JPS60209604A - Gas turbine stationary blade - Google Patents

Abstract

PURPOSE:To contrive to decrease the cooling air by a method wherein only two blades at the both ends among stationary blade segments are integrally cast with a shroud, plural ceramic blades are fixed between those both end blades. CONSTITUTION:Only two blades 1 at the both ends among stationary blade segments are accurately and integrally cast with an inner shroud 4 and an outer shroud by a superalloy, plural ceramic blades 2 are fixed between those end blades. A cooling air which is not required for ceramic blades 2 is able to utilize for cooling of superalloy stationary blades 1, accordingly, the cooling air can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas turbine stator vane, and more particularly to the structure of a gas turbine stator vane segment.

High-temperature gas turbine air-cooled blades have traditionally been made by precision casting of superalloys, and are air-cooled from within to keep the temperature of the metal parts as low as possible. Generally, in order to improve the efficiency of a gas turbine, it is better to increase the gas temperature while reducing the amount of cooling air, but in this case, the blade metal temperature increases,
leading to premature damage.

In view of the above situation, the present invention aims to prevent the cooling efficiency from decreasing even with a small amount of cooling air, or to increase the cooling efficiency without changing the amount of air.

The present invention provides a gas turbine stationary blade segment in which an inner shroud, an outer shroud, and a plurality of blades therebetween are integrally cast. A gas turbine stationary blade has a plurality of ceramic fittings installed in the space between the blades.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to preferred embodiments thereof, which are illustrated in the accompanying drawings.

High-temperature gas turbine stationary blades are formed by consecutively juxtaposing segments as shown in Figure 1, and each segment consists of an inner shroud 4, an outer shroud 3, and a blade provided between them made of precision cast superalloy. It is cast in one piece. According to the present invention, first, only the stator blades 1.1 at both ends of this segment are left, and the intermediate stator blades are removed, and the inner and outer shrouds 4.3 are integrally cast by precision casting of superalloy. In this case, it goes without saying that the stator blade 1.1 made of superalloy has an air-cooled structure as compared to the conventional one.

Now, the intermediate stator vane mentioned above is separately manufactured from a ceramic material. This is a non-cooling system that does not employ an air-cooled structure. This is installed by fitting it into a superalloy integrally cast segment, and its installed state is shown by reference numeral 2 in FIG.

The attachment of the ceramic stator blade 2 will be further explained with reference to FIG. 2.

FIG. 2 is an enlarged longitudinal cross-sectional view of only the center portion of FIG. 1 (excluding the superalloy stator vane 1), and clearly shows the mounting structure of the ceramic stator vane 2. As is clear from this figure, the outer shroud 3 is provided with a groove 5 having an inverted conical cross section, the head 6 of the ceramic stator blade 2 having a conical cross section is inserted into the groove, and the tip 7 of the ceramic stator blade 2 is inserted into the groove. It is inserted into the groove 8 of the shroud 4. A cover 9 is placed on the outside of the outer shroud 3 by a port 10, and the head 6 of the ceramic stator vane 2 and the cover 9
A coil spring 11 is provided between the two.

The ceramic stationary blade 2 is pressed downward by the biasing force of the coil spring 11.

Ceramic stator blades have high rigidity and high temperature strength, that is, they can withstand high temperatures and have excellent strength at high temperatures, so they do not need to be cooled. Furthermore, at high temperatures, the ceramic stator vane 2 and the superalloy outer shroud 3 are misaligned between their heads 6 and grooves 5 due to a difference in thermal expansion. However, as mentioned above, the head 6 is connected to the coil spring 11.
Since it is pushed in firmly, the taper of the head 6 and the taper of the groove 5 come into close contact, and the ceramic stator vane 2 does not come loose from the outer shroud 3.

According to the present invention, the temperature of the metal blade of the stator blade 1 can be reduced because cooling air can be directed to the superalloy stator blade 1 to the extent that the ceramic stator blade does not require cooling air. If the cooling efficiency is kept constant, the amount of cooling air can be reduced. Furthermore, since the ceramic stator vanes are pressed by the coil springs, the ceramic stator vanes can be firmly held even if there is thermal expansion of the metal.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a gas turbine stationary blade cement according to the present invention, and FIG. 2 is a longitudinal sectional front view of the main parts thereof. 1. Super metal stator vane, 2. Ceramic stator vane, 3. Outer shroud, 4. Inner shroud, 5. Groove, 6. Head, 7. Tip, 8. Groove, 9-・Cover, 10... Bolt, 11... Coil spring. Figure 1 Figure 1

Claims (1)

[Claims] In a gas turbine stator vane segment in which an inner shroud, an outer shroud, and a plurality of blades in between are integrally cast, only the two blades at both ends of this segment are integrally cast in metal together with both shrouds, and the gap between the blades at both ends is A gas turbine stationary blade is made up of multiple ceramic fittings installed in a space.