CN115749972A - Hollow quiet leaf dehumidification structure of marine 10MW level steam turbine - Google Patents

Abstract

The invention relates to a hollow stationary blade dehumidification structure for a marine 10MW steam turbine, which is composed of a hollow stationary blade, an outer ring of a partition, an inner belt of a partition, and an inner ring of a partition; the pressure surface of the hollow static blade is provided with double rows of suction gaps , the double-row suction slots are located in the upper half of the blade height, close to the exit edge of the hollow stationary vane, and there are suction holes in the outer ring of the clapboard, the suction slots distributed along the blade height, the internal cavity of the hollow stationary vane and the suction holes After leading to the stage, a pressure difference is formed, which can suck the water film attached to the surface of the hollow static blade to the cavity of the hollow static blade, preventing the water film on the surface of the hollow static blade from breaking and forming large water droplets into the moving blade to form water erosion. The invention is applied to the dehumidification of the last-stage stationary blades of a 10MW steam turbine, and improves the reliability of the safe operation of the steam turbine.

Description

A hollow vane dehumidification structure for a marine 10MW steam turbine

technical field

The invention relates to a hollow stationary vane of a marine steam turbine, in particular to a hollow stationary vane dehumidification structure for a 10MW marine steam turbine.

Background technique

As the prime mover, the steam turbine converts the thermal energy of the high-temperature and high-pressure steam into the mechanical energy of the high-speed rotation of the steam turbine rotor. When the steam flows through the last few stages of blades, the dryness of the steam decreases and the humidity increases. Large and small liquid droplets will appear in the steam, which will affect the The last few stages of blades produce impacts, causing water erosion of the blades, which reduces the efficiency of the steam turbine, increases the vibration of the steam turbine, and causes damage such as fatigue cracks on the blades.

Common measures for steam turbine through-flow dehumidification and anti-corrosion design include ① set up dehumidification grooves between stages and drain water step by step, ② appropriately increase the gap between stages, ③ house-shaped moving blade dehumidification structure, ④ optimize the design of moving and stationary blades, ⑤ low-pressure blades Surface treatment etc.

The hollow vane structure is a measure for the dehumidification of the steam turbine through flow, and the dehumidification effect is more obvious when it is installed on the final stage diaphragm of the steam turbine. Set up a dehumidification slit at the appropriate position on the pressure surface and suction surface of a single stator blade, and use the gap to lead to the stage to form a pressure difference to suck the flowing water film or stream on the surface of the stator blade, reducing the water film or stream at the outlet of the stator blade. The number of large water droplets formed by tearing can achieve the purpose of dehumidification; or pass high-temperature steam to the hollow stationary vane to heat the wall of the stationary vane so that the water film attached to the surface of the vane is heated and evaporated; or the trailing edge of the hollow stationary vane is slit to The jet of hot steam breaks up the large water droplets that fall off the trailing edge.

The existing hollow vane structure of marine 10MW steam turbine mainly has the following problems:

(1) There is no relevant hollow vane dehumidification structure design for marine steam turbines.

(2) The hollow vane structure is mainly used in high-humidity and high-power units. Small steam turbines are limited in space and structural design is difficult, and there is no relevant use record.

(3) A large number of literatures focus on the analysis of the dehumidification performance of the hollow vane, lacking the design and practical application cases of the overall hydrophobic dehumidification structure.

Contents of the invention

The problem to be solved by the present invention is to provide a hollow vane dehumidification structure for a marine 10MW steam turbine, which is used to solve the following technical problems:

1. The hollow vane dehumidification structure is also applicable to the final vane of the 10MW steam turbine: because the final vane of the small steam turbine is small, the design of the hollow vane is difficult, and the erosion index of the 10MW steam turbine is still relatively large, so it is necessary to use the hollow vane The static leaf dehumidification structure, the design of the present invention can meet the requirements of use.

2. The design of the dehumidification structure of the hollow stationary blade is reasonable. Under the condition of meeting the strength and process requirements, the relative position of the gap, the width and angle of the gap, and the treatment of the edge of the gap are designed to optimize the structure. The influence of the steam flow field in the channel is small.

3. The dehumidification effect is remarkable. It can remove most of the water that is harmful to the moving blades. It not only slows down or eliminates the water erosion of the moving blades, but also reduces the friction and braking losses caused by large water droplets, and improves the safety and reliability of the steam turbine operation. Improve the thermal efficiency of the entire power plant.

The technical solution of the present invention is: a hollow vane dehumidification structure for a marine 10MW steam turbine, which is composed of a hollow stationary vane, an outer ring of a partition, an inner belt of a partition, and an inner ring of a partition; Rows of suction slits, the double row of suction slits are located in the upper half of the blade height, close to the exit edge of the hollow stationary vane, there are suction holes in the outer ring of the partition, the suction slits distributed along the blade height, the internal cavity of the hollow stationary vane and The suction hole leads to the back of the stage as a whole to form a pressure difference, which can suck the water film attached to the surface of the hollow static blade to the cavity of the hollow static blade, preventing the water film on the surface of the hollow static blade from breaking and forming large water droplets into the moving blade to form water erosion .

Further, the hollow stationary vane is made by precision casting, and along the blade height direction, the interior of the entire vane is a cavity.

Further, the hollow stationary vanes are welded to the inner shroud of the partition to ensure that the positions of the vanes are consistent with the suction holes.

Further, the inner peripheral band of the partition is welded on the inner ring of the partition, the top of the hollow stationary vane is located in the outer ring of the partition, and a suction hole is provided in the outer ring of the partition, and the inner cavity of the hollow stationary vane leads to the after grade.

