JPS5917326B2 - Heat shielding structure for walls exposed to high heat using ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat shielding structure for a wall surface exposed to high heat using ceramics, and particularly to a support structure for a ceramic block on the wall surface.

In devices that have walls that are exposed to high heat, such as the combustor inner cylinder of a gas turbine, in order to protect the walls from high heat and maintain mechanical strength, for example, as shown in the partial perspective view shown in FIG. It has been proposed to cover the wall of the cylinder 1 with a ceramic block 2.

In the figure, 3 is an outer cylinder, and 4 is a passage for cooling air.

By the way, when attaching the ceramic block, for example, as shown in the partially enlarged perspective view shown in FIG. A method is used in which wedge-shaped support protrusions 6 provided in sintered zirconium are fitted.

In this case, it is necessary to install the ceramic block 2 less [on the side], but for this purpose, the ceramic block 2 including the support protrusion and the wedge-shaped support groove 5 provided on the inner cylinder are required.
Dimensional accuracy must be strictly maintained.

However, in reality, it is difficult to satisfy this requirement, so when the wedge-shaped support protrusion 6 is inserted into the wedge-shaped support groove 5, it may or may not fit in, or even if it does, there is often a large deviation. .

Therefore, for example, from among a large number of ceramic blocks,
Since it is necessary to select and assemble items that can fit in small quantities, the operation becomes very complicated.

In addition, there is a difference in thermal expansion coefficient between the metal body that forms the inner cylinder and the ceramic block, so even if they are fitted tightly, when heat is applied, the inner cylinder expands more than the ceramic block, causing the installation to fail. There is a risk of causing damage.

Furthermore, due to the difference in thermal expansion caused by temperature cycles during operation and stoppage, stress may act on the fixed and immovable ceramic block, causing damage to it.

The object of the present invention is to provide a ceramic block mounting structure that can eliminate all at once the complexity of assembling the ceramic block to the inner cylinder and the occurrence of uneven mounting due to thermal expansion. Next, the details will be explained using the drawings.

3, 4, and 5 are partial views of the inner cylinder wall surface from which some ceramic blocks have been removed, showing an embodiment of the present invention in the combustor inner cylinder of a gas turbine, and the A-A' section thereof. A-
It is an enlarged cross-sectional view of a portion in the direction of arrows in the N section, and the same reference numerals as in FIGS. 1 and 2 indicate the same parts.

In Fig. 3, 1 is the inner cylinder, 2 is the ceramic block,
This is attached by fitting the wedge-shaped support protrusion 6 into the wedge-shaped support groove 5 provided on the wall surface of the inner cylinder 1, as in the conventional case, but in the present invention, the support part of the ceramic block, etc. It is designed to facilitate assembly by having a characteristic structure as explained in .

The first characteristic is that the wedge-shaped support protrusion 6 has an angle 7 between the wedge-shaped support protrusion 6 and the wedge-shaped support groove 5 to the extent that the wedge-shaped support protrusion 6 does not fall out, as shown in FIG. , wedge-shaped support projection 6
The dimensions of the ceramic blocks 2 are made smaller than those of the wedge-shaped support grooves 5, and the spaces 8 are formed between adjacent ceramic blocks on the upper, lower, left and right sides as shown in FIGS. 3 and 4.
The reason lies in the selection of the size of the .

As a result, the bottom surface of the wedge-shaped support protrusion 6 is pushed in the radial direction of the inner cylinder 1, and as shown in FIG. It was designed so that

Secondly, near the center of the assembly position of the ceramic block 2, as shown in FIGS. 3 and 4, a cooling air passage 4 and a wedge-shaped support strip are provided which penetrate through the inner cylinder 1 and which are explained in FIG. One or more cylinders (the figure shows the case of one) connect the inside of the groove 5.

) is provided, and cooling air is fed into the wedge-shaped support groove 5 through this, and the pressure causes the bottom surface of the wedge-shaped support protrusion 6 to blow in the direction of the arrow in the figure, as shown in FIG. It is designed to apply a pressing force of .

In this way, a bias is created in advance between the wedge-shaped support groove 5 and the support protrusion 6, and the support protrusion 6 hits the inner wall side of the support groove 5 and is supported by the pressure of the cooling air. This not only makes it extremely easy to assemble the ceramic block into the inner cylinder, but also reduces manufacturing costs since dimensional accuracy is not required.

Furthermore, even if the wedge-shaped support groove 5 becomes larger due to thermal expansion, the ceramic block 2 is pushed by the pressure of the cooling air.
Since the side wall surface thereof is moved and pressed so as to be in contact with the side wall surface of the groove 5, there will be no rattling during installation.

