JP3631898B2 - Cooling structure of split ring in gas turbine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling structure for a split ring disposed on a radially outer peripheral side of a moving blade in a gas turbine.
[0002]
[Prior art]
As shown schematically in FIG. 7, the overall configuration of the gas turbine is that air is compressed by a compressor 1, fuel is injected into the combustor 2 to generate combustion gas, and the combustion gas is used as a mainstream gas. It introduce | transduces into the turbine 3, and the generator 4 is rotated.
[0003]
As shown in FIG. 8, the turbine 3 is composed of a plurality of rows of stationary blades 5 and moving blades 6 arranged alternately, and the outer peripheral side of the moving blade 6 in the radial direction is a hot gas. In order to send the rotor blade 6 to the downstream side with an appropriate gap, the structure is surrounded by a split ring (ring segment or chip seal segment) 10 having a plurality of split numbers in the circumferential direction.
[0004]
The split ring 10 has a cooling structure that can withstand the high-temperature mainstream gas 15 coming out of the combustor 2. An example of the split ring 10 having this cooling structure in a conventional gas turbine is shown in FIGS. This will be described with reference to FIG.
[0005]
The cooling medium 9 extracted from the compressor 1 or the cooling medium 9 supplied from an appropriate supply source provided outside is supplied to the cavity 16 through the impingement cooling plate 12 in which the impingement cooling port 11 is formed, and the divided ring. Then, the ring 10 is cooled again through a cooling passage 13 provided in the split ring 10, and discharged from the rear part 14 of the split ring into the mainstream gas 15.
[0006]
Here, the cooling passage 13 may have a circular, rectangular, or wavy cross section, and the cooling passage 13 is configured by arranging a plurality of axially extending holes in a substantially parallel circumferential direction. Yes.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional one, the cooling medium 9 needs to keep the cavity 16 higher than the pressure of the mainstream gas 15 in order to prevent the backflow of the high-temperature mainstream gas 15. The cooling medium 9 is supplied with the cavity 16 at a pressure relatively higher than that of the mainstream gas 15 on the upstream side in the axial direction.
[0008]
On the other hand, since the pressure of the mainstream gas 15 is lower on the downstream side in the axial direction than on the upstream side in the axial direction, the cavity 16 whose pressure is adjusted in relation to the mainstream gas 15 on the upstream side in the axial direction as described above. The inner cooling medium 9 consumes excessive leakage, leading to a decrease in turbine efficiency.
[0009]
Further, the cooling medium 9 in the cooling passage 13 is heated up as it goes downstream in the axial direction due to heat exchange by cooling, and the cooling performance decreases because the temperature rises considerably on the downstream side of the split ring. To do.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling structure that eliminates the above-described disadvantages of the prior art and improves the cooling efficiency of a split ring of a gas turbine.
[0011]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems, and is divided between the split ring and the impingement cooling plate disposed on the outer periphery thereof in the axial direction by a pressure partition plate extending in the circumferential direction, and adjusted to different pressures. The upstream cavity and the downstream cavity are provided , the inside of the upstream cavity opens through the cooling passage to the upstream half of the rotor blade tip, and the inside of the downstream cavity passes through the other cooling passage in the axial direction. The cooling structure of the split ring in the gas turbine that extends in parallel with the gas turbine and opens to the wake of the rotor blade is provided.
[0012]
That is, according to the present invention, the upstream cavity and the downstream cavity partitioned in the axial direction by the pressure separator are adjusted to different pressures, respectively, so that the mainstream gas having different pressures upstream and downstream in the axial direction can be individually controlled. In addition, the mainstream gas is prevented from flowing backward on the upstream side, and the leakage air from the gap is minimized on the downstream side to improve efficiency.
