JPS58202301A - Cooling device of steam turbine rotor - Google Patents

Abstract

PURPOSE:To reduce stress of a rotor, by providing an axial flow compressor device to a space formed between the rotor and the internal surface of a nozzle box and flowing cooling steam, which flows in through a hole extended through a stationary blade, into the upstream of the rotor through pumping action of said axial flow compressor device. CONSTITUTION:A space S formed between a rotor 7 and the internal surface of a nozzle box 1 is communicated to a passage 22 extended through a stationary blade 2, and a screw seal 8 is provided to a surface of the rotor 7. Rotation of the rotor 7 causes pumping action of the screw seal 8, and cooling steam flowing in via the passage 22 is penetratively circulated to the upstream of the rotor 7. In this way, since the rotor 7 can be cooled without causing the necessity for forming an annular train of holes in a disc part of the rotor 7, the generation of concentrated stress due to the hole can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for a steam turbine rotor.
The present invention relates to a cooling device suitable for a steam turbine that cools the upstream side of a rotor using steam that has passed through the rotor.

In a steam turbine, it is desirable to use steam as the prime mover of thermodynamics as much as possible. On the other hand, the temperature of the palanquin and the rotor that supports it is limited to a temperature that can be safely used from the viewpoint of strength. Therefore, many devices for cooling the tIIJ blade and rotor have been proposed.

As is well known, a steam turbine is usually equipped with several successive expansion stages consisting of a pair of stator vanes and a pair of blades, and the steam flows upward.
As it passes each pi from the L side, its altitude and pressure are reduced. In order to effectively cool a particular stage, the cooling fluid (liquid or A) that must be injected into that stage must be lower than the energy passing through that stage and adversely affect the output. There must be n.

The cooling system fIItt can be roughly classified into three types depending on the means for obtaining a high-pressure cooling fluid reservoir.

First, a part of the main steam, which is the motive force, is branched off in front of the turbine inlet, cooled with hot steam, etc., and then injected into the stage tower to be cooled. The second method, as shown in Japanese Patent Publication No. 51-149734, is fL6, which is used for tanthermal air turbines on earth. Part of the steam from the heavy pressure turbine is extracted and this is used as cooling steam for the reheat turbine. This method is clumsy; the output of the steam is higher than the pressure of the reheating stage, and the configuration is conversely only used in low pigeon lofts.

The third type of cooling device, as shown in Japanese Patent Application Laid-Open No. 54-7005, is a type of cooling device in which the pressure of steam expanded after passing through a specific stage is increased and the steam is delivered to the upstream side for cooling.

Although the first and second types of cooling shears each have a favorable cooling effect on the rotating parts of the turbine, they have the disadvantage of requiring separate piping for distributing the first vemi cooling fluid. The disadvantage of the second system is that it cannot be applied to cooling high-pressure turbines.

On the other hand, the third cooling device 11. Summary 1. To overcome the drawbacks of the cooling device of the conduit 2 and to exhibit a more effective cooling effect.

This type of cooling r#c111 will be explained in more detail below.

According to the device shown in %S 1970-7005, the first expansion stage is attached to the steam turbine and is supported by the disc part of the rotor. In order to prepare for the darkness between the first and second seal iron naokuraen grudge parts and the silent storm, it is possible to minimize the leakage of Makoto A from the main steam flow path before P # 彊. 7-It is impossible to completely prevent leakage through the L-package, and this leakage "Aμ
The rotor structure, including the disk portion and the exciter/disc connection portion, will overheat. In order to overcome this overheated child,
An annular row of holes is provided in the rotor disc part, and -S of the steam expanded in the W41 expansion stage (Takumi released it once) is passed through these holes, and the darkness between the Keishinzaru and the disc part is removed. The liquid is injected using a pump action, and the pressure is increased sufficiently so that the high temperature seal part kPi pus is absorbed by light. A portion of the unexpanded steam leaking from the injected #aggressive cooling Aμ seal is placed and passed through a series of labyrinth seals along the rotor to minimize the AM of the rotor. Following this, the low pressure stage expands at the same temperature. In order to strictly suppress the inflow of air into the cooling air, the first and second sealing devices are formed in the darkness between the disk portion and the still air. Uninflated fish m from the seal space
lr: extracting device gold bias, the second sealing device is adapted to limit unexpanded vapor from entering the expanded cooling vapor from the sealing space.

