between the inner holders 3.

Thus, the outer gas-passing surface 1e of the nozzle blade 1 on the outer peripheral side is brought into contact with the first heat shield 6 by the force of the first elastic bodies 2a, 2b and the second elastic body 4. The anti-gas passage surface 1d contacts the second heat shield 7.

Further, due to the gas force passing through the nozzle blade 1, the outer circumferential side thick end face 1f and the inner circumferential thick end face 1g of the nozzle blade 1 become the third inner wall of the hollow inner wall of the outer holder-2. Contact with the heat shield plate 11 and the outer peripheral side axially thick end face 1
h and the inner peripheral side axially thick end face 1i are in contact with the third heat shield 11 on the inner wall of the recess of the inner holder-3.

For example, when the nozzle blade 1 is exposed to a high-temperature gas, as shown in FIG. 6, the normal state shown in FIG.
Suppose that thermal expansion (δ ₁ ) or the like occurs in the height direction of the nozzle blade 1 as shown in FIG. The nozzle blade 1 has a first heat shield 6 and a second heat shield 6.
Outer holder-2 and inner holder-
You will press 3. Here, the first elastic bodies 2a and 2b of the outer holder 2 contract and absorb the thermal expansion in the height direction of the nozzle blade 1, and the outer-side anti-gas passage surface 1e of the nozzle blade 1 and the first elastic body 2a and 2b. The contact state of the contact surface of the heat shield 6 can also be maintained.

Next, thermal expansion occurs in the circumferential direction due to a temperature difference between the outer cylinder 9 holding the outer holder 2 and the inner cylinder 5 holding the inner holder 3, and the displacement (δ ₂₎ shown in FIG. ) Occurs. Here, since the outer circumferential side thick end face 1f of the nozzle blade 1 presses the third heat shield 11 on the inner wall of the recess of the outer holder-2, the first elasticity of the outer holder-2 is provided. Due to the effect of the expansion and contraction of the bodies 2a and 2b, the holder is held so as to maintain the contact state between the outer circumferential side thick end face 1f of the nozzle blade 1 and the contact surface of the third heat shield 11 on the hollow inner wall of the holder-2. The two nozzle blades 1 can tilt. In addition, the inner peripheral side anti-gas passage surface 1d of the nozzle blade and the outer peripheral side opposite gas passage surface 1
The contact state of the contact surfaces of the first heat shield plate 6 and the second heat shield plate 7 can be maintained.

Finally, the outer cylinder 9 holding the outer holder-2
Thermal expansion occurs in the axial direction due to a temperature difference or the like between the inner cylinder 5 holding the inner holder 3 and the displacement (δ ₃ ) shown in FIG.
Is generated. Again, the first of the outer holder-2 has
Due to the effect of expansion and contraction of the elastic bodies 2a and 2b and the second elastic body 4 between the inner holder 3 and the inner cylinder 5, the outer peripheral side axially thick end face 1h of the nozzle blade 1 and the concave inner wall of the holder 2 So that the contact surface of the third heat shield 11 and the inner peripheral axially thick end face 1i of the nozzle blade 1 and the contact surface of the third heat shield 11 of the hollow inner wall of the holder 2 are maintained. The inner holder 2 and the outer holder-3 can be inclined. In addition, the contact state between the inner and outer gas passage surfaces 1d and 1e of the nozzle blade 1 and the first heat shield plate 6 and the second heat shield plate 7 can be maintained.

As described above, the radius, circumference,
Since the contact surface between the nozzle blade 1 and the supporting structure thereof is kept constant with respect to the displacement occurring in the axial direction, one-side contact can be prevented, and excessive stress concentration does not occur in the nozzle blade 1. Further, even when the nozzle blade 1 is made of ceramic, it is constantly and stably in contact with the heat insulating material between the supporting structures, and the temperature change at the main contact portion is small and the thermal stress at the main portion can be reduced. .

[0023]

According to the present invention, a contact surface between the nozzle blade and its supporting structure is always secured, so that excessive stress concentration at the nozzle blade can be prevented. In the case of a highly efficient gas turbine nozzle blade, especially a ceramic nozzle blade that does not require cooling air, the thermal stress between the supporting structures and the nozzle blade at the contact portion is reduced, and a reliable structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a nozzle blade support structure of the present invention.

FIG. 2 is an exploded view of a nozzle blade support structure.

FIG. 3 is a front view as viewed from a gas inflow direction in FIG. 1;

FIG. 4 is a sectional view taken along line HH of FIG. 3;

FIG. 5 is a detailed view of a portion AA in FIG. 4;

FIG. 6 is an explanatory diagram in the case where the nozzle blades thermally expand in a height direction from a normal state.

FIG. 7 is an explanatory diagram when the nozzle blade is displaced from the axial direction.

FIG. 8 is an explanatory diagram in a case where the nozzle blades extend in the axial direction and cause displacement.

FIG. 9 is a sectional view showing a conventional example.

FIG. 10 is a sectional view taken along line II of FIG. 9;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nozzle blade, 2 ... Outer holder 2a, 2b ... 1st
Elastic body 3 ... Inner holder 4 ... Second elastic body 5 ...
Inner cylinder, 6: first heat shield 7: second heat shield 9: outer cylinder

Claims (1)

(57) [Claims] An inner peripheral wall and an outer peripheral wall which are integrally protruded from both ends of a plate-shaped wing in a direction perpendicular to a surface including the wing and constitute a working gas passage together with the wing. A turbine nozzle blade supporting structure for supporting a turbine nozzle blade between an outer cylinder and an inner cylinder, the outer holder having a recess for contacting and supporting an anti-gas passage on an outer peripheral wall of the turbine nozzle blade. An inner holder having a concave portion that is in contact with and supports an anti-gas passage portion of an inner peripheral wall portion of the turbine nozzle blade; a first heat shield material disposed in the concave portion of the outer holder; A second heat shield disposed in the recess, a first elastic body pressed and supported between the outer holder and the outer cylinder, and a first elastic body pressed and supported between the inner holder and the inner cylinder; And a second elastic body. Support structure of the turbine nozzle blade.