JPH1136811A - Cooling steam distribution mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an efficiency of a gas turbine by restraining the occurrence of unnecessary thermal stress, feeding and distributing cooling steam more smoothly when cooling steam is distributed to the stationary blades and divided rings of the gas turbine. SOLUTION: A cooling steam distribution mechanism is so constituted that each clearance between the stationary blade row and the divided ring row of a gas turbine is crosslinked with a mother pipe which is divided into plural numbers in the circumferential direction, that is to say, the mother pipe provided for each clearance between the stationary blade row and the divided ring row, divides the restriction of a related pipe line group, not as the single mother pipe for the entire circumference, but as a plurality of the divided mother pipes, so as to allow the effect of thermal stress to be made small, and also to allow the degree of freedom in design, manufacture, assembly and the like to be high, so that the aforesaid mechanism thereby contributes much to the enhancement of an efficiency of the gas turbine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cooling steam distribution mechanism for distributing cooling steam to stationary blades and split rings of a gas turbine.

[0002]

2. Description of the Related Art A conventional device will be described with reference to FIG.
In a gas turbine, it has been proposed to cool a split ring disposed at a position where an outer diameter of a turbine vane and a moving blade of a gas flow path wall are opposed to each other with steam.

[0003] In this case, the cooling steam is flowed in a so-called parallel connection in which each of the stationary blades and the split ring are connected to a supply pipe and a recovery pipe, respectively, and the steam discharged from the first-stage stationary blade is divided into a split ring in its own row. Supply, and then flow through all stages in the same manner,
There is a series connection that is recovered in the last stage, and a method that combines both parallel and series.

[0004] Fig. 2 shows a type belonging to the series connection, in which steam introduced from a steam supply pipe 21 is supplied from a branch pipe 22 to a first stage vane 23, and after exiting the first stage vane 23, a branch pipe. 24, and is supplied to a first-stage split ring 26 via a mother pipe 25.

[0005] Next, the cooling steam flowing out of the first-stage split ring 26 flows through the second-stage split ring through the second-stage stationary blades, branch pipes, and the mother pipe similarly to the first stage, and is collected in the steam recovery pipe 27. And collected.

[0006] The number of blades for one row of stationary blades in each stage of the turbine is determined in each stage so as to be optimal in terms of performance. In addition, the circumference of the ring is also divided into an appropriate number from the viewpoint of reducing thermal stress and strain. That is, the optimal values of the number of vanes and the number of divisions of the split ring are different for each paragraph.

[0007]

As described above, the number of blades for one row of stationary blades and the number of divisions of the split ring in each paragraph are independently set according to the circumstances of each paragraph, and are divided into different numbers. However, the supplied cooling steam must be piped such that it is equally distributed to each individual in the same row.

As a normal basic pipe, a mother pipe is provided in an annular shape on the inlet side of the first paragraph and on the outlet side of the last paragraph.
A branch pipe is provided from the mother pipe to each of the stator blades at the first stage and from each of the split rings at the last paragraph to the mother pipe.

At the same time, a main pipe is provided between the respective paragraphs, and the recovered steam of the previous stage is once collected in the main pipe between the paragraphs, and the branch pipe is communicated from the main pipe to each of the following paragraphs. To supply cooling steam.

In such a pipe, a large number of pipes must be arranged in a limited space so that thermal stress is kept as small as possible, and assembly and disassembly can be easily performed during production and maintenance. There is a request not to.

Under such a background, the present invention provides a cooling steam distribution mechanism which supplies and distributes the cooling steam more smoothly under the concept of the basic piping and contributes to the improvement of the efficiency of the gas turbine. The task is to provide.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and comprises a plurality of circumferentially divided mother pipes connecting a stationary blade row and a divided ring row of a gas turbine. The present invention provides a cooling steam distribution mechanism.

In other words, the main pipe provided between the stationary blade row and the split ring row of the gas turbine is not a single main pipe on the entire circumference but a plurality of divided main pipes. The restraint is broken, the influence of thermal stress is reduced, and the degree of freedom in design, manufacture, assembly, etc. is increased.

Further, according to the present invention, the number of divisions of the mother pipe is set to the greatest common divisor of the number of front and rear stationary blades and division rings, and the minimum cross-sectional area for equalizing the output flow at a plurality of outlets of the mother pipe is provided. The present invention provides a cooling steam distribution mechanism.

That is, when the mother pipe is divided,
Considering the number of downstream stationary vanes or split rings, the greatest common divisor is used as the number of divided pipes to improve the input / output balance between the inlet side and the outlet side flowing into the pipe. By selecting the cross-sectional area of such a size that a uniform output flow rate can be obtained at a plurality of outlets communicating with one mother pipe, the overall flow balance is kept good from this aspect as well. is there.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a divisional arrangement of equipment and a communication relationship of cooling steam in a half (180 °) in a circumferential direction of a first paragraph and a second paragraph in the present embodiment. FIG. 1 is a schematic diagram of a geometric pattern pattern developed and developed on a plane.

Reference numerals are given as representatives of those at the top of the drawing, but the same members are arranged in each row, 1 is a first stage stationary blade, 2 is a first stage split ring, 3 is a second stage stationary blade, Reference numeral 4 denotes a second-stage split ring, and 6 denotes a first-stage stationary blade 1 and a first-stage split ring 2.
, A reference numeral 7 denotes a parent pipe between the first stage split ring 2 and the second stage stationary blade 3, and a reference numeral 8 denotes a parent pipe between the second stage stationary blade 3 and the second stage split ring 4.