Furthermore, most of the water droplets carried by the high-speed steam in the cavity of the hollow stationary blade are directly pumped to the stage, and the water droplets that have not been pumped are collected into the inner ring cavity of the inner wall of the partition under the action of gravity. , flows to the lower half of the outer ring of the clapboard, and under the action of pressure difference, the water droplets are guided from the cavity to the rear of the stage, thereby dehumidifying.

The beneficial effects of the present invention are:

The present invention adopts above technical scheme, has the following advantages:

(1) A small steam turbine hollow vane structure is obtained. Although the final vane of the small steam turbine is small, the space is cramped, and the structural design and manufacturing are difficult, it has been proved that the small steam turbine is still suitable for the hollow vane structure.

(2) The theoretical dehumidification effect is remarkable. Through continuous optimization of the structure, the most suitable relative position of the gap, gap width and angle, and the structural size of the gap edge treatment are obtained.

(3) Finished the processing and manufacturing, and applied it to the dehumidification of the last-stage stationary vanes of 10MW steam turbines to improve the reliability of the safe operation of the steam turbines.

Description of drawings

Fig. 1 is a half-sectional view of the dehumidification structure of the hollow vane of the present invention;

Fig. 2 is the overall appearance of the hollow vane dehumidification structure of the present invention

Fig. 3 is a schematic diagram of the structure of a single hollow stator blade;

Fig. 4 is an installation diagram of the dehumidification structure of the hollow vane.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figures 1 and 2, the hollow vane dehumidification structure of the present invention consists of a hollow vane 1, an outer ring 5 of a partition, an inner band 3 of the partition, and an inner ring 4 of the partition.

The hollow stator blade 1 is shown in Figure 3. The hollow stator blade 1 adopts precision casting technology. Along the blade height direction, the inside of the blade is a cavity. Double rows of suction gaps 2 are set on the pressure surface of the blade. The position is in the upper half of the blade height. As close as possible to the outlet edge of the hollow blade, the blade structure is designed reasonably, and the dehumidification efficiency reaches the theoretical highest.

The hollow static vane 1 is welded on the inner shroud 3 of the clapboard and the position of the vane is consistent with that of the suction hole 6, and the dehumidification effect can only be exerted by cooperating with the overall structural design.

The inner peripheral belt 3 of the partition is welded on the inner ring 4 of the partition, the top of the hollow stationary vane 1 is located in the outer ring 6 of the partition, the outer ring 5 of the partition is provided with a suction hole 6, the internal cavity of the hollow stationary vane 1 and the suction Hole 1 leads to post-stage 8.

The working principle is: the dehumidification gap distributed along the blade height, the internal cavity of the blade and the suction hole lead to the rear stage 8 as a whole, forming a pressure difference, which can suck the water film attached to the surface of the hollow static blade 1 into the cavity, preventing The water film on the surface of the stationary leaves breaks and large water droplets enter the moving leaves to form water erosion. The steam velocity in the cavity of the hollow static vane 1 is relatively high, and the ability to carry water droplets is strong, and it can directly pump away most of the water droplets to the stage, and the water droplets that have not been taken away will gather to the inner ring of the inner wall of the partition 3 under the action of gravity The cavity 7 flows to the lower half of the inner ring 4 of the partition, and under the action of the pressure difference, water droplets are guided from the cavity to the rear of the stage, thereby dehumidifying.

In the flow structure of the steam turbine, a stage is composed of a set of hollow stationary blades 1 and a set of rotor moving blades 9, which is the unit for steam expansion to do work. The entire flow structure can be divided into many stages. The separator vane is installed at the last stage of the steam turbine, as shown in Figure 4.

Claims (5)

1. The utility model provides a hollow quiet leaf dehumidification structure of marine 10MW level steam turbine which characterized in that: the diaphragm is composed of hollow stationary blades, a diaphragm outer ring, a diaphragm inner surrounding belt and a diaphragm inner ring; the double-row suction gap is formed in the pressure surface of the hollow stationary blade, the double-row suction gap is located at the upper half of the blade height and is close to the outlet edge of the hollow stationary blade, a suction hole is formed in the outer ring of the partition, and the suction gap, the hollow stationary blade inner cavity and the suction hole which are distributed along the blade height are integrally led to the stage to form pressure difference, so that a water film attached to the surface of the hollow stationary blade can be sucked into the cavity of the hollow stationary blade, and the water film on the surface of the hollow stationary blade is prevented from being broken to form large water drops to enter the movable blade to form water erosion.

2. The hollow stationary blade dehumidification structure of a marine 10MW stage steam turbine according to claim 1, wherein: the hollow stationary blade is manufactured by precision casting, and a cavity is formed inside the whole blade along the blade height direction.

3. The hollow stationary blade dehumidification structure of a marine 10MW stage steam turbine according to claim 1, wherein: the hollow stationary blades are welded on the inner surrounding belt of the clapboard and ensure that the blades are consistent with the suction holes.

4. The hollow stationary blade dehumidification structure of a marine 10MW stage steam turbine according to claim 1, wherein: the diaphragm inner surrounding band is welded on the diaphragm inner ring, the top of the hollow static blade is positioned in the diaphragm outer ring, a suction hole is formed in the diaphragm outer ring, and a cavity in the hollow static blade is led to the stage back through the suction hole.

5. The hollow stationary blade dehumidification structure of a marine 10MW stage steam turbine according to claim 1, wherein: most of water drops carried by high-speed steam in the cavity of the hollow stationary blade are directly pumped to the stage, the water drops which are not pumped are collected to the inner ring cavity of the inner shroud of the partition plate under the action of gravity and flow to the lower half of the outer ring of the partition plate, and the water drops are guided to the stage from the cavity under the action of pressure difference, so that the dehumidification effect is achieved.

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