Furthermore, according to the present invention, when the ceramic block 2 is pushed by cooling air, a gap 10 is automatically formed at the bottom of the wedge-shaped support protrusion 6 and the support groove 5, as shown in FIG. Also, a gap 11 is formed between the wall surface of the inner cylinder 1 where the support groove 5 is not installed and the back surface of the ceramic block 2.

Therefore, there is a void 10 outside the one due to the ceramic block 2.
, 11, which not only greatly promotes the thermal protection of the inner cylinder wall surface, but also has the effect of alleviating the impact applied to the ceramic block since the void 10 acts as an air spring. Motsu.

Also, since ceramic blocks can move relative to the wall,
There is no risk of damage due to stress due to differential thermal expansion due to temperature cycles.

In the above description, the wall surface of the inner cylinder was cut out to provide the wedge-shaped support grooves 5, but as shown in the partially enlarged sectional view shown in FIG.
A plurality of strips 12 having an L-shaped cross section may be fixed to the inner cylinder wall surface so that the cross section is wedge-shaped.

In addition, in the above example, the wedge-shaped support groove 5 is formed on the inner cylinder 1 side. Although the wedge-shaped support protrusion 6 is provided on the ceramic block 2 side, its installation position may be reversed as shown in the partially enlarged sectional view shown in FIG.

Furthermore, in the above description, the shape was made to match the curved wall surface of the inner cylinder 1 in the shape of the ceramic block 2, but as shown in the partial sectional plan view shown in FIG. 8, the wall surface of the inner cylinder 1 is formed into a polygonal shape, You can also make the shape of the ceramic block 2 into a flat plate by making sure that the wall surface on which the block 2 is installed is flat.
.

Furthermore, although an example of application to the combustor inner cylinder of a gas turbine has been described above, excellent effects can be obtained by using it to protect a wall surface exposed to high heat in a gas turbine blade, an MHD power generation device, or the like.

Furthermore, in the above example, cooling air was used as the air for suppressing and moving the ceramic block 2, but if the device does not have a cooling air source, or if it is difficult to use even if it does, the present invention can be carried out by providing an air source independently. can.

As is clear from the above description, according to the present invention, in thermally protecting a wall surface exposed to high heat using a ceramic block,
It is possible to provide a heat-insulating structure for walls exposed to high heat, which has excellent effects such as making the assembly and fabrication of ceramic blocks much easier than before, and the practical effects are remarkable.

[Brief explanation of drawings]

Figures 1 and 2 are partial perspective views showing conventional examples of thermal protection of the inner cylinder wall surface of a gas turbine combustor using ceramics;
4 and 5 are perspective views of one embodiment of the present invention,
Of these, Fig. 3 is a partial view of the inner cylinder wall surface with a part of the ceramic block removed, Fig. 4 is an enlarged cross-sectional view of the part A-1 in the direction of the arrow, and Fig. 5 is an arrow-headed view of the A-1 part in the operating state. FIG. 3 is a partially enlarged sectional view. 6, 7, and 8 are partially enlarged sectional views showing modified examples of the present invention. 1... Combustor inner cylinder, 2... Ceramic block, 3
... Outer cylinder, 4... Cooling air passage, 5... Wedge-shaped support groove, 6... Wedge-shaped support protrusion, 7... [Backlash], 9.
...Cooling air supply path, 10, 11...Gap, 12.
-... Wedge-shaped support groove forming strip.

Claims (1)

[Scope of Claims] 1. A supported convex portion (support recess) with a wedge-shaped cross section provided on a ceramic block is fitted into a support recess (supported convex portion) with a wedge-shaped cross section provided on a wall surface exposed to high heat. In a heat-insulating structure in which the wall surface is covered and protected by a ceramic block, the wedge-shaped supported portion is formed such that the wedge-shaped supported convex portion does not come out from the wall-side opening of the wedge-shaped support recess. and the wedge-shaped support recess, and a gap is provided between adjacent ceramic blocks so that the ceramic blocks are movable to create a gap between them and the wall surface exposed to high heat, and the air flowing to the bottom of the wedge-shaped support recess is A ceramic block is provided with a supply path so that the supply air pressure pushes the bottom of the wedge-shaped supporting convex part and holds it in the wedge-shaped supporting concave part, thereby holding the ceramic block on the wall surface exposed to high heat and performing heat insulation. Heat shield structure for walls exposed to high heat.