JPH0357282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rotating equipment such as turbomachinery, and more particularly to ceramic turbine blade assemblies having ceramic shields for thermally protecting blades and vanes against high temperature operations. It is something.

In order to improve the performance of turbomachinery, such as pumps and turbines, and to improve fuel efficiency, it has been proposed to operate the turbine by increasing the turbine inlet temperature. Theoretically, it is desirable to operate at an inlet temperature of 1315°C (2400°C) or higher. However, such high temperatures are far beyond the operational limits for use without the need for complex and expensive cooling methods, even using today's most advanced high strength metals. The most likely possibility to use high inlet temperatures without using complex cooling methods is to use high temperature ceramics. However, the problem with ceramics is that they are brittle in nature. Furthermore, manufacturing ceramic turbine components with high strength and highly dimensionally accurate shapes was expensive, as the prior art methods required hot pressing and polishing. Accordingly, years of research and development have been conducted and significant amounts of money have been spent to develop improved methods of manufacturing ceramic turbine components that minimize tensile stresses within the ceramic.
Ceramic components have also been proposed as being able to withstand the abrasion and erosion of materials such as, for example, coal slurry. Many ceramic rotors and rotor blades have been produced and tested. However, such rotors and blades are subject to tensile forces within a centrifugal force field and are therefore in a state where they are easily destroyed.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a ceramic turbine blade assembly that eliminates the drawbacks of the prior art as described above.
In the present invention, the thermally insulating shield or sleeve is formed of a ceramic material, while metal is used to provide strength against the tensile force of centrifugal force. A ceramic shield is attached to a thermally protected metal structure so that it is only subjected to compressive forces caused by Furthermore, the present invention enables ceramic parts to be mass-produced at low cost, has extremely high uniformity, and has excellent properties in terms of strength, density, and surface finish even in the case of complex shapes. The present invention provides an injection molding technology that allows parts to be manufactured.

Accordingly, it is an object of the present invention to provide an improved ceramic turbine blade assembly.

Another object of the present invention is about 1315°C (2400°C).
〓) It is an object of the present invention to provide a turbine component that can use the above inlet temperature.

Yet another object of the invention is to provide dimensions and apparatus for manufacturing turbomachinery components using ceramic materials.

A particular object of the invention is to provide a turbomachine with a thermally insulating field or sweep made of ceramic material which is only subjected to compressive loads and which surrounds the metal elements to provide resistance to centrifugal and tensile forces. The purpose is to provide parts.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. In order to meet the high temperature and corrosion characteristics of modern turbomachinery, the prior art has proposed using parts such as the turbine wheel shown by number 2 in Figure 1 as ceramic parts. There is. Prior art ceramic carbon wheels typically have a plurality of vanes 4, which can be integrally formed with the turbine hub 6, as shown at 8, or which can be integrally formed with the hub 6. It is also possible to form it as a removable insert having legs 10 engageable in suitable slots 12 provided in the insert. however,
When the wheel 2 is rotated, a centrifugal force acts on the blade 4 in the form of a tension, which condition is indicated in FIG. 1 by the arrow 14. Such prior art ceramic turbomachinery components have been unsatisfactory because ceramics are brittle and are particularly susceptible to tensile failure.

2-4 illustrate a turbine wheel 16 constructed in accordance with the present invention, in which a metal hub 18 carries a plurality of blades, as indicated by the numeral 20. Each of the wings 20 has a ceramic shield 22, the shield 22
has a suitable hydrodynamic external shape as best shown in FIG. 4, and as shown in FIG.
It surrounds a metal core 24 attached to the hub 18. Shield 22 is secured to core 24 by a metal cap member 26. The core 24 can be integrally formed with the hub 18, in which case it is designated by the numeral 28 in FIGS. 2 and 3. Alternatively, the core 24 may be secured to the hub 18 by any suitable means, as shown by legs 30 in FIG. Similarly, the cap member 26 can be integrally formed with the core 24, as indicated by the numeral 32 in FIG. be. With this configuration, when the wheel 16 is rotated, the ceramic shield 22 is pressed against the cap member 26 by the force F, and in this case, the tensile load is applied to the metal core 24 and the cap member 2.
6 will be accepted. Therefore, the ceramic shield will only be subjected to compressive loads. It is known that ceramics have high strength against compressive loads.

Hot gases that drive the turbine wheel 16 flow through inlet and outlet conduits (not shown). Accordingly, the hot gas contacts the airfoil 20 in the area designated by numeral 36 in FIG. Ceramic shield 22 therefore provides thermal shielding for core 24.

