JPH04129803U - Steam turbine stationary blade root ring drain removal device - Google Patents

Abstract

(57) [Summary] [Purpose] To enable drain to be removed from a stator blade root ring without affecting the performance of a stator blade of a steam turbine and without overflowing from a drain groove. [Configuration] Groove width W between the roots of the stator blades 2 on the inner wall of the stator blade root ring 3 is small enough not to affect the stator blade profile.
A drain groove A with a diameter is cut, the groove is gradually deepened from the upstream side to the downstream side of the drain groove A, and the drain is discharged from the inner wall of the blade root ring 3 toward the outer wall at the most downstream tail part of the drain groove A. Hole B was drilled.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a device for removing condensate from wet steam that is applied to stationary blades of a steam turbine. do.

0002

[Conventional technology]

The steam that mainly flows into the low-pressure stage of a steam turbine is humid and expands. Condensate is generated as the flow progresses. If this drain is left unattended, turbine blade efficiency will decrease. It also erodes the inlet edge of the low-pressure stage rotor blade, reducing plant thermal efficiency and causing maintenance problems. This results in an increase in maintenance costs.

0003 This phenomenon of condensate generation occurs in pressure water type (PWR type) nuclear power plants that use saturated steam. It occurs not only in the low-pressure turbine but also in the high-pressure turbine. Therefore, Countermeasures against lentils are an extremely important issue.

0004 Conventionally, the drain removal device is a stator blade and an internal casing to which the stator blade is attached. There are various devices that have been devised around the web, and the one shown in Figures 4 and 5 is one of them. Ru.

[0005] Figure 4 is a plan view of the inner wall of the stator vane ring, and Figure 5 is a diagram of the drain groove cut into the stator vane ring. It is a cross-sectional view, in which there is a dome with a width W and a depth H between the stator blade roots on the inner wall of the blade root ring 3 of the stator blade 2. A groove A is cut and the flow flows from the ventral side C to the dorsal side D of the stationary blade 2 along the chip wall. The drain is guided into the drain groove A, and the inner wall of the blade root ring 2 is connected to the groove tail on the downstream side of the drain groove A. The drain is guided and discharged from the drain hole B drilled toward the outer wall. . In both figures, the white arrows indicate the direction of steam flow, and the black arrows indicate the flow of condensate. Show direction.

[0006]

[Problem that the idea aims to solve] The above-mentioned conventional drain removal method involves cutting a groove between the stator blade roots on the inner wall of the stator blade root ring. In the control unit, the stator blades with a relatively large profile, such as the final stator blade group of the low pressure stage, are In this case, even if the groove width is made sufficiently large and the groove depth is reduced accordingly, the performance will not be affected. This is due to the small ratio of the groove dimension to the profile of the stator vane. When applied to a blade with a relatively small profile, it is necessary to You need to keep it small.

[0007] On the other hand, drain flows from the upstream side to the downstream side of the drain groove; The amount of drain increases as the temperature increases. In this way, overflow of condensate that gradually increases in volume If the depth of the drain groove is made uniformly deep to prevent flow, the groove head on the upstream side of the drain groove This is a contradictory phenomenon in that it causes a drop in suction pressure in the parts and affects performance. Ru.

[0008] The present invention has been made to eliminate this drawback.

[0009]

[Means to solve the problem]

The steam turbine stator blade root ring drain removal device of the present invention is Create a groove width between the roots of the stator blades on the inner wall that is small enough not to affect the stator blade profile. The drain groove is cut and gradually deepened from the upstream side to the downstream side of the drain groove. Comb, drain from the inner wall of the blade root ring to the outer wall at the most downstream tail part of the drain groove. Drill a discharge hole.

0010

[Effect]

In this invention, the drain flowing along the chip wall from the ventral side to the dorsal side of the stationary blade is It enters the drain groove and flows from the upstream side to the downstream side of the drain groove.

[0011] The amount of drain increases as it goes downstream, but the amount of drain increases as it goes downstream. Because the drain groove is deep, the drain will not overflow and will be placed at the very bottom of the drain groove. It reaches the downstream tail section and is discharged from the drain hole drilled in the tail section.

0012 In addition, the width of the drain groove is small enough to have no effect on the stator blade profile. The groove head on the upstream side of the drain groove is cut to a shallow groove depth. This eliminates the drop in suction pressure that occurs at the groove head and does not affect the performance of the stator blade. stomach.

[0013]

【Example】

An embodiment of the present invention will be described based on FIGS. 1 to 3. As shown in Figure 3 , the blade root ring 3 of the stationary blade 2 is fitted and attached to the internal casing 1 of the steam turbine. It is being

[0014] As shown in FIG. 1, a groove width W is provided between the stator blades 2 of the blade root ring 3. The drain groove A is cut along the stationary blade 2, and the groove tail on the most downstream side of the drain groove A A drain discharge hole B is bored in the blade root ring 3 from the inner wall to the outer wall. The drain is taken out to the outside. The groove width W of the drain groove A is static. It is set so small that it does not affect the blade profile.

[0015] As shown in FIG. 2, the groove head on the upstream side of the drain groove A has a shallow groove depth H. The groove depth H' becomes deeper toward the downstream side of the drain groove A. It has been deleted. The most downstream groove tail of the drain groove A is provided with a drain as described above. A drain hole B is provided.

[0016] In Figures 1 to 3, white arrows indicate the flow direction of steam, and black arrows indicate the direction of steam flow. Indicates drain flow direction.

[0017] In this embodiment configured as described above, the stator blade 2 is moved from the ventral side to the back side along the chip wall. Drain flowing toward the side enters drain groove A, and flows from the upstream side of drain groove A to the downstream side. The drain flows toward the downstream end of drain groove A, and the drain discharge hole is drilled in the same part. It is discharged from hole B.

[0018] The amount of drain flowing through drain groove A increases as it goes downstream, but Groove A gets deeper toward the downstream side, so the drain will not overflow. It flows through the drain groove A and is discharged from the discharge hole B.

[0019] The groove width W of the drain groove A is such that it does not affect the profile of the stationary blade 2. , and the groove head on the upstream side of drain groove A is cut to have a shallow groove depth. Therefore, there is no drop in suction pressure that occurs at the groove head of drain groove A, and the performance of the stationary blade is improved. It has no effect on

[0020]

[Effect of the idea]

According to the present invention, the width of the drain groove is set to such an extent that it does not affect the stator blade profile. In addition, the groove head on the upstream side of the drain groove has been cut so that the groove depth is shallow. Therefore, there is no drop in suction pressure that occurs at the head of the drain groove. Therefore, It does not have any effect on the profile performance of the stator blade.

[0021] In addition, the drain groove gets deeper as it goes downstream, so the amount of water that accumulates from the upstream side It can sufficiently handle the drain, and the drain will not overflow. Drain can be removed smoothly.

[Brief explanation of drawings]

FIG. 1 is a plan view of the inner wall of a blade root ring according to an embodiment of the present invention.

FIG. 2 is a sectional view of the drain groove of the blade root ring of the same embodiment.

FIG. 3 is a sectional view of the blade root ring of the same embodiment.

FIG. 4 is a plan view of the inner wall of a blade root ring of a conventional steam turbine.

FIG. 5 is a sectional view of a drain groove of a blade root ring of the conventional steam turbine.

[Explanation of symbols]

2 static wings 3 Stator blade root ring A Drain groove B Drain discharge hole W Drain groove width H, H′ Drain groove depth

Claims (1)

[Scope of utility model registration request] Claim 1: A drain groove having a groove width as small as not to affect the stator blade profile is cut between the stator blade roots on the inner wall of the stator blade root ring, and the drain groove is formed from the upstream side to the downstream side of the drain groove. A drain removal device for a steam turbine stator blade root ring, characterized in that the drain groove is gradually deepened, and a drain discharge hole is bored in the most downstream tail portion of the drain groove from the inner wall to the outer wall of the blade root ring.