JPH0439394Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement of a ceramic scroll for a gas turbine.

[Prior Art] Generally, in a gas turbine equipped with a combustor that protrudes in a substantially radial direction, combustion gas from the combustor is guided to the turbine by swirling it within a scroll. Therefore, the inner wall of the scroll is exposed to high temperature fuel gas. Therefore, there are scrolls made of ceramic to improve heat resistance (for example, THE AMERICAN SOCIETY OF
(See MECHANICAL ENGINEERS, June 1986 conference presentation).

[Problems to be solved by the invention] By the way, since the scroll is exposed to high-temperature combustion gas, the temperature changes rapidly when the combustor ignites or changes in load, and furthermore, the scroll has a connection part with the combustor and turbine. Therefore, the temperature distribution is highly uneven and the shape is extremely complicated. Metal scrolls can be thin, have high elasticity, and have high thermal conductivity, so they do not generate large thermal stress, whereas ceramic scrolls have thick walls and low elasticity. Moreover, since the thermal conductivity is low, large stress is generated in the scroll mainly due to circumferential thermal stress and stress concentration accompanying this thermal stress. Especially on large scrolls,
There is a risk of damage.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to reduce the thermal stress generated in the ceramic scroll.

[Means for Solving the Problems] In order to achieve the above object, the ceramic scroll of this invention first includes an outer cylinder that forms the radially outer part thereof and is connected to the discharge end of the combustor; It is divided into an inner cylinder which is connected to the outer cylinder and forms a radially inner part. Further, the outer cylinder is composed of divided bodies divided in a complicated manner in the circumferential direction, and each divided body has an overlap margin that covers a gap between the divided ends in the circumferential direction.

[Function] According to this invention, since the ceramic scroll is divided into an inner cylinder and an outer cylinder, thermal stress due to sudden temperature changes is less likely to occur. Moreover, the outer cylinder connected to the combustor is more complex and larger than the inner cylinder, but because it is divided in the circumferential direction,
Since the divided bodies do not restrain each other in the circumferential direction, thermal stress in the circumferential direction is less likely to occur.

Further, since the gap between the divided ends of each divided body is covered by the overlapping margin of the divided bodies, combustion gas can be prevented from leaking from this gap.

[Example] An example of this invention will be described below with reference to the drawings.

In FIG. 1, 1 is a centrifugal compressor, 2 is a radial flow type diffuser, and 3 is a combustor. 4 is an outer housing, and a passage 21 is formed between the outer housing and the inner housing 20.
The inner housing 20 forms an air passage 7 between itself and the inner scroll 6, and the compressed air C from the diffuser 2 is supplied to a heat exchanger (not shown) through the passage 21. The inner housing 20 forms an air passage 7 between itself and the inner scroll 6, and guides the preheated air H that has been heat exchanged to the combustor 3. The scroll 6 guides the combustion gas G from the combustor 3 to the turbine 5, and is housed in the inner housing 20.

The scroll 6 is made of ceramic, and includes an outer cylinder 8 forming a radially outer portion of the scroll 6;
It is divided into an inner cylinder 9 which is connected to the outer cylinder 8 and forms a radially inner part. Therefore, the outer cylinder 8
The outer peripheral surface 8a of is in contact with the air passage 7.

As shown in FIG. 2, the outer cylinder 8 is further divided into, for example, four parts in the circumferential direction, and is composed of a first divided body 81 and three second divided bodies 82. The first divided body 81 is integrally formed with an introduction pipe part 81a that communicates with the combustor inner cylinder 3a, and an introduction end part 81b of the introduction pipe part 81a is connected to a discharge end of the combustor inner cylinder 3a. 3b is fitted and connected.

Overlap allowances 81c and 82c are integrally formed at the circumferential division end portions of each of the division bodies 81 and 82, and a minute gap S generated between each of the division bodies 81 and 82 corresponds to the overlapping allowance 81c and 82c, respectively. 82c. The outer cylinder 8 has the overlapping allowances 81c and 82.
Since c is in contact with the outer periphery of the divided bodies 81 and 82, the shape is prevented from deforming inward, and the shape is maintained in an annular shape.

The overlapping allowances 81c and 82c are formed in the center of the outer cylinder 8 in the axial direction A excluding both ends 8b, as shown in FIG. In addition, each of the divided bodies 81,
Flange portions 81d and 82d that protrude in the outer circumferential direction are integrally formed at the left end portion of 82 in the axial direction A.

On the other hand, in this embodiment, the inner cylinder 9 shown in FIG. 1 is divided into two parts in the axial direction A, and the first inner cylinder 9
1 and a second inner cylinder 92. In the first inner cylinder 91, a small annular portion 91a and a deflector portion 91b are integrally formed via a stay 91c, and a passage 11 for introducing combustion gas G into the first stage ceramic stator blade 10 is formed. is formed. Note that a seal ring 12 is provided at the inner diameter end of the deflector portion 91b.