This arrangement will have a favorable effect on the cooling of the rotor section of the first expansion stage where the steam temperature is highest; however, in order to provide a large number of annular rows of holes in the hot and stressed rotor circles, The disadvantage is that the stress caused by the holes causes significant stress in the mouth and nose.

From this point of view, the purpose of the present invention is to provide a passage for expanded cooling steam separately from the rotor, eliminate the annular row of holes in the disk portion of the rotor, while ensuring a sufficient cooling effect for the rotor.
It is an object of the present invention to provide a steam mabin rotor cooling system that reduces stress.

Briefly stated, according to the present invention, a hole is provided through the stator vane and the inside of the stator blade to serve as a passage for the expanded cooling air, and the space is narrowed toward the upstream side of the rotor. A hydraulic pressure ring device is installed in the space formed by the cabinet of the nozzle box and the cabinet of the nozzle box, which is placed in the same position as the nozzle box. It is a good idea to let it flow into the upstream side.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. 5#! Figure 1 shows the first high-pressure turbine of the steam turbine.
Delete the paragraph and part of the second paragraph. The Ml expansion stage 23, commonly called a W split membrane, is provided on the disk portion 18 of the rotor 7, as shown in Figure 1 UC, and an annular row of rotor blades 3 is installed around this ILC/J.
Attach by suitable means, such as wooden serrations. On the upstream side of the rotor blades 3, there is disposed an annular nozzle 6 having a 01 annular row of stator vanes 2, and the trench 6 is connected to an annular nozzle box 1 attached to the live steam mCA mortar 2. In the nozzle box IK-, a plurality of main steam pipes 19 corresponding to σJJfil are installed and penetrated outside the cage puffer (not shown), and then connected to the boiler (not shown).
The high temperature Takashi steam from is introduced into the nozzle box 1.

As is well known, the control stage 23's 1tb43 is of the fully active type and extracts considerable energy from the steam flow, so this step will result in a considerable power drop and a significant drop in the output.

In response to the movement X31 of the control stage 23, the Izuo steam flows radially outward, and then reverses its direction and passes around the main steam pipe 19 to the flow direction 4 of the second expansion stage 24. flows.

An annular shroud 9 is fixed to the tip of the rotor blade 3 of the control stage (first expansion stage) 23 with a tenon 10, so that all the rotor blades are connected to each other, and during operation, the tip of the rotor blade 3 and the stator blade ring 6 are Seal pieces 11 and 12 are provided on the face of the stator vane ring 6 facing the shroud 9 in order to restrict leakage of steam from the gap.

The seal 1 of the disc part 18 faces the buttons 20 and 21 - [
Seal pieces 13 and 14 are provided on the inner surface of the damper 6 to restrict a portion of the main steam flow from leaking as a leakage steam flow B before passing through the rotor blade 3' and expanding. . The sealing space P surrounded by the sealing piece 13.14 and the sealing surface 20.21 and the space J14!4 of the second expansion stage 24 are connected to each other by the passage 15 of the annular tarp penetrating the stator vane ring 6 and the nozzle box l. communicate.

The stationary blade 3jli6 is provided with an annular row of passages 16 in the axial direction,
The leakage space S formed by the innermost circumference 1f1 of the nozzle %1 and the outer circumference Cml of the rotor 7 and the commuter 16 are communicated by a plurality of passages 22 extending in the radial direction passing through the inside of the stator blade 2. . Good luck lol! 16 and the passage 22 and their relative relationship with the passage 15 are shown in FIG.
This is clearly shown in FIG. 2 when viewed in the direction of the arrow at It line break 1 [11.

o-Evening 7 leakage space St/CIfJt, to the clothes 1 button,
A screw seal 8r is provided, which is formed by a male screw that is oriented to advance the female screw to the left in the plane of the drawing in FIG. 1 by one revolution of the rotor. For example, Figure 3 only schematically shows the hood rotor 7 and screw knob 8, but the rotor rotates clockwise (i.e., rotational force 1 N) when viewed from the right side of the page.
A screw seal 8 having a direction like a square is provided.

The main steam flow is directed through the nozzle box 1 to the -C first expansion 0h [2] and the rotor blades 3, but most of it passes through the rotor blades 3 and is directed to the rotor 7'? to drive. A small amount of leaked steam flows from around the shroud 90 through the seal pieces 11 and 12 and returns to the main steam tttt. I'll be with A. A part of the unexpanded steam that passes through the static X2 and enters the dynamic N3 becomes a leaked steam flow B, passes through the 7-channel piece 13, and flows into the air passage P, but the sealed space P is The second expansion stage 24 is in direct communication with the 40 population, and the seal piece 14 is connected to the leakage space S.
Since the flow of \ is restricted, most of the steam passes through passage 15 and joins the main steam flow man again.

During operation, the rotation of the rotor 7 causes a pumping action of the threaded seal 8, and a flow shown by an arrow C is created in the leakage space S.

This flow results in a continuous flow of steam (and thus of reduced temperature and pressure) entering via passages 16 and 22 communicating the leakage space S with the outlet of the first expansion stage IR3. Therefore, the steam flow that is sucked and flows into the leakage space S'ftrx by the pump action of the screw seal 8 becomes a continuous cooling steam flow C of expanded and cooled steam, and effectively cools Ijj on the upstream side of the rotor. However, it will be appreciated that the heat extracted during that time can be transferred to the a2 expansion stage 24.

According to this embodiment, the screw cooler provided on the surface of the rotor is used as the axial flow compression device, so that the structure of the axial flow compression device can be significantly simplified.

FIG. 4 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts. The difference from the actual example in the second example is that the screw seal 8 is a stationary body and is provided on the surface of the nozzle box 1 facing the rotor 7. Even with such a structure, it is possible to obtain a pump action that creates the flow shown by the arrow C in the leakage space S.Research by FiM, W, Milligan et al. 2) K! Light 6: It is set to p-. According to the second embodiment, since the threaded seal part is not a rotating body, the threaded seal can be made into a split structure, resulting in good manufacturability.

Furthermore, as a modification of the first and second embodiments, the direction of the cooling steam flow C in the leakage space S is shown in FIGS. 1 and 4. It is also possible to form the threaded seal 8'1 so that it faces to the right. In that case, the action of the bolt 1 of the screw seal 8 increases the pressure at the right end of the leakage space S, that is, near the passage 220, thereby preventing the leakage steam flow B from passing through the seal piece 14 and mixing into the leakage space S. According to the present invention, without using special external cooling piping or cooling fluid, it is possible to effectively control the W supplementary installation (the second expansion stage) of the pot ratio turbine by reducing the pressure. can be cooled to
Not only does it work, but it also eliminates the need to create special holes in the rotor disc, which is subject to high temperatures and high stress, eliminating the stress concentration caused by holes, creating a high-pressure turbine rotor with strong shaft stability. The effect of being able to obtain

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a steam turbine rotor cooling device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line I-M in FIG. 1, and FIG. w1 figure, 4th
The figure is a longitudinal sectional view showing a steam turbine rotor cooling device which is another embodiment of the present invention.

Claims (1)

[Claims] 1. A steam turbine rotor cooling system that cools the rotor by flowing the steam that has passed through the rotor blades to the downstream and upstream sides of the rotor supported by the rotor blades. It is equipped with an annular nozzle box that directs the main steam flow to the stator blade and the stator blade that supports the rotor blade and the stator blade, which are disposed upstream of the C1 moving blade.
Between the vanes and the upstream 1111 surface of the rotor, there are first and second vanes designed to minimize the total leakage of unexpanded steam that has passed through the vanes.
The sealing device F leaks out to form a complete sealing space, and is equipped with a device that communicates with the sealing space to extract unexpanded steam from the sealing space. A pressure gradient is created in the axial direction of the rotor by the rotation of the rotor between the button and the nozzle box inside the nozzle box, which is arranged with a checkerboard;
- An axial flow compression device is provided, which guides the -S of the steam expanded after passing through the moving blades to the artificial side of the axial flow compression device through the inside of the silent 1N stage and the inner m of the stator blades. Equipped with a passageway,
The seal table of 812 *1 is adapted to restrict the flow of unexpanded steam from the seal space to the fluid pressure radiator 4), A-air turbine rotor cooling 112, patent claim No. 1 2. A steam turbine rotor cooling device characterized in that the axial flow compressor is provided with a screw-shaped protrusion on the upstream side of the rotor. 3. A steam turbine rotor cooling device according to claim 1, characterized in that a threaded fIII is provided on the inner surface of a nozzle box facing the upstream side of the rotor as a C1 trickle compression device.