Grading rectifying device applied to steam exhaust channel

Abstract

The utility model discloses a grading rectifying device applied to a steam exhaust channel, which comprises a steam turbine low-pressure cylinder, a condenser throat part, a steam extraction pipeline, a low-pressure heater, a small steam turbine steam exhaust port, a first-stage rectifying device, a second-stage rectifying device and a third-stage rectifying device, a steam extraction pipeline and a low-pressure heater are arranged in the condenser throat part, a steam exhaust port of the small steam turbine is arranged on one inclined wall face of the condenser throat part, the first-stage rectifying device is arranged on the inner wall of a low-pressure cylinder of the steam turbine, the second-stage rectifying devices are arranged on the two sides of the steam extraction pipeline, and the third-stage rectifying device is arranged below the steam exhaust port of the small steam turbine. The utility model has the beneficial effects that the steam flow at the outlet of the steam exhaust channel is more uniformly distributed, so that the speed distribution of steam at the inlet of the tube bundle area of the condenser is improved, and the heat exchange performance of the condenser is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine condensers, and specifically, to a hierarchical rectifying device applied to an exhaust passage. Background Art

[0002] As the steam flow passage connecting the last stage of the steam turbine and the condenser, the exhaust passage is mainly composed of the low-pressure cylinder of the steam turbine and the throat of the condenser, and guides the exhaust steam from the last stage of the steam turbine into the condenser. In order to save the space occupied by the equipment, the low-pressure exhaust cylinder of the steam turbine usually adopts an axial annular steam inlet and downward steam exhaust layout. The exhaust steam from the last stage of the steam turbine will experience a 90° flip from axial to radial in the low-pressure exhaust cylinder. The huge pressure gradient will cause the air flow to form large-scale vortices. And due to the existence of equipment and pipelines such as low-pressure heaters, the exhaust port of the small steam turbine, extraction pipes and support frames, the internal structure of the exhaust passage is more complex, and the steam flow field is very disordered. This directly causes adverse effects such as an increase in the steam flow resistance in the exhaust passage and an increase in the non-uniformity of the flow field. The stability of the steam flow in the exhaust passage and the uniformity of the distribution not only affect the vacuum of the condenser, but also affect the safety of the cooling tube bundles in the condenser. Therefore, it is necessary to optimize and transform the exhaust passage to make the flow field at the outlet of the exhaust passage more reasonable, so as to improve the vacuum of the condenser and reduce the exhaust steam pressure of the steam turbine. Content of the Utility Model

[0003] In order to overcome the deficiencies of the above-mentioned prior art, the utility model provides a hierarchical rectifying device applied to an exhaust passage, which can reduce the eddy current in the exhaust passage, make the flow field at the outlet of the exhaust passage more reasonable, improve the heat exchange performance of the condenser, and further improve the vacuum of the condenser and reduce the exhaust steam pressure of the steam turbine.

[0004] To achieve the above technical purpose, the utility model adopts the following technical solutions:

[0005] A hierarchical rectifying device applied to an exhaust passage includes a low-pressure cylinder of a steam turbine, a throat of a condenser, an extraction pipeline, a low-pressure heater, an exhaust port of a small steam turbine, a primary rectifying device, a secondary rectifying device, and a tertiary rectifying device. The lower side of the low-pressure cylinder of the steam turbine is connected to the throat of the condenser. The extraction pipeline and the low-pressure heater are arranged in the throat of the condenser. The exhaust port of the small steam turbine is arranged on an inclined wall surface of the throat of the condenser. The primary rectifying device is arranged on the inner wall of the outer cylinder of the low-pressure cylinder of the steam turbine. The secondary rectifying device is arranged on both sides of the extraction pipeline and near the low-pressure heater. The tertiary rectifying device is arranged below the exhaust port of the small steam turbine.

