JP3757999B2 - Scroll seal structure in gas turbine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas turbine having a scroll chamber that is disposed around a turbine shaft and supplies combustion gas to a turbine cascade, and more particularly to a scroll seal structure in a gas turbine.
[0002]
[Prior art]
As illustrated in FIG. 2, the gas turbine includes an air compressor 1, a combustor 2, a turbine 3, and the like, and fuel is burned by the combustor 2 using air pressurized by the air compressor 1, and the gas turbine is heated to a high temperature. The combustion gas 4 is generated, the turbine 3 is driven by the high-temperature combustion gas 4, and the air compressor 1 is rotationally driven by the turbine 3. Moreover, as shown in this figure, many gas turbines for onshore or aircraft auxiliary power have only a single combustor 2 from the standpoints of exhaust gas countermeasures, improved maintainability, cost, etc. In this case, a scroll chamber 5 for supplying the combustion gas 4 from the combustor 2 to the turbine blade row is provided.
[0003]
The scroll chamber 5 is usually a spiral hollow chamber disposed around the turbine shaft, and an outlet of the combustor 2 is attached to the outer peripheral portion thereof, and the flow area in the radially inner direction is configured to be small. The peripheral end opens in the axial direction, and the combustion gas is ejected in the axial direction to the turbine blade row.
[0004]
[Problems to be solved by the invention]
As described above, since the scroll chamber has a complicated shape, the scroll chamber is usually divided into a plurality of portions, and the spaces are connected by various structures as illustrated in FIG.
FIG. 3 (A) shows a case in which the scroll chamber 5 is divided into front and rear members which are fitted and joined by cylindrical fitting portions 6a and 6b extending in the axial direction, and (a) is a rear front edge. The front rear edge 5a is fitted inside the part 5b. (B) and (c) are the rear front edge 5b in a ring-shaped groove provided between the front rear edge 5a and the casing 7. These components are used when the front front edge portion 5b or the front rear edge portion 5a is a part when the pressure of the combustion gas 4 pulsates or fluctuates and the internal / external pressure difference of the scroll chamber 5 becomes excessive. There is a possibility that the compressed air from the compressor 1 flows in from the recessed portion and the output is reduced.
[0005]
3 (A) is proposed to solve the above-mentioned problem (Japanese Patent Laid-Open No. 4-241744), and the front rear edge 5a is formed into a curved shape, A curved reinforcing member extending in a curved shape along the inner peripheral surface of the front rear edge 5a is formed on the front edge 5b, and the front rear edge and the rear front edge without increasing the plate thickness. It is designed to withstand the internal / external differential pressure of the scroll chamber.
[0006]
However, even in the case of the sealing structure disclosed in Japanese Patent Laid-Open No. 4-241744, the inside of the fitting portion is directly exposed to high-temperature (about 1000 ° C.) combustion gas, and the outside is a relatively low temperature (about 400 ° C.) compressor outlet. Since it is exposed to air, (1) there is a large temperature difference between the two, and there is a problem that a large surface pressure acts on the fitting portion due to the difference in thermal expansion. In order to reduce this surface pressure, it is necessary to provide a relatively large initial gap. Gas leakage occurs from this gap in the initial stage of operation, and conversely, if the initial gap is too small, the surface pressure of the fitting portion increases. Permanent deformation may occur in the fitting portion. {Circle around (2)} The flow of combustion gas is uneven in the circumferential direction in the case of a can-type combustor at one circumference, and the fitting gap tends to be uneven in the circumferential direction during operation. (3) Further, since the parts constituting the fitting are supported independently, the parts are assembled with the fitting biased, and the fitting gap is further increased.
[0007]
Further, FIG. 3 (B) is a case where the front and rear portions of the scroll are connected and sealed by flanges 6 projecting from each, and there is no gap in structure, so that a complete seal can be achieved. However, it is necessary to take a sufficient axial length between the scroll body and the flange so that the thermal stress at the portion between the scroll body and the flange does not become excessive, and there is a problem that the axial length becomes long.
