JPH04224204A - Supporting structure of turbine nozzle blade - Google Patents

Abstract

PURPOSE:To obtain a nozzle supporting structure which always keeps constant a contact are for supporting a nozzle blade and prevents excessive stress from being concentrated on the nozzle blade, even if the nozzle blade differs in thermal stretching between an inner cylinder and an outer cylinder exists. CONSTITUTION:A supporting structure of a turbine nozzle blade 1 supports the turbine nozzle blade 1 between an outer cylinder 9 and an inner cylinder 5. The turbine nozzle blade 1 has an inner peripheral wall part and an outer peripheral wall part as well as a blade part. The supporting structure comprises an outer holder 2 having a recess in contact with an anti-gas passage of the outer peripheral wall part of the turbine nozzle blade 1 and an inner holder 3 having a recess in contact with and supporting an anti-gas passage of the inner peripheral wall part of the turbine nozzle blade 1. Further the structure comprises a first heat shielding body 1 placed in the recess of the outer holder 2, a second heat shielding body 7 placed in the recess of the inner holder 3 and second elastic bodies 2a, 2b which are supported under push-pressure between the outer holder 2 and the inner cylinder 5.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

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

0002

2. Description of the Related Art In high-efficiency gas turbines, ceramics are sometimes used for the material of nozzle blades in order to improve their thermal efficiency. In other words, research is being conducted to use brittle materials such as ceramics for nozzle blades in response to the demand for higher turbine inlet temperatures, but in this case, steady and unsteady thermal stress applied to the nozzle blades, thermal expansion difference, etc. The problem is how to minimize the stress exerted on the nozzle blades by the gas force.

[0003] The problem of reducing the thermal stress applied to the hot gas passage portion of the nozzle blade surface and the local stress applied in the radial direction of the blade array was solved by supporting the plate-shaped nozzle blade with a spring-loaded presser bar. 9 and 10 show a support structure for a nozzle blade made of such a ceramic material, FIG. 9 being a sectional view thereof, and FIG. 10 being a sectional view taken along line II in FIG. 9.

[0004] This ceramic nozzle blade 1 is supported by an outer cylinder 9 and an inner cylinder 5 with a heat shield material 15 and a seal material 16 in between. The tangential force in the circumferential direction from the working gas applied to the nozzle blades is applied via the presser bar 12 that fits into the detent grooves 12a on the inner peripheral wall and the outer peripheral wall 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. Note that 18 is a front heat shield, and 20 is a cooling channel. The presser bar 12 is attached to the inner tube 5 and the outer tube 9 via a spring 17, and is capable of absorbing the difference in thermal expansion between the nozzle blade 1 and the inner and outer tubes.

[0005]

[Problem to be Solved by the Invention] 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 difficult to avoid concentration of stress on this portion. In addition, if the inner cylinder 5 and outer cylinder 9 shift in the circumferential and axial directions of the blade row due to differences in thermal expansion, etc., the nozzle blades will tilt and the rear heat shield and presser rod that are in surface contact with the nozzle blades will tilt. The problem still remains that stress is concentrated here because it is a line or point contact.

[0006] In view of these points, the present invention always maintains a constant contact area that supports the nozzle blade even if there is a difference in thermal expansion between the nozzle blade and the inner and outer cylinders, thereby preventing excessive stress from concentrating on the nozzle blade. The purpose of this invention is to obtain a nozzle support structure that does not cause any damage. [Structure of the invention]

[0007]

[Means for Solving the Problems] The present invention provides an internal structure that integrally projects from both ends of a plate-shaped wing section in a direction perpendicular to a plane containing the wing section, and forms a working gas passage section together with the wing section. In a support structure for a turbine nozzle blade that supports a turbine nozzle blade having a peripheral wall portion and an outer peripheral wall portion between an outer cylinder and an inner cylinder, the inner peripheral wall portion of the turbine nozzle blade is supported in contact with an anti-gas passage portion. an inner holder having a recess that supports the outer peripheral wall of the turbine nozzle blade, an outer holder having a recess that contacts and supports the opposite gas passage of the outer peripheral wall of the turbine nozzle blade, a first heat shielding material disposed in the recess of the inner holder, A second heat shielding material disposed in the recessed part of the holder, a first elastic body press-supported between the inner holder and the inner cylinder, and a first elastic body press-supported between the outer holder and the outer cylinder. This is a support structure for a turbine nozzle blade, characterized in that it is provided with a second elastic body.