[0006] Further, the outer shape of the primary rectifying device is a rectifying structure composed of a ring and a straight line segment, with a depth of 0.3 - 0.4 m, symmetric about the vertical middle plane of the low-pressure cylinder of the steam turbine, and arranged on the inner wall of the outer cylinder of the low-pressure cylinder of the steam turbine.

[0007] Furthermore, the shape of the secondary rectifying device can be an arc plate or a flat plate, which are respectively arranged on both sides of the extraction steam pipeline and near the low-pressure heater. The arc angle is 20°-30°, and the arc length is 0.7m-1.0m.

[0008] Furthermore, the tertiary rectifying device can be an arc plate or a flat plate, with a length of 1.2m-1.5m, and the width is the same as the diameter of the exhaust port of the small steam turbine. It is arranged below the exhaust port of the small steam turbine.

[0009] The beneficial effects of the present utility model: By arranging a hierarchical rectifying device in the exhaust passage, after the exhaust steam flow of the low-pressure cylinder of the steam turbine and the exhaust steam of the small steam turbine are respectively rectified by the rectifying device, the eddy current in the exhaust passage is reduced, the flow field at the outlet of the exhaust passage becomes more reasonable, the heat transfer performance of the condenser is improved, and thus the vacuum of the condenser is increased and the exhaust steam pressure of the steam turbine is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required in the embodiments.

[0011] Figure 1 is a schematic structural diagram of an embodiment of the present utility model.

[0012] Figure 2 is Figure 1 the front view of

[0013] Figure 3 is Figure 1 the side view of

[0014] Explanation of the marks in the figure:

[0015] 1 - Low-pressure cylinder of the steam turbine, 2 - Throat of the condenser, 3 - Extraction steam pipeline, 4 - Low-pressure heater, 5 - Exhaust port of the small steam turbine, 6 - Primary rectifying device, 7 - Secondary rectifying device, 8 - Tertiary rectifying device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will describe the present utility model in detail with reference to the drawings and specific embodiments.

[0017] A hierarchical rectifying device applied to an exhaust passage, as Figure 1As shown in the figure, a hierarchical rectification device applied to an exhaust passage includes a low-pressure cylinder 1 of a steam turbine, a condenser throat 2, an extraction steam pipeline 3, a low-pressure heater 4, an exhaust port 5 of a small steam turbine, a primary rectification device 6, a secondary rectification device 7, and a tertiary rectification device 8. The lower side of the low-pressure cylinder 1 of the steam turbine is connected to the condenser throat 2. The extraction steam pipeline 3 and the low-pressure heater 4 are arranged in the condenser throat 2. The exhaust port 5 of the small steam turbine is arranged on an inclined wall surface of the condenser throat 2. The primary rectification device 6 is arranged on the inner wall of the outer cylinder of the low-pressure cylinder 1 of the steam turbine. The secondary rectification device 7 is arranged on both sides of the extraction steam pipeline 3. The tertiary rectification device 8 is arranged below the exhaust port 5 of the small steam turbine.

[0018] The outer shape of the primary rectification device 6 is a rectification structure composed of a ring and a straight section, with a depth of 0.3 - 0.4 m, symmetric about the vertical middle plane of the low-pressure cylinder 1 of the steam turbine, and arranged on the inner wall of the outer cylinder of the low-pressure cylinder 1 of the steam turbine.

[0019] The outer shape of the secondary rectification device 7 can be an arc plate or a flat plate, with a width of 6.4 m - 7.2 m, an arc angle of 20° - 30°, and an arc length of 0.7 m - 1.0 m, and is respectively arranged on both sides of the extraction steam pipeline 3 and near the low-pressure heater 4.

[0020] The tertiary rectification device 8 can be an arc plate or a flat plate, with a length of 1.2 m - 1.5 m, and a width the same as the diameter of the exhaust port 5 of the small steam turbine, and is arranged below the exhaust port 5 of the small steam turbine.