The second inner cylinder 92 is formed into a tapered cylindrical shape, and is in contact with the small annular portion 91a and the outer cylinder 8. The second inner cylinder 92 and the outer cylinder 8 are in contact with each other at the spigot joint 92a to prevent leakage of the combustion gas G, and the spigot joint 92a is connected to the outer periphery of the outer cylinder 8. The fittings help prevent the outer tube 8 from deforming in the outer diameter direction.

The outer peripheral end portion 93 of the deflector portion 91b is
As clearly shown in FIG. 4, it is in contact with the flanges 81d and 82d of the scroll outer cylinder 8. The outer peripheral end 93 of the deflector portion 91b and the flanges 81d and 82d of the scroll outer cylinder 8 are connected to the inner housing 20.
A support ring 2 protruding in the axial direction A from a flange 22 of
It fits into the spigot joint part 23a of No. 3. 1
Reference numeral 3 designates a retainer ring made of heat-resistant steel, which is integrally formed with an annular flange portion 14, an engaging portion 15, and a spring portion 16 that elastically connects the two flange portions 14, 15. This retainer ring 13 is fixed by pressing the outer peripheral end portion 93 and the collar portions 81d, 82d to the support ring 23 via a cushion material 17 such as graphite. In addition,
The spring portion 16 extends spirally in the axial direction A, and is integrally machined from the material of the retainer ring 13. Further, 18 is a heat shield.

In the above configuration, since the scroll 6 shown in FIG. 1 is divided into an outer cylinder 8 and an inner cylinder 9, the inner and outer cylinders 9, 8 are less susceptible to thermal stress due to temperature differences or rapid temperature changes. Become.

By the way, the scroll outer cylinder 8 is the combustor inner cylinder 3.
Since it is connected to the inner cylinder 9, it becomes more complicated than the inner cylinder 9.
However, since the scroll outer cylinder 8 is divided in the circumferential direction as shown in FIG.
2 do not restrain each other in the circumferential direction, large thermal stress due to uneven circumferential temperature distribution is unlikely to occur despite the complex shape.

Further, the scroll 6 shown in FIG. 1 has a complicated shape, and in particular, its outer cylinder 8 is connected to the combustor inner cylinder 3.
Since it is connected to a, the shape becomes even more complicated.
Therefore, as described above, the scroll 6 is divided into the inner and outer cylinders 9, 8, and the outer cylinder 8 is divided into each divided body 8.
By dividing the scroll into 1.82 pieces, it becomes easy to make the scroll 6 from ceramic.

By the way, by dividing the scroll outer cylinder 8 as described above, each divided body 81, 8 in FIG.
It is inevitable that a gap S will occur between the two. Here, since overlapping margins 81c and 82c are provided at the divided ends of the divided bodies 81 and 82 to cover the gap S, leakage of the combustion gas G from the gap S can be suppressed.

In addition, in this embodiment, the overlap margin 81 in FIG.
c, 82c are formed in the center part excluding both ends 8b in the axial direction A, so that the second inner cylinder 9 in FIG.
2 and the outer cylinder 8 can be connected by the spigot joint part 92a or the retainer ring 13.

In addition, in this embodiment, the scroll 6 is oriented in the axial direction A.
However, the combustion gas G in Fig. 2 has a certain width.
Needless to say, this invention can also be applied to a structure in which the width of the scroll 6 becomes narrower in the third axial direction A as it goes downstream.

[Effects of the invention] As explained above, according to this invention, the ceramic scroll is divided into an inner cylinder and an outer cylinder,
Furthermore, since the outer cylinder is divided in the circumferential direction, thermal stress is less likely to occur, and the ceramic scroll can be manufactured easily. In addition, since an overlap allowance is provided at the circumferential divided ends of the outer cylinder divided body,
It is possible to suppress combustion gas from leaking from the gaps between the respective divided bodies.

[Brief explanation of the drawing]

Figure 1 is a schematic sectional view of a gas turbine showing an embodiment of this invention, Figure 2 is a cross-sectional view of the outer cylinder, and Figure 3 is a cross-sectional view of the outer cylinder.
The figure is a perspective view showing a part of the outer cylinder, and FIG. 4 is an enlarged sectional view showing a method of holding the outer cylinder. 3...Combustor, 3b...Discharge end, 5...Turbine, 6...Scroll, 8...Outer cylinder, 81,8
2...Divided body, 81c, 82c...Overlap allowance, 9...
...Inner cylinder, S...Gap.

Claims (1)

[Scope of utility model registration request] A ceramic scroll of a gas turbine that directs combustion gases from a combustor to the turbine, the scroll extending generally radially of the gas turbine, the scroll forming a radially outer portion thereof and extending to a discharge end of the combustor. The outer cylinder is divided into a connected outer cylinder and an inner cylinder connected to the outer cylinder to form a radially inner part, and the outer cylinder is composed of a plurality of divided bodies in the circumferential direction, and each divided body is a ceramic scroll for a gas turbine that has an overlapping margin that covers the gap between the divided ends in the circumferential direction.