JPS6035103A - Steam turbine rotor cooling equipment - Google Patents

Abstract

PURPOSE:To efficiently cool a turbine blade implanting part by providing a blade in the first stage and both a nozzle and a blade in the second stage and thereafter with a partition that separates each steam passage in the radial direction and supplying cooling steam through the inner flow passage while supplying principal steam through the outer passage respectively. CONSTITUTION:Principal steam of high temperature FH flows into an upper part nozzle box 3a via a principal steam feeding pipe 11, flows in a flow passage on the tip side (outward in the radial directin) with respect to a partition 15a in a flow passage of a blade 6 in the first stage via a principal steam nozzle 4a, and then flows into a nozzle 13 in the second stage, while giving turning effort to a rotor 2. On the other hand, cooling steam FC flows into a lower part nozzle box 3b via a cooling steam feeding pipe 12 and flows out into a flow passage on the root side with respect to the partition 15a in the flow passage of the blade 6 in the first stage via a cooling steam nozzle 4b. With this contrivance, both the implanting part of the blade 6 and the rotor 2 are brought into contact with the cooling steam FC that is lower in temperature than the principal steam FH so that they can be cooled efficiently.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a steam turbine rotor cooling system that can effectively cool the blade implants, rotor, etc. without impairing the performance of the turbine. Regarding.

[Technical background of the invention and its problems] Recently, steam turbines have become larger in capacity.

It is becoming common for steam turbines to be used under high-temperature, high-pressure steam conditions, and in particular, increasing the temperature and pressure of the incoming steam to a steam turbine greatly contributes to the overall turbine power plant, so it is necessary to maintain high reliability while maintaining high reliability. The demand for higher temperatures and higher pressures in turbines is likely to grow stronger in the future.

Normally, in a large-capacity steam turbine, the steam that has performed work in the high-pressure turbine is extracted, returned to the boiler, and reheated in a reheater, and this reheated steam is further supplied to the intermediate-pressure turbine to perform work. cycle is used. Therefore, in order to raise the temperature of the steam flowing into the turbine, it is necessary to solve various problems regarding the material strength of the rotor and casing used in the high-pressure stage and intermediate-pressure stage at high temperatures.

In particular, the rotor may bend due to creep during rotation at high temperatures, which may cause rotor vibration.

I ~ Therefore, this prevents the rotor bending phenomenon by +1
- In order to achieve
'1.

By the way, even with this 120r copper rotor.

In order to make the inflow steam temperature higher than 566C, which is currently widely adopted, it is necessary to forcibly cool the rotor from the outside by some method.

In addition, the 5-blade implanted area is a part where large stress is locally generated, and it is difficult to cool it because it is constantly heated by wide steam. To achieve this, it is necessary to effectively cool the blade implant.

In other words, Figure 1 shows the first stage in a typical steam turbine.
It is a longitudinal partial view showing a paragraph part, and steam supplied from the boiler via a control valve flows into a nozzle box 8 disposed between the internal casing 1 and the rotor 2 at its axial center position, It flows out from the nozzle 4 formed at the outlet of the nozzle box 8, passes through the passage of the blade 6 installed in the wheel 5 integrated with the rotor 2, performs the i4i work, and rotates the rotor 2. Thereafter, it flows out from the blade 6 and flows into the next stage nozzle.

However, a part of the high-ugliness, high-pressure steam that flowed out from the nozzle 4 is as shown by arrow F in FIG.

Tonal leaks from the gap between the nozzle 4 and the wheel 5, stagnates between the rotor 2 and the nozzle box 8, and heats the nozzle box 8 and the rotor 2. In addition, the high-temperature steam flowing into the blades 6 from the nozzle 4 completely heats the implanted part where the blades 6 are installed in the wheel 5, and this heat is transmitted to the rotor 2 by thermal conduction, heating the rotor 2, and while the rotor is rotating. Creep occurs and bending occurs, causing rotor vibration.

Therefore, in order to further increase the steam temperature and improve plant performance while maintaining current reliability, it is necessary to effectively cool the blade implants and rotor.

[Purpose of the invention]

In view of these points, the present invention effectively cools the blade implants and rotor without compromising turbine efficiency, thereby operating the turbine at high steam temperatures while maintaining reliability.
I made it possible to turn it around. The purpose is to obtain an N turbine rotor cooling device.