Reference numeral 5 denotes a cooling steam supply pipe which is arranged on the steam supply side upstream of the first stage stationary blade 1 and supplies cooling steam to the first stage stationary blade 1. Reference numeral 9 denotes a steam recovery side downstream of the second stage split ring 4. And a cooling steam recovery pipe that collects and collects the steam of the second-stage split ring 4.

In this embodiment having such an arrangement,
Now, from the design conditions, the number of blades of the first stage stationary blade 1 is 32, the number of divisions of the first stage split ring 2 is 48, the number of blades of the second stage stationary blade 3 is 36,
The number of divisions of the second-stage split ring 4 is 48.

Therefore, in FIG.
Since 0 ° is indicated by a circle in a geometric pattern, there are 16 circles corresponding to the first stage stationary blade 1 and the first stage split ring 2.
24, 18 corresponding to the second stage stationary blade 3, and 24 corresponding to the second stage split ring 4.
Are shown.

Next, regarding each of the mother pipes 6, 7, and 8 disposed between the stator vane and the split ring, each mother pipe has the greatest common divisor of the number of the upstream and downstream stator vanes and the split ring. It is divided into a corresponding number of divisions.

In other words, the mother tube 6 has a first stage stationary blade 1 of 32 upstream.
Since the number of the first-stage split rings 2 on the downstream side is 48, the greatest common divisor is divided into 16 (in the drawing, half of the 8 pieces are represented by an elliptical geometric pattern. The same applies to the pipes 7 and 8), and the mother pipe 7 has 48 upstream first-stage split rings 2 and 36 downstream second-stage stationary vanes 3, so that its greatest common divisor is 1
The mother tube 8 is divided into 36
Since the number of the downstream second stage split rings 4 is 48, the maximum common divisor thereof is divided into twelve.

In the present embodiment thus configured, the cooling steam supplied from the cooling steam supply pipe 5 to the first stage stationary blade 1 by a branch pipe (not shown) cools the inside of the blade, As shown by the parallel arrows, a flow rate corresponding to each of the two stationary blades flows into the mother pipe 6, flows from the mother pipe 6 for three minutes, and flows out to the first-stage split ring 2.

Next, the mother pipe 7 receives cooling steam corresponding to four of the upstream first-stage split rings 2 and supplies the cooling steam to each of the three downstream second-stage stationary blades 3 for supply. In the mother pipe 8, cooling steam is supplied from the three upstream second-stage stationary blades 3 in a three-way stream, is supplied to the downstream second-stage segmented ring 4 by being divided into four streams, and finally from each second-stage segmented ring 4. It is collected in the cooling steam recovery pipe 9 by a branch pipe not shown.

As described above, each of the mother pipes 6, 7, 8 is determined by the greatest common divisor of the upstream stationary vane or the split ring and the downstream of the respective stator pipes. 6,
7 and 8, when viewed in units of rows, the inflow and outflow conditions of each divided body are equal, and the flow in the circumferential direction is balanced.

Further, since the upstream and downstream stator blades or split rings of the respective mother tubes 6, 7, and 8 have different numbers of divisions, the numbers of inlets and outlets of the cooling steam are different from each other. Causes the output flow rate at each outlet to fluctuate.However, by making the cross-sectional area of the mother pipe a constant size determined by each design condition, the occurrence of this variation is suppressed and each output flow rate becomes uniform. And so on.

As described above, according to the present embodiment, the mother pipes 6, 7, 8 for distributing and collecting the cooling steam are divided in the circumferential direction in balance with the front and rear devices, so that the thermal stress in the circumferential direction can be reduced. The cooling steam is made to be small and the flow of the cooling steam is made stable, so that a suitable cooling steam distribution structure which is easy to assemble and disassemble is obtained.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to such an embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0030]

As described above, according to the present invention, the cooling steam distribution mechanism is constructed by connecting the stator blade row and the split ring row of the gas turbine with a plurality of circumferentially divided mother pipes. The main pipe provided between the gas turbine vane row and the split ring row is not a single main pipe on the entire circumference, but is divided into a plurality of main pipes. In addition, the influence of thermal stress can be reduced, the degree of freedom in designing, manufacturing, assembling, etc. can be increased, and the efficiency of the gas turbine can be greatly improved.

According to the second aspect of the present invention, the number of divisions of the mother pipe is made the greatest common divisor of the number of front and rear stationary blades and split rings, and the output flow rate is made uniform at a plurality of outlets of the mother pipe. By setting the minimum cross-sectional area, the input-output balance between the inlet side and the outlet side flowing into the main pipe is improved, and the cross-sectional area of the main pipe is evenly distributed to a plurality of outlets communicating with one main pipe. By selecting the output flow rate to be large enough, the balance of the entire flow can be kept good from this aspect as well, and it can greatly contribute to the improvement of the efficiency of the gas turbine as described above.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a divided structure of a mother pipe for distributing cooling steam according to an embodiment of the present invention, which is developed in a geometric shape.

FIG. 2 is an explanatory diagram showing an arrangement structure of a stationary blade, a split ring, and the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st stage stationary blade 2 1st stage division ring 3 2nd stage stationary blade 4 2nd stage division ring 5 Cooling steam supply pipe 6, 7, 8 Main pipe 9 Cooling steam recovery pipe

Claims (2)

[Claims] 1. A cooling steam distribution mechanism, wherein a stationary blade row and a divided ring row of a gas turbine are connected by a plurality of circumferentially divided mother tubes. 2. The method according to claim 1, wherein the number of divisions of the mother pipe is a greatest common divisor of the number of front and rear stationary blades and division rings, and a minimum sectional area for equalizing an output flow at a plurality of outlets of the mother pipe. The cooling steam distribution mechanism according to claim 1, wherein: