JPH0335987Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support structure for a heat shield in a gas turbine combustor, particularly to prevention of damage to the heat shield.

In gas turbines, efforts are being made to increase the gas temperature to around 1500°C, which is much higher than the current temperature, in order to improve efficiency. In this case, it is necessary to protect the metal inner cylinder wall surface of the gas turbine combustor from high temperatures to maintain mechanical strength, and if this is not achieved, no improvement in efficiency can be expected by raising the temperature of the gas. Therefore, the present inventor previously proposed the following structure in which the inner cylinder wall surface can be effectively protected by covering the inner cylinder wall surface with a heat-resistant block, such as a ceramic block made of silicon carbide. That is, as shown in the partial perspective view shown in FIG. Support bodies 3b having supporting protrusions 3a on the upper part are provided in parallel at intervals. On the other hand, a flat heat-shielding ceramic block 4 (hereinafter referred to as the ceramic block) shown in the perspective view of FIG. A ceramic block 4 is made with a support groove 4b into which the block is inserted. Then, as shown in the sectional view shown in FIG. 3, this is fitted from the end of the inner cylinder 3 so that the supporting protrusion 3a enters the support groove 4b of the ceramic block 4. A screw 7 screwed into a screw hole 6 provided in the inner cylinder 3 pushes up and fixes the ceramic block 4 through a heat insulating packing such as a ceramic fiber 8 and a fixing rod such as a ceramic rod 9. A connecting hole (not shown) provided through the cylinder 3 allows the cooling air in the cooling air circulation space 1 to flow into the cooling air circulation space 5 as well.

According to this structure, the surface of the metal inner cylinder 3 is shielded from high temperatures through the ceramic block 4 and the gap 5, which are cooled by cooling air, and the inner cylinder 3 is further cooled from the inside and outside by the cooling air. Ru. Therefore, the inner cylinder 3 can be protected from the high temperature of the gas and its mechanical strength can be maintained for a long period of time. However, as a result of long-term operation experiments, it was revealed that this structure has the following drawbacks.

That is, in this structure, since the ceramic block 4 is in direct contact with the high-temperature combustion gas, the temperature is almost close to the gas temperature, for example, 1200°C or higher, whereas the inner cylinder 3
is at a temperature that maintains its mechanical strength, e.g.
It is cooled to about 800℃. Therefore, as shown in FIG. 3, a low-temperature inner cylinder 3 is located between the thin upper and lower tongues 4c and 4d of the left and right grooves 4b of the high-temperature ceramic block 4.
The supporting protrusion 3a will be located. For this reason, especially the lower tongue 4d in contact with the inner cylinder 3 is constantly subjected to a thermal strain force due to a large temperature difference.
As a result, during long-term operation, the lower tongue 4d may break and the ceramic block 4 may fall off the wall of the inner cylinder 3, making it impossible to provide thermal protection.

The present invention eliminates the above-mentioned drawbacks and enables long-term operation of a gas turbine combustor.
Next, the details will be explained using the drawings.

FIG. 4 is a partial cross-sectional view showing an embodiment of the present invention;
FIG. 5 is a perspective view of the support, and the feature of the present invention is that the support 10 of the ceramic block 4 to the inner cylinder 3 is separately made of high temperature resistant ceramic such as silicon nitride. The main feature is that this is made and fixed to the wall surface of the inner cylinder 3 via a highly heat-resistant heat insulating material such as ceramic fiber 11.
That is, as shown in FIG. 4, it has a height sufficient to create a cooling air circulation space 5 between the wall surface of the inner cylinder 3 and the ceramic block 4, and has grooves 4b for supporting left and right of the ceramic block 4 on the left and right ends of the inner cylinder 3. Ceramic support 10 with a support protrusion 10a that goes inside
and make a two-stage hole 10b with this in the center.
Then, it is fixed to a predetermined position on the wall surface of the inner cylinder 3 via the heat insulating material 11 using a through hole 3c provided in the inner cylinder and heat-resistant metal bolts and nuts 12, 13 corresponding to the width of the ceramic block. It is designed to hold a ceramic block 4. Note 14
is a position regulating groove of the support body 10.

In this way, the temperature of the ceramic support 10, which largely restricts the transfer of heat to the inner cylinder 3 by the heat insulating material 11, is close to the temperature of the ceramic block 4 for heat shielding supported by the ceramic support 10. becomes. Therefore, as in the conventional case, the thermal distortion force due to the large temperature difference between the ceramic block 4 and the inner cylinder 3 is applied to the lower tongue 4 of the groove 4b of the ceramic block 4.
d can be well avoided, and its damage can be effectively prevented.

The present invention has been explained above using one embodiment, but the sixth embodiment
As shown in the partial cross-sectional view shown in the figure, a heat-resistant cushioning material, for example, a cushioning material 15 such as ceramic wool, is provided between the supporting protrusion 10a of the ceramic support 10 and the lower tongue 4d of the ceramic block 4. The lower tongue 4d, which is kept at a high temperature, may be prevented from breaking by buffering the tightening force by a fixing rod 9 made of a heat insulating material shown in FIG. 4 or the like. Alternatively, the two-step mounting hole 10b provided in the support 10 may be formed in an elliptical shape as shown by the dotted line in FIG. 5, so that the mounting position of the support 10 on the inner wall surface can be adjusted. good. Further, in the above description, the support body 10 is formed into a piece as shown in FIG. 5, but it goes without saying that the support body 10 may have a length extending over the entire length of the inner cylinder if sufficient strength is obtained. Furthermore, in the above example, the ceramic block 4 is pushed up and fixed by a ceramic fixing rod 9 as shown in FIG. 4, but any fixing means such as a spring made of heat-resistant metal can be used. can.

As is clear from the above description, the present invention has the excellent advantage of effectively preventing damage to the supporting portion of the ceramic block due to the temperature difference between the ceramic block for heat shielding and the inner cylinder. This contributes to the realization of a long-life gas turbine combustor.

[Brief explanation of the drawing]

1, 2 and 3 are explanatory diagrams of a conventional heat shielding structure using a ceramic block, and FIGS. 4 and 5 are a partial cross-sectional view and a perspective view of a support body showing an embodiment of the present invention. , FIG. 6 is a partial cross-sectional view showing a modification of the present invention. 1...Cooling air circulation space, 2...Outer cylinder, 3...
Inner cylinder, 3a... support protrusion, 3b... support body,
4... Ceramic block for heat shielding, 4b... Supporting groove, 4c... Upper tongue, 4d... Lower tongue, 5...
... Cooling air circulation air, 6 ... Screw holes for fixing, 7
... Fixing screw, 8 ... Heat insulating packing, 9 ... Heat insulating fixing rod, 10 ... Support body, 10a ... Supporting protrusion, 10b ... Double hole for fixing, 11 ... Heat insulating material, 12, 13...Boruto, Natsuto, 14...
Support position regulating groove, 15...Insulating cushioning material.

Claims (1)

[Scope of utility model registration request] A highly heat-resistant support body having supporting protrusions on the left and right sides of the upper end is fixed to the inner cylinder wall surface at a predetermined interval via a highly heat-resistant heat insulating material, and the left and right ends of the heat shielding ceramic block body are The support protrusion of the highly heat-resistant support is inserted into a support groove opened laterally in the support groove, and the heat-shielding ceramic block is fixed to the inner cylinder wall with a cooling air flow gap. A mounting structure for a heat shield in a gas turbine combustor, characterized in that: