JPH108903A - Structure for ceramic gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an inner/outer circumference temperature difference of a back plate so as to reduce stress, by providing a hole, inserted toward a surface of a bearing housing side from a surface of a turbine side, in a plate part extended in a diametric direction of the back plate, and allowing a part of high temperature gas to flow in an inner circumferential side surface of the back plate. SOLUTION: From a turbine side surface 1b of a plate part 1d extended in a diametric direction of a back plate 1, a through hole 1a is formed in a surface 1c in a side of a bearing housing 9. The through hole 1a, from the turbine side surface 1b in the more outside periphery than the periphery of a back plate 3a of a turbine, is obliquely opened toward the surface 1c in a side of the bearing housing. In this way, by a differential pressure between a back plate of a turbine 3 and its periphery, a part of high temperature gas flows through the through hole 1a, a very small amount of high temperature gas flows from the periphery toward the inner circumference along a surface of the back plate 1 from the through hole 1a, an inner circumferential side of the back plate is heated by high temperature gas, an inner/outer circumference temperature difference is reduced, to reduce generated stress, and durability of the back plate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of a ceramic gas turbine.

[0002]

2. Description of the Related Art As a structure of a conventional ceramic gas turbine, for example, there is one as shown in FIG.

The turbine 3 is driven by the high-temperature and high-pressure gas discharged from the scroll 2, and rotational energy is obtained through a shaft 4. Since the high-temperature high-pressure gas exceeds 1300 ° C., the back plate 1, the scrolls 2, 2 ′, and the turbine 3 are formed of ceramic.

Since high-temperature and high-pressure gas exceeds 1300 ° C.,
Although the temperature of the turbine becomes high, the temperature of the bearing must be 150 ° C. or less in order to secure the lubrication performance because the bearing 5 is oil-lubricated. For this reason, the back plate 1 is provided on the back plate side of the turbine to form a flow path for high-temperature and high-pressure gas, and to shield radiant heat to the bearing housing 9.

[0005] Reference numeral 7 denotes an oil supply passage for supplying lubricating oil to the bearing 5.

A supply passage opening in a turbine shaft insertion hole 9b between the seal rings 6 to prevent high-temperature and high-pressure gas from flowing into the bearing 5 and prevent oil from the bearing 5 from flowing into the turbine-side space 10. 8 is provided to discharge the seal air to the space 10 on the turbine side.

[0007]

However, in the structure of such a conventional ceramic gas turbine,
Since the outer periphery of the back plate 1 is heated by contact with the high-temperature ceramic component, and the inner periphery is cooled by heat radiation to the bearing housing 9 and sealing air,
There is a possibility that a large temperature difference occurs between the inner and outer circumferences of the back plate 1 and an excessive stress is generated on the inner circumferential side, so that the durability of the back plate 1 is reduced.

The present invention has been made in view of such a conventional problem, and a hole penetrating from a surface on the turbine side to a surface on the bearing housing side in a plate portion extending in the radial direction of the back plate. It is an object of the present invention to solve the above problem by flowing a part of the high-temperature gas to the inner peripheral surface of the back plate to reduce the temperature difference between the inner and outer periphery of the back plate and reduce the stress.

[0009]

In order to solve the above-mentioned problems, a structure of a ceramic gas turbine according to the present invention includes a scroll for accommodating a turbine, forming a gas flow path to the turbine, and a bearing for a turbine shaft. In a ceramic gas turbine having a back plate on a turbine back plate side between a bearing housing to be accommodated and a scroll and a bearing housing, a plate portion extending in a radial direction of the back plate is provided with a plate portion extending from an outer peripheral side of the turbine back plate. A plurality of through holes penetrate in the axial direction toward the bearing housing side surface.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the same parts, members, and the like as those described in the related art will be described using the same reference numerals.

(First Embodiment) FIGS. 1A and 1B
FIG. 1 is a diagram showing a first embodiment of the present invention.

First, the structure will be described. Reference numeral 1 denotes a back plate, and a through hole 1a is formed in a surface 1c of a bearing housing 9 from a turbine side surface 1b of a plate portion 1d extending in a radial direction of the back plate 1. I have.

The through-hole 1a is obliquely opened from the turbine-side surface 1b on the outer periphery of the back plate 3a of the turbine 3 to the bearing housing 9-side surface 1c. A plurality of the through holes 1a are formed on the circumference.

Next, the operation of the first embodiment will be described.
Due to the pressure difference between the back plate 3a of the turbine 3 and the outer periphery of the turbine 3, a part of the high-temperature gas flows through the through hole 1a. A very small amount of high-temperature gas is passed through the through-holes 1a opened diagonally.
It flows along the surface of the back plate 1 from the outer periphery to the inner periphery. For this reason, the inner peripheral side of the back plate 1 is heated by the high temperature gas, and the temperature difference between the inner and outer peripheries is reduced, so that the generated stress can be reduced.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. In the second embodiment,
A plurality of holes 8a are provided so that a part of the seal air 8 is blown from the outer periphery to the inner periphery of the bearing housing portion 9a.

In the first embodiment, the back plate 1
By flowing a hot gas over the surface of the
Becomes high temperature, the bearing housing 9 receives radiant heat from the back plate 1, and the temperature of the bearing portion becomes high.

For this reason, by providing a hole through which a part of the sealing air flows along the surface of the bearing housing portion 9a and forming an air curtain on the surface of the bearing housing portion 9a, it is possible to prevent the temperature of the bearing housing from becoming high. I have.

The direction of the flow of the seal air is the same as the direction of the gas flow on the back plate surface, so that the flow of the high-temperature gas on the back plate surface is not disturbed and the temperature distribution on the back plate surface is not uneven. I have.

(Third Embodiment) Next, a third embodiment will be described with reference to FIGS. 3 (a) and 3 (b). A plurality of holes penetrating the back plate are provided with a swirl angle to make the gas flowing on the back plate surface uniform, thereby making the surface temperature uniform. Thereby, local thermal stress caused by flowing the combustion gas from the plurality of holes can be reduced.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIGS. 4 (a) and 4 (b). Instead of the sealing air outlet 8a, a ring 11 is formed on the outer circumference of a ring 12 having a slit with a turning angle, and the slit 12 'is formed as an outlet. This facilitates the manufacture, as compared with the case of forming a plurality of holes having a turning angle in the radial direction on the circumference as in the second embodiment.

(Fifth Embodiment) Next, a fifth embodiment will be described with reference to FIG. In the fifth embodiment,
In addition to the above-described first to fourth embodiments, a plurality of outlet holes 8 ″ for the seal air are formed so as to face the hot gas outlet holes on the back plate. The direction of the flowing high-temperature gas is forced from the outer peripheral side to the inner peripheral side, so that the high-temperature gas flows to the back plate surface, and a part of the seal air flows to the bearing housing surface.

[0022]

As described above, according to the present invention, the structure is such that the hole passing through the back plate from the turbine side to the bearing housing gas side is provided on the outer periphery than the back plate of the turbine. The effect that the back plate can be prevented from being damaged is obtained.

Each embodiment has the following effects in addition to the above-mentioned common effects.

According to the ceramic gas turbine structure of the second embodiment, radiant heat due to a high temperature of the back plate can be prevented.

According to the ceramic gas turbine structure of the third embodiment, the high temperature gas flowing through the back plate can be made uniform, and the occurrence of thermal stress due to a local temperature difference can be prevented.

According to the ceramic gas turbine structure of the fourth embodiment, the structure for forming the air curtain on the bearing housing side surface can be easily manufactured.

According to the ceramic gas turbine structure of the fifth embodiment, the structure is such that the temperature of the back plate can be made uniform and the bearing housing can be cooled by the seal air.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a front view of a back plate according to a third embodiment of the present invention.

FIG. 4 is an explanatory view of a seal air blowing hole according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a fifth embodiment of the present invention.

FIG. 6 is a view showing a structure of a conventional ceramic gas turbine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Back plate 1a Hole in back plate 2 Scroll 3 Turbine 4 Shaft 5 Bearing 6 Seal ring 8 Seal air introduction hole 9a Bearing housing

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location F02B 39/00 F02B 39/00 U

Claims (2)

[Claims] 1. A scroll for accommodating a turbine and forming a gas flow path to the turbine, a bearing housing for accommodating a bearing of a turbine shaft, and a back plate on a turbine back plate side between the scroll and the bearing housing. A ceramic gas turbine comprising: a plate portion extending in a radial direction of a back plate; and a plurality of through holes penetrating in an axial direction from a position on an outer peripheral side of the turbine back plate toward a bearing housing side surface. The structure of a ceramic gas turbine. 2. A seal air passage opening in a turbine shaft insertion hole between a bearing and a turbine is provided in a bearing housing, and the seal air passage is branched to extend to an outer peripheral position of a turbine-side end face of the bearing housing. The structure of the ceramic gas turbine according to claim 1, wherein an opening is formed on an inner peripheral side along the end face.