[0014]
In addition, the interior of the upstream cavity opens through the cooling passage to the upstream half of the blade tip, and the interior of the downstream cavity extends in parallel to the axial direction through the other cooling passage to the rear of the blade. Since it opens to the blade tip side at different positions in the axial direction by opening in the flow, the distance of the split ring cooling hole from the exit from each cavity to the blade tip side is shortened Especially, in the cooling passage from the upstream cavity, the cooling medium is released to the tip of the rotor blade before it warms up, so that the cooling effect of the rotor blade is enhanced , and in the other cooling passage from the downstream cavity, it is axially a shall enhance the cooling effect of the split ring by guiding a cooling medium extends in parallel form.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
Note that the same parts as those of the above-described conventional one are denoted by the same reference numerals in the drawings, and redundant description will be omitted as much as possible, and points unique to the present embodiment will be mainly described.
[0016]
Reference numeral 10 denotes a split ring, which is arranged close to the tip of the rotor blade so as to seal a gap with the tip of the rotor blade. In FIGS. 1 and 2, one of the parts divided in the circumferential direction is representative. Shown extracted.
[0017]
Reference numeral 12 denotes an impingement cooling plate, which is supported by a heat shield ring 19 so as to be concentrically arranged on the outer peripheral side of the split ring 10 at an appropriate interval with respect to the split ring 10, and is provided in a large number on the plate surface. A cavity for receiving a cooling medium is formed between the split ring 10 and the impingement cooling port 11.
[0018]
Reference numeral 18 denotes a groove provided on the surface of the split ring 10 so as to extend in the circumferential direction. A pressure separator plate 17 whose top surface is in contact with the impingement cooling plate 12 is fitted into the groove 18. A cavity formed between the impingement cooling plate 12 is divided into an upstream cavity 16a and a downstream cavity 16b.
[0019]
In addition, the pressure separator 17 may be divided into a plurality of parts in the circumferential direction, like the split ring 10 and the impingement cooling plate 12, and in this case, the circumferential joint has a small gap. The end faces may be joined to leave a minute leak, but the end joint faces may be cut into each other in the cross-sectional direction as shown in FIG.
[0020]
Further, as described above, the inner peripheral side of the pressure separator 17 is fitted with the groove 18, and the outer peripheral side facing this is an inverted L shape as shown in FIG. Of course, the shape is not limited, and other shapes such as a T-shape may be selected.
[0021]
The inside of the upstream cavity 16a opens to the range of the upstream half of the tip of the moving blade 6 through the cooling passage 13a, and the inside of the downstream cavity 16b extends almost parallel to the axial direction through the cooling passage 13b. Therefore, the distance between the cooling passages 13a and 13b is sufficiently shorter than the axial lengths of the split ring 10 and the tip of the moving blade 6.
[0023]
The impingement cooling plate 12 of each of the upstream cavity 16a and the downstream cavity 16b is provided with a large number of impingement cooling ports 11, but the impingement cooling port 11 opening to the upstream cavity 16a and the downstream The impingement cooling port 11 that opens to the side cavity 16b is different from each other in the size, shape, and numerical aperture of the opening diameter. The pressure in the upstream cavity 16a is higher than that in the downstream cavity 16b. The pressure in the upstream cavity 16a is adjusted to exceed the upstream mainstream gas 15a, and the pressure in the downstream cavity 16b is adjusted to exceed the downstream mainstream gas 15b.
[0024]
Since the present embodiment is configured as described above, the cooling medium 9 passes through the impingement hole 11 of the impingement cooling plate 12, and the split ring 10 that forms the upstream cavity 16a and the downstream cavity 16b is impinged. After being cooled, the split ring 10 is cooled again by passing through a plurality of rows of split ring cooling passages 13 a and 13 b extending in the axial direction, and finally discharged into the mainstream gas 15.
[0025]
The pressure of the cooling medium 9 supplied into the upstream cavity 16a and the downstream cavity 16b constituting the split ring cooling structure adjusts the size, shape, numerical aperture, etc. of the opening diameter of the impingement cooling port 11. Thus, as described above, the pressure in the upstream cavity 16a is relatively slightly higher than the pressure of the upstream combustion gas 15a, and the pressure in the downstream cavity 16b is slightly higher than the pressure of the downstream combustion gas 15b in which the pressure has decreased. As a result, the upstream cavity 16a of the split ring 10 has no fear of backflow of the mainstream combustion gas 15a, and the downstream cavity 16b minimizes leakage air from the gaps between the respective parts. It can be kept in.
[0026]
The cooling ring 9 is cooled by guiding the cooling medium 9 from the upstream cavity 16a and the downstream cavity 16b through the cooling passages 13a and 13b provided through the plate thickness of the split ring 10, and The cooling effect of the turbine blade 6 can also be expected by blowing this cooling medium 9 toward the tip of the turbine blade 6.
[0027]
Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to this embodiment, and it goes without saying that various modifications may be made to the specific structure within the scope of the present invention. Absent.
[0028]
For example, in the above-described embodiment, a single partition wall 17 is disposed between the impingement cooling plate 12 and the split ring 10 and divided into an upstream cavity 16a and a downstream cavity 16b. Of course, a plurality of cavities may be formed by partitioning with a plurality of partition walls 17.
[0029]
【The invention's effect】
As described above, according to the present invention, the upstream cavity and the downstream cavity that are divided in the axial direction by the pressure partition plate extending in the circumferential direction between the split ring and the impingement cooling plate disposed on the outer periphery thereof, and adjusted to different pressures, respectively. Since the cooling structure of the split ring in the gas turbine is configured, the cavities partitioned upstream and downstream in the axial direction by the pressure separators are adjusted to different pressures so that the mainstream gas having different pressures is adjusted. It was possible to deal with each individually and appropriately, and the upstream side prevented the backflow of the mainstream gas, and the downstream side was able to further improve the efficiency of the gas turbine by minimizing the leaked air from the gap.
[0030]
In addition , according to the present invention, the interior of the upstream cavity opens through the cooling passage to the upstream half of the blade tip, and the interior of the downstream cavity passes through the other cooling passage and is parallel to the axial direction. Since it extends to open to the wake of the rotor blade and opens to the tip of the rotor blade at different positions in the axial direction, it forms a cooling structure for the split ring in the gas turbine. ring segment cooling hole opened to blade tip side at different positions in the axial direction, the distance ring segment cooling hole from exiting the respective cavity until the opened toward the rotor blade tip side is shortened, especially the upstream In the cooling passage from the side cavity, the cooling medium is released to the tip of the rotor blade before it warms up, so the tip of the rotor blade is film cooled, and in the other cooling passage from the downstream cavity, it is parallel to the axial direction. Extending into the cooling medium Sufficiently cool the split ring by the guide to one in which it was possible to further improve the gas turbine cooling efficiency together.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view showing a cooling structure for a split ring in a gas turbine according to an embodiment of the present invention.
FIG. 2 is a side sectional view of a cooling structure of a split ring according to the present embodiment.
FIG. 3 is an explanatory view showing cavity division by a pressure separator, which is a main part of the cooling structure of the split ring of the present embodiment.
4 is an explanatory view showing a joining state of a divided portion of the pressure diaphragm shown in FIG. 3; FIG.
FIG. 5 is a perspective view showing a cooling structure of a split ring in a conventional gas turbine with a part broken away.
FIG. 6 is a side sectional view of a conventional cooling structure for a split ring.
FIG. 7 is an explanatory diagram schematically showing an overall configuration of a gas turbine.
FIG. 8 is an explanatory diagram schematically showing a general configuration of a turbine section.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor 2 Combustor 3 Turbine 4 Generator 5 Stator blade 6 Rotor blade 9 Cooling medium 10 Split ring 11 Impingement cooling port 12 Impingement cooling plate 13 Cooling passage 14 Split ring rear portion 13a Cooling passage 13b Cooling passage 15 Main flow gas 15a Upstream side mainstream gas 15b Downstream side mainstream gas 16 Cavity 16a Upstream side cavity 16b Downstream side cavity 17 Pressure separator 18 Groove 19 Heat shield ring

Claims (1)

An upstream cavity and a downstream cavity that are divided in the axial direction by a pressure partition plate extending in the circumferential direction between the split ring and an impingement cooling plate disposed on the outer periphery thereof, and adjusted to different pressures are provided , and the upstream cavity The inside of the cavities opens through the cooling passage to the upstream half of the blade tip, and the interior of the downstream cavities extends parallel to the axial direction through the other cooling passage and opens to the wake of the blade . A cooling structure for a split ring in a gas turbine.

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