[0008]

[Operation] By combining the nozzle blades of this structure between the above-mentioned support structures, even if there is a difference in thermal expansion in the height direction of the nozzle blades between the outer cylinder and the inner cylinder, the expansion and contraction effect of the elastic body Do not apply excessive force to the nozzle blades. In addition, even if the nozzle blade is tilted due to displacement due to differences in thermal expansion in the circumferential direction and the axial direction, the gas force exerts a pressing force against the support structure, so the expansion and contraction effect of the spring also causes the support structure to The contact surface with the tilted nozzle blade is maintained and stress concentration can be avoided. Furthermore, by interposing a heat shield material between the nozzle blades and the support structure, even if the nozzle blades are made of ceramic, the temperature of the parts can be made uniform, and excessive thermal stress can be prevented from occurring. .

[0009]

[Embodiment] An embodiment of the present invention will be described below.

FIG. 1 is a perspective view showing the main body of the nozzle blade support structure of the present invention, and FIG. 2 is a perspective view showing one of the turbine nozzle blades 1.
FIG. 3 is an exploded view showing a nozzle blade support structure for a pitch. The nozzle blade 1 is made of a heat-resistant material such as ceramics, and the blade portion 1a has a curved plate shape suitable for changing the flow of gas and increasing its speed. The wing portion 1a is integrally formed with an inner circumferential wall portion 1b and an outer circumferential wall portion 1c that protrude from both inner and outer circumferential ends in a direction orthogonal to a plane including the wing portion 1a, forming one pitch. The wing portion 1a, the inner circumferential wall portion 1b, and the outer circumferential wall portion 1c are connected by smooth curved surfaces, and the wall thickness including the boundary portions is uniform.

This turbine nozzle blade 1 has a first heat shield material 6
It is fitted into the outer holder 2 via the second heat shielding material 7, and fitted into the inner holder 3 via the second heat shielding material 7. The outer holder 2 has first elastic bodies (for example, plate springs) 2a, 2
The inner holder 3 is fitted into the outer cylinder via b, and the inner holder 3 is fitted into contact with the inner cylinder 5 via a second elastic body (for example, a leaf spring) 4.

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

The nozzle blade 1 has a metal outer holder 2 which is a support structure having a concave outer periphery attached to an outer cylinder 9 and an inner cylinder 5.
and a metal inner holder which is an inner circumferential recessed support structure.
The outer circumferential wall 1c and inner circumferential wall 1d are fitted into the respective recesses of No. 3, and are mounted between the outer circumferential side and the inner circumferential side.

Between the outer peripheral side anti-gas passage surface 1e of the nozzle blade 1 and the recessed part of the outer holder 2 and the inner peripheral side anti-gas passage surface 1d
A first heat shielding material 6 and a second heat shielding material 7 are inserted between the recessed portions of the inner holder 3 and 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 the The outer cylinder 1,
The inner cylinder 2 is supported under pressure.

FIG. 5 shows details of portion A in FIG. 4 as an example of the state inside the recess of the recess-shaped support structure. A third heat shield 11 is inserted to protect the gas passage surface and the recessed surface of the metal outer holder 2 which are exposed to high temperatures. Since the shape of the outer peripheral wall 1c of the nozzle blade 1 and the first heat shield 6 is smaller than the recess of the outer holder 2, the outer peripheral wall 1c of the nozzle blade 1 and the first heat shield 6 are smaller than the recess of the outer holder 2. It is possible to move within the recessed portion of No. 2. The same applies to the inner holder 3. Seal plates 10 are inserted into the gaps between adjacent outer holders 2 and between adjacent inner holders 3.

[0017] Accordingly, due to the forces of the first elastic bodies 2a, 2b and the second elastic body 4, the outer circumferential side opposite gas passage portion surface 1e of the nozzle blade 1 is caused to contact the first heat shielding material 6 with the inner circumferential side. The opposite gas passage surface 1d contacts the second heat shielding material 7.

Further, due to the gas force passing through the nozzle blade 1, the outer circumferentially thick end face 1f and the inner circumferentially thick end face 1g of the nozzle wing 1 are moved to the third wall of the recessed inner wall of the outer holder 2. in contact with the heat shield plate 11 of the outer peripheral side axially thick end surface 1
h and the inner peripheral axially thick end face 1i contact the third heat shielding material 11 on the inner wall of the recess of the inner holder 3.

For example, when the nozzle blade 1 is exposed to high temperature gas, the state changes from the normal state of FIG. 6A to FIG. 6B, as shown in FIG.
Assume that thermal elongation (δ1) or the like occurs in the height direction of the nozzle blade 1 as shown in FIG. The nozzle blade 1 pushes the outer holder 2 and the inner holder 3 via the first heat shield 6 and the second heat shield 7. Here, the first elastic bodies 2a and 2b of the outer holder 2 contract and absorb the thermal elongation in the height direction of the nozzle blade 1, and the outer peripheral side anti-gas passage surface 1e of the nozzle blade 1 and the first The contact state of the contact surface of the heat shield material 6 can also be maintained.

Next, thermal expansion occurs in the circumferential direction due to temperature difference between the outer cylinder 9 that holds the outer holder 2 and the inner cylinder 5 that holds the inner holder 3, resulting in a displacement (δ2) as shown in FIG.
Suppose that occurs. Here, since the outer circumferentially thick end surface 1f of the nozzle blade 1 pressurizes the third heat shield material 11 on the inner wall of the recess of the outer holder 2, the third heat shield material 11 of the outer holder 2 has a
Due to the expansion and contraction effect of the elastic bodies 2a and 2b, the nozzle blade 1
The nozzle blade 1 side of the holder 2 can be tilted so as to maintain the contact state between the thick end face 1f of the outer peripheral side in the axial direction and the contact surface of the third heat shielding material 11 on the inner wall of the recess of the holder 2. Moreover, it is possible to maintain contact between the inner circumferential side anti-gas passage surface 1d and the outer circumferential side anti-gas passage surface 1e of the nozzle blade and the contact surfaces of the first heat shield plate 6 and the second heat shield plate 7.

Finally, the outer cylinder 9 that holds the outer holder 2
Thermal elongation occurs in the axial direction due to the temperature difference between the inner cylinder 5 that holds the inner holder 3, and the displacement (δ3) shown in FIG.
) occurs. Here, too, the outer circumferential axis of the nozzle blade 1 is Contact surface between the third heat shielding material 11 between the thick end face 1h in the direction and the inner wall of the recess of the holder 2, and the third heat shield between the thick end face 1i in the axial direction on the inner peripheral side of the nozzle blade 1 and the inner wall of the recess of the holder 2 The inner holder 2 and the outer holder 3 can be tilted so as to maintain contact with the contact surface of the material 11. and,
It is also possible to maintain contact between the inner circumferential side anti-gas passage surface 1d and the outer circumferential side anti-gas passage surface 1e of the nozzle blade 1 and the contact surfaces of the first heat shield plate 6 and the second heat shield plate 7.

As mentioned above, the radius, circumference,
Since the contact surface between the nozzle blade 1 and its support structure is kept constant against displacement occurring in the axial direction, uneven contact can be prevented and excessive stress concentration in the nozzle blade 1 can be prevented. In addition, even if the nozzle blade 1 is made of ceramic, it is constantly and stably in contact with the heat insulating material between the support structures, and the temperature change at this contact area is small, reducing thermal stress at this area. .

[0023]

According to the above invention, the contact surface between the nozzle blade and its support structure is always ensured, so that excessive stress concentration on the nozzle blade can be prevented. In addition, when the highly efficient gas turbine nozzle blade is a ceramic nozzle blade that does not require cooling air, the thermal stress of the nozzle blade in the contact area between the support structure and the support structure is reduced, and a reliable structure can be achieved.

[Brief explanation of the drawing]

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

[Figure 2] Exploded view of nozzle blade support structure

[Figure 3] Front view seen from the gas inflow direction in Figure 1

[Figure 4] Cross-sectional view taken along line H-H in Figure 3

[Figure 5] Detailed view of the A-A section in Figure 4

[Figure 6] Explanatory diagram when the nozzle blade is thermally expanded in the height direction from its normal state

[Figure 7] Explanatory diagram when the nozzle blade is displaced from the axial direction

[
Figure 8: Explanatory diagram when the nozzle blade stretches in the axial direction and causes displacement

[Fig. 9] Cross-sectional view showing a conventional example

[Fig. 10] Cross-sectional view taken along line I-I in Fig. 9

[Explanation of symbols]

Claims (1)

[Claims] Claims: 1. An inner circumferential wall and an outer circumferential wall that integrally protrude from both ends of a plate-shaped wing in a direction perpendicular to a plane containing the wing and constitute a working gas passage together with the wing. In a support structure for a turbine nozzle blade that supports a turbine nozzle blade between an outer cylinder and an inner cylinder, the outer holder has a recessed part that contacts and supports an anti-gas passage part of an outer peripheral wall part of the turbine nozzle blade. an inner holder having a recessed portion that contacts and supports the anti-gas passage portion of the inner circumferential wall portion of the turbine nozzle blade; a first heat shielding material disposed in the recessed portion of the outer holder; a second heat shield disposed in the recess, a first elastic body supported under pressure between the outer holder and the outer cylinder, and a first elastic body supported under pressure between the inner holder and the inner cylinder. A support structure for a turbine nozzle blade, comprising a second elastic body.