[Summary of the invention]

The present invention forms a first stage nozzle of a steam turbine by a main steam nozzle section through which main steam flows out, and a cooling steam nozzle section through which cooling steam having a lower filling rate flows out. The blades of the stage and the nozzles and blades of the second and subsequent stages are each provided with a partition wall that divides the passage into at least two in the radial direction, and the cooling steam is allowed to flow through the innermost passage in the radial direction, and into the other passages. The main steam is made to flow, and the a-evening part is effectively cooled by the cooling steam,
This is designed to reduce the increase in WA degree in that part.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 to 5.

FIG. 2 is a vertical cross-sectional view 1 showing the high-pressure stage section of a steam turbine, in which the inner casing 1 and the a-
A nozzle box 8 is provided between the holder 2 and the holder 2. As shown in FIG. 3, the nozzle box 3 is divided into upper and lower halves on a horizontal plane, and is composed of an upper nozzle box 8a and a lower nozzle box 8b, with a support member 10 interposed between the two nozzle boxes 8a and Bb. For example, 5 to 3 (l w
A space of about I+ is formed and they are connected and fixed to each other.

A main steam supply pipe 11 is connected to the upper nozzle box 3a, and also to the part facing the blades 6 of the first stage.

The main steam nozzle 4a is provided in a semicircular shape so that the main steam FH flows out toward the tip side of the blade 6.

On the other hand, in the lower nozzle box 3b.

A cooling steam supply pipe 12 that supplies cooling steam FQ at a temperature lower than that of the main steam is connected to the blade 6 of the first stage.
A cooling steam nozzle 4b is provided in a semicircular shape in a portion facing the blade 6 so that the cooling steam flows out toward the root side of the blade 6.

In addition, the first stage blade 6 attached to the tip of the wheel 5 that is integrally structured with the rotor 2, and the nozzle 13 and blade 14 in the second and subsequent stages have a steam flow path with a radially inner flow path and an outer flow path. A cylindrical partition wall 15a that divides into two.

15b and 15c are provided. The partition walls 15a, 1
5W and 15C, for example, are made of a 14-piece structure that increases the heat insulation effect by using a hollow member, reduces weight at the same time, and reduces centrifugal force in the partition walls provided on the blades to 1% and has sufficiently high reliability.

By the way, the root of the main steam nozzle 4a and the radial position of the tip are set to be equal to the partition wall 15a of the first stage blade 6 and the radial position of the tip. Partition walls 15a, 15b.

15c so as to flow through the outer flow path. It's 1.

The root of the cooling steam nozzle 4b and the radial position of the tip are the root of the first stage vane 6 and the radial position of the partition wall 15&! They are set to be equal (7) so that the cooling steam flows through the channels inside the partition walls 15a, 15b, and 15c.

Therefore, the high temperature main steam PH flows into the upper nozzle box 8a through the main steam supply pipe 11, passes through the main steam nozzle 4a, and is partitioned by a partition wall 15a in the flow path of the first stage blade 6. flows into the flow path on the chip side (radially outward),
It flows into the second stage nozzle 13 while applying rotational force to the rotor 2 . In the second and subsequent stages as well, the main steam performs work while flowing through the flow path outside the partition wall provided in the nozzle and the blade, respectively.

On the other hand, steam 1, which has a temperature approximately 10 to 300 degrees lower than the main steam and has a pressure 1-100 degrees lower than the main steam, for example, steam extracted from the middle of a superheater of a boiler, is used as cooling steam 11Q in the cooling steam supply pipe 12. The steam flows into the lower nozzle box 8b through the cooling steam nozzle 4b, and flows out into the route side flow path partitioned by the partition wall 15a in the flow path of the first stage vane 6.
2. Do your work there.

After that, pass the nozzle and blade in the next paragraph through the rice cake. Therefore, the blade implant and the rotor are in contact with cooling steam at a temperature lower than the main steam, and the rotor is effectively cooled by the cooling steam. Moreover, in this case, the cooling steam flow and the high-temperature main steam are separated by the partition wall, and the main steam is prevented from flowing toward the rotor, so the heating effect of the main steam on the rotor, etc. is reduced, and the above-mentioned The cooling effect of the rotor section is ensured.

Further, in this embodiment, the nozzle box includes an upper nozzle box that constitutes a nozzle box for main steam;
Since the nozzle pock 7 is divided into the lower nozzle pock 7 that constitutes the nozzle box for cooling steam, and a space is provided in between, the cooling steam is heated by the main steam while passing through the nozzle box, reducing the cooling effect. In addition, thermal stress on the nozzle box can be kept to a minimum.