[0008]
The present invention has been made to solve such problems. That is, the object of the present invention is to be able to maintain a sufficient sealing property without causing a gap in the fitting portion with low stress while being exposed to a temperature difference and a pressure difference, and to reduce the axial length. An object of the present invention is to provide a scroll seal structure in a gas turbine that can be kept short.
[0009]
[Means for Solving the Problems]
According to the present invention, a hollow donut-shaped scroll outer ring portion that is disposed so as to surround the turbine shaft, and a scroll inner ring portion that is configured to have a small radial inner passage area and whose inner peripheral end is open to the turbine blade row The scroll outer ring portion and the scroll inner ring portion are connected by the outer peripheral fitting portion and the inner peripheral fitting portion, and the outer peripheral fitting portion is connected to the scroll outer ring. A female member having an axial gap at a position away from the part and a male member fitted into the gap at a position away from the scroll inner ring part. The inner end of the inward projecting portion is fixed to the scroll outer ring portion, and the inner end portion of the male member is attached to the scroll inner ring portion so as to be slidable in the radial direction. In a gas turbine characterized by Seal structure is provided.
[0010]
According to the configuration of the present invention, the scroll outer ring portion and the scroll inner ring portion are connected by the outer periphery fitting portion and the inner periphery fitting portion, and the outer periphery fitting portion is positioned away from the scroll outer ring portion. Since the whole fitting part is located in the low temperature part away from the scroll body of the high temperature part that is directly exposed to the combustion gas, it is connected to the fitting part for sealing. Thermal deformation does not occur. Further, with this configuration, since the fitting portion is located at a site separated from the scroll body, a wide degree of freedom can be obtained in designing the shape of the scroll body and the position of the combustor.
[0011]
According to a preferred embodiment of the present invention, the inward projecting portion of the female member has a curved portion that is curved in the axial direction. With this configuration, thermal deformation occurring in the scroll outer ring portion can be absorbed by the curved portion with low stress.
[0012]
Furthermore, a hollow cylindrical ring plate for connecting the male member and the scroll inner ring portion is provided, and the inner end portion of the male member is sandwiched by the ring plate so as to be slidable in the radial direction, and the scroll is scrolled to the ring plate A part of the inner ring is sandwiched. With this configuration, one part of the fitting (inner end portion of the male member) can be supported freely in the radial direction, the fitting can be prevented from being biased, and no gap can be formed in the fitting portion.
[0013]
Moreover, it is preferable that the said inner periphery fitting part consists of a female member which has an axial direction clearance gap, and a male member which fits in this clearance gap. With this configuration, it is possible to easily connect the outer periphery fitting portion and the inner periphery fitting portion only by moving the scroll outer ring portion in the axial direction together with the outer periphery fitting portion.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and used for the common part in each figure.
FIG. 1 is a structural view of a scroll seal according to the present invention. This figure is a partial cross-sectional view including the combustor 2 and shows a partial cross-section of the hollow rotating body centered on the engine axis ZZ located below the figure. In this figure, a scroll chamber 10 is configured to have a hollow donut-shaped scroll outer ring portion 10a disposed so as to surround a turbine shaft (not shown), and a radially inner passage area is small, and an inner peripheral end is a turbine. The scroll inner ring portion 10b is open to the blade row, and the scroll outer ring portion 10a and the scroll inner ring portion 10b are connected by the outer peripheral fitting portion 12 and the inner peripheral fitting portion 14.
[0015]
The outer periphery fitting portion 12 includes a female member 12a having an axial gap at a position away from the scroll outer ring portion 10a, and a male member 12b fitted into the gap at a position away from the scroll inner ring portion 10b. Moreover, the inner periphery fitting part 14 consists of the female member 14a which has an axial direction clearance gap, and the male member 14b fitted to this clearance gap, and these female member 14a and the male member 14b are the scroll outer ring part 10a. It is formed continuously at the connecting end of the scroll inner ring portion 10b. With this configuration, the outer periphery fitting portion 12 and the inner periphery fitting portion 14 can be easily connected together with the outer periphery fitting portion 12 only by moving the scroll outer ring portion 10a in the axial direction.
[0016]
The female member 12a of the outer periphery fitting portion 12 has an inward extending portion 13a extending radially inward, and the inner end of the inward extending portion 13a is fixed to the scroll outer ring portion 10a. The inward extending portion 13a of the female member 12a has a curved portion that is curved in the axial direction. With this configuration, the thermal deformation occurring in the scroll outer ring portion 10a can be absorbed by the curved portion with low stress.
[0017]
The inner end portion of the male member 12b of the outer periphery fitting portion 12 is attached to the scroll inner ring portion 10b so as to be slidable in the radial direction. That is, in this embodiment, the scroll seal structure of the present invention further includes a hollow cylindrical ring plate 16 that connects the male member 12b and the scroll inner ring portion 10b, and the inner end portion of the male member 12b is a ring plate. 16 is slidably held in the radial direction, and a part of the scroll inner ring portion 10 b is held between the ring plates 16. With this configuration, one part of the fitting (the inner end of the male member 12b) is supported freely in the radial direction, so that the fitting is prevented from being biased and no gap is formed in the fitting part.
[0018]
In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.
[0019]
【The invention's effect】
According to the configuration of the present invention described above, the scroll outer ring portion 10a and the scroll inner ring portion 10b are connected by the outer periphery fitting portion 12 and the inner periphery fitting portion 14, and the outer periphery fitting portion 12 is outside the scroll. Since it is connected by the female member 12a and the male member 12b that are located away from the ring portion, the entire fitting portion is directly exposed to the combustion gas 4 in the low temperature portion that is separated from the scroll main bodies 10a and 10b of the high temperature portion. Therefore, thermal deformation does not occur in the fitting portion for sealing. Further, with this configuration, since the fitting portion is located at a position separated from the scroll main bodies 10a and 10b, a wide degree of freedom can be obtained in designing the shape of the scroll main body and the position of the combustor.
[0020]
Therefore, the gap of the fitting part for sealing can be reduced, and since the thermal deformation is suppressed, the small gap can be maintained for a long time, and the entire fitting part is in the low temperature part. Design is easy and accurate.
[0021]
That is, the scroll seal structure in the gas turbine of the present invention is capable of maintaining a sufficient sealing performance without causing a gap in the fitting portion with low stress while being exposed to a temperature difference and a pressure difference. It has excellent effects such as the ability to keep the direction length short.
[Brief description of the drawings]
FIG. 1 is a structural diagram of a scroll seal according to the present invention.
FIG. 2 is an overall configuration diagram of a gas turbine.
FIG. 3 is a structure diagram of a conventional scroll seal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air compressor 2 Combustor 3 Turbine 4 Combustion gas 5 Scroll chamber 5a Front rear edge part 5b Rear front edge part 6 Flange 10 Scroll chamber 10a Scroll outer ring part 10b Scroll inner ring part 12 Outer periphery fitting part 12a Female member 12b Male member 13a Inwardly projecting portion 14 Inner peripheral fitting portion 14a Female member 14b Male member 16 Ring plate

Claims (3)

A scroll chamber comprising a hollow donut-shaped scroll outer ring portion that surrounds the turbine shaft, and a scroll inner ring portion that has a small radial inner passage area and an inner peripheral end that opens to the turbine blade row. In a gas turbine with
The scroll outer ring portion and the scroll inner ring portion are connected by the outer periphery fitting portion and the inner periphery fitting portion, and the outer periphery fitting portion has a female member having an axial clearance at a position away from the scroll outer ring portion. And a male member that fits into the gap at a position away from the scroll inner ring,
The female member has an inward extending portion extending radially inward, and an inner end of the inward extending portion is fixed to a scroll outer ring portion, and the inner end portion of the male member is an inner end portion of the scroll inner ring. A scroll seal structure in a gas turbine, wherein the scroll seal structure is slidably attached to the portion in the radial direction. 2. The scroll seal structure for a gas turbine according to claim 1, wherein the inward projecting portion of the female member has a curved portion curved in the axial direction. Furthermore, a hollow cylindrical ring plate for connecting the male member and the scroll inner ring portion is provided, and the inner end portion of the male member is sandwiched by the ring plate so as to be slidable in the radial direction, and the scroll is scrolled to the ring plate. The scroll seal structure for a gas turbine according to claim 1, wherein a part of the inner ring portion is sandwiched.

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