[0021] The effect of setting the primary rectification device 6 is to pass through the vortex area inside the low-pressure cylinder 1 of the steam turbine, effectively destroy the vortex structure, and at the same time avoid the influence of the spiral steam flow on the steam flow at the outlet of the exhaust guide ring, improving the internal flow field of the low-pressure cylinder 1 of the steam turbine; the effect of setting the secondary rectification device 7 is to rectify the steam from the low-pressure cylinder of the steam turbine, weaken the influence of the extraction steam pipeline 3 and the low-pressure heater 4 on the flow field, and make the flow field passing through the condenser throat 2 more stable and uniform; the effect of setting the tertiary rectification device 8 is to guide a part of the exhaust steam of the feed water small steam turbine to flow below the exhaust port 5 of the small steam turbine, reduce the area of the low-speed vortex area formed below the exhaust port 5 of the small steam turbine, and weaken the impact of the exhaust steam of the small steam turbine on the exhaust steam of the steam turbine. By arranging a hierarchical rectification device in the exhaust passage, the vortex intensity in the internal flow field of the exhaust passage is weakened, and the uniformity of the channel flow field is improved.

[0022] In summary, by means of the above technical solutions of the present invention, a hierarchical rectification device is arranged in the exhaust passage. After the exhaust steam flow of the low-pressure cylinder of the steam turbine and the exhaust steam of the small steam turbine are respectively rectified by the rectification device, the vortex intensity in the low-pressure cylinder of the steam turbine is weakened, the steam flow distribution at the outlet of the exhaust passage becomes more uniform, thereby improving the velocity distribution of the steam at the inlet of the condenser tube bundle area, enhancing the heat transfer performance of the condenser, and further increasing the condenser vacuum and reducing the exhaust steam pressure of the steam turbine.

[0023] The above embodiments are not intended to limit the present utility model, and any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present utility model also fall within the protection scope of the present utility model.

Claims

1. A graded rectifier device applied to an exhaust passage, comprising a low-pressure cylinder (1) of a steam turbine, a throat (2) of a condenser, a steam extraction pipeline (3), a low-pressure heater (4), a small steam turbine exhaust port (5), a primary rectifier (6), a secondary rectifier (7), and a tertiary rectifier (8), wherein the lower side of the low-pressure cylinder (1) of the steam turbine is connected to the throat (2) of the condenser, a steam extraction pipeline (3) and a low-pressure heater (4) are arranged in the throat (2) of the condenser, and the small steam turbine exhaust port (5) is arranged on an inclined wall surface of the throat (2) of the condenser, characterized in that: The first-stage rectifying device (6) is arranged on the inner wall of the outer cylinder of the low-pressure cylinder (1) of the steam turbine, the second-stage rectifying device (7) is arranged on both sides of the steam extraction pipeline (3), and the third-stage rectifying device (8) is arranged below the steam exhaust port (5) of the small steam turbine.

2. According to claim 1, a graded rectifying device applied to an exhaust passage is characterized in that: The first-stage rectifying device (6) has an outer shape of a rectifying structure composed of a ring and a straight line segment, has a depth of 0.3-0.4 m, is symmetrical about the vertical center plane of the steam turbine low-pressure cylinder (1), and is arranged on the inner wall of the outer cylinder of the steam turbine low-pressure cylinder (1).

3. According to claim 1, a graded rectifying device applied to an exhaust passage is characterized in that: The secondary rectifier (7) can be in the shape of an arc plate or a straight plate, with a width of 6.4m-7.2m, an arc angle of 20°-30°, and an arc length of 0.7m-1.0m, and is respectively arranged on both sides of the steam extraction pipeline (3) and near the low-pressure heater (4).

4. A graded rectifying device applied to an exhaust passage according to claim 1, characterized in that: The three-stage rectifying device (8) can be a curved plate or a straight plate, with a length of 1.2m-1.5m and a width the same as the diameter of the small steam turbine exhaust port (5), and is arranged below the small steam turbine exhaust port (5).

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