FIGS. 4 and 5 are views showing other embodiments of the present invention, in which cooling steam flows out into the lower nozzle box 8b biased toward both the root side and the tip side of the blade 6 of the first stage. Cooling steam nozzle 16a.

16b are provided in two concentric rows, and the main steam nozzle 4a is arranged in the upper nozzle box 8a so that the main steam is concentrated in the radial center of the flow path of the first stage blade 6. is provided.

On the other hand, the feather 6 in the first paragraph. The cooling steam nozzle 1 is installed in the nozzle 13 and the blade 14 after the second stage of the downward direction, respectively.
A node-shaped space 117a corresponds to 6a and 16b.

17b, 18a, 18b, 19a, and 19b are provided to divide the steam passage into eight passages in the radial direction, with cooling steam flowing through the innermost passage and outermost passage, and main steam flowing through the intermediate passage. It's Nishide.

In this case, both the blade implantation part and the shroud part of the tip can be cooled and maintained at a temperature lower than the main steam temperature by the cooling steam.

In each of the above embodiments, the nozzle box is shown divided into upper and lower sections, but it is not necessary to divide the nozzle box into upper and lower sections, and it is of course possible to divide the nozzle box into left and right sections.

[Effects of the Invention] As explained above, the present invention comprises a first-stage nozzle, a main steam nozzle section through which main steam flows out, and a cooling steam nozzle section through which cooling steam having a lower hot water temperature flows out. At the same time, a partition wall is provided in the first stage vane and the second stage nozzle and vane, respectively, to divide the steam flow path into at least two in the radial direction, and the cooling steam is formed in the radially innermost flow path. Since the main steam is made to flow through other flow paths, cooling steam whose temperature is lower than that of the main steam always flows through the portion where one blade is installed and the portion along the rotor.

Regardless of whether the turbine is operated with high temperature main steam, The increase in ilf can be suppressed to a low level, the occurrence of rotor creep can be prevented, and the occurrence of vibration can be prevented. Moreover, since the cooling steam itself also performs work, the drop in efficiency is low.Furthermore, since the nozzle box is divided into a part with the main steam nozzle and a part with the cooling steam nozzle, the nozzle pock 7 receives a large amount of heat. The generation of stress can also be avoided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first stage part of a general steam turbine, FIG. 2 is a longitudinal sectional view showing the rotor cooling device i of the present invention, and FIG. 8 is the ml-III line in FIG. 2. 4 is a longitudinal sectional view showing another embodiment of the present invention, and FIG. 5 is a sectional view of a portion taken along line v-v3 in FIG. 4. 1... Internal casing, 2... Rotor, 8... Nozzle box, 8a... Upper nozzle pock x, 8o.
...Lower nozzle box, 4...Nozzle, 4a River main steam nozzle, 4a, +6a, 161)...Cooling steam nozzle, 6...1st paragraph vane* 15a, 15t
+, 15c, 17a. 17b, 18a, 18b, 19a, 19b river bulkhead. Applicant's agent Kiyoshi Inomata, 63rd, 4th

Claims (1)

[Scope of Claims] 1. The m11'f nozzle is formed by a main steam nozzle part through which main steam flows out, and a cooling steam nozzle part through which cooling steam having a low temperature rises. 1
For the blade of the paragraph and the nozzles and blades of the second and subsequent paragraphs,
A partition wall is provided which divides the steam flow path into at least two parts in the radial direction. Cooling steam is allowed to flow through the innermost flow path in the radial direction. A special feature of the steam turbine rotor cooling system is that the main steam is allowed to flow through other flow paths. 2. The steam turbine rotor cooling device according to claim 1, further comprising a main steam nozzle and a main steam nozzle. 8. The first stage vane and the second and subsequent stage nozzles and vanes are each provided with a partition wall that divides the flow path into eight in the radial direction, and cooling steam is supplied to the innermost flow path and the outermost flow path. Claim 1 (B) Steam having a diameter of ψ, characterized in that the main steam is made to flow completely through the central flow path.
Turbine rotor cooling system. A steam turbine rotor according to claim 2, characterized in that a gap is provided between a portion of the first stage nozzle nozzle provided with a cooling steam nozzle and a portion provided with a main steam nozzle. Part cooling device.