A shoulder portion 38 is provided on the shield 22 and the cap member 2
It is desirable to provide thermal protection for 6. With this configuration, the space 40 is formed, so that thermal expansion of the shield 22 in the radial direction can be absorbed. Additionally, if necessary or desired, cooling passages 42 may be provided within the hub 18 to supply cooling fluid between the ceramic shield 22 and the metal core 24. As shown in FIGS. 3 and 4, a suitable recess 44 is provided in the ceramic shield.
A recess 44 between the shield 22 and the core 24 can be provided to allow cooling fluid to flow through the recess 44 between the cap member 26 and the shield 22 and out through a passageway 46 formed between the cap member 26 and the shield 22. . On the other hand, as shown in FIG. 5, cooling recesses 48 similar to the recesses 44 shown in FIG. 4 may be formed on the outer surface of the core 24. Since centrifugal force is not applied to the stator member, the conditions are more relaxed than those for the rotating member. Therefore, the cap member of the stator (not shown) can be made of ceramic, and can also be formed integrally with the shield.

6 is an exploded view of an alternative embodiment of the turbine blade of FIG. 2 having a metal blade core 50 integrally formed with a turbine wheel 52. FIG. However, the core 50 can also be formed separately and secured to the wheel 52 using any suitable attachment means. Ceramic shield 54 has an outer surface 56 shaped to provide the desired hydrodynamic shape and a central portion shaped to easily fit over wing core 50 and provide space therebetween. An opening 58 is formed. Wing sheet 6 formed of corrugated metal
0 is the core 50 and the shield 54 (number 44 in Figure 3)
(in the space indicated by ) to form a flexible layer. The layers include a core 50 and a shield 5
4, the shield 54 and the core 50
core 5 by suitable inlet and outlet passages formed in wheel 52 as shown in dotted lines at 62 and 64.
A plurality of channels are defined for cooling fluid to be introduced between the shield 54 and the shield 54. Wing cap 66 closes the outer end of opening 58. It is also possible to form a plurality of ridges at the lower end of the cap 66, as shown at 68, to allow cooling fluid to flow out of the outer end of the core 50. Alternatively, the wing cap 66 and shield 54 may be secured to the core 50 using a suitable adhesive (not shown) as shown in the wing of FIG.

Although specific embodiments of the present invention have been described in detail above, the present invention should not be limited to the above-mentioned specific examples, and it goes without saying that various modifications are possible within the technical scope of the present invention. It is.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional ceramic turbomachinery component, FIG. 2 is a partial sectional view of a turbine wheel having shielded blades according to the present invention, and FIG. 3 is a partial sectional view of the turbine wheel of FIG. 2. figure,
4 is a cross-sectional view of the blade of the turbine wheel of FIG. 2, FIG. 5 is a cross-sectional view of the blade of another embodiment of the turbine wheel of FIG. 2, and FIG. 6 is a cross-sectional view of the blade of the turbine wheel of FIG. 2. Exploded view of the wing. (Explanation of symbols), 16: Turbine wheel, 1
8: metal hub, 20: wing, 22: ceramic shield, 24: metal core, 26: cap member.

Claims (1)

[Scope of Claims] 1. In a ceramic turbine blade assembly, a metal blade core, a ceramic shield having an opening into which the blade core is inserted with a predetermined space even during operation, and a ceramic shield fixed to the blade and having a a cap member engageable with the shield to maintain the shield in place; a flexible corrugated compartment wall positioned within the space about the core; a shaped compartment wall having an inwardly projecting ridge engageable with the core and an outwardly projecting ridge engageable with the shield, thereby providing a peripheral surface of the core within the space; A ceramic turbine blade assembly defining a plurality of inner passageways and a plurality of outer passageways for flowing a cooling fluid thereon along a longitudinal axis thereof. 2. The ceramic turbine blade assembly according to claim 1, wherein the metal blade core has a base end portion fixed to a turbine rotor hub. 3 In claim 1 or 2,
A ceramic turbine blade assembly wherein the ceramic shield has a hydrodynamically shaped exterior surface. 4. In any one of claims 1 to 3, a plurality of protrusions are provided on the bottom of the cap member, and the plurality of passages are at least partially communicated with the outside. A ceramic turbine blade assembly characterized by: 5. In any one of claims 2 to 4, the cooling fluid supplied from the rotor hub may flow through a passage formed by the corrugated partition wall. A ceramic turbine blade assembly characterized in that: