阅读说明：本技术 一种核主泵连接管道非均匀来流抑制结构 (Non-uniform incoming flow restraining structure of nuclear main pump connecting pipeline ) 是由 龙云 强壮 朱荣生 于 2021-01-12 设计创作，主要内容包括：本发明提供了一种核主泵连接管道非均匀来流抑制结构,在连接管内设有导流板组件,导流板组件包括长板、短板、第一扭板和第二扭板；长板和短板均为长方形平板,设过管道轴线的一个轴向切面为基准面,所述长板和短板均位于此基准面上,且两者相对设置,分别固定在连接管相对的两侧内壁上；第一扭板和第二扭板分别固定在基准面两侧的管道内壁上,并相对基准面呈镜像对称；第一扭板和第二扭板的外形都为由长方形平板扭转变形而成,且扭转方向为：沿水流方向由长板侧向短板侧扭转。本发明抑制结构,能够在保证连接管总体输水速度不变的情况下,抑制管道内的非均匀来流,保障核主泵的平稳运行。(The invention provides a non-uniform inflow inhibition structure of a nuclear main pump connecting pipeline, wherein a guide plate assembly is arranged in a connecting pipe, and comprises a long plate, a short plate, a first torsion plate and a second torsion plate; the long plate and the short plate are rectangular flat plates, one axial tangent plane passing through the axis of the pipeline is a reference plane, and the long plate and the short plate are both positioned on the reference plane and are oppositely arranged and are respectively fixed on the inner walls of two opposite sides of the connecting pipe; the first torsion plate and the second torsion plate are respectively fixed on the inner walls of the pipelines at two sides of the datum plane and are in mirror symmetry relative to the datum plane; the first torsion plate and the second torsion plate are formed by twisting and deforming rectangular flat plates, and the twisting direction is as follows: the water flow direction is twisted from the long plate side to the short plate side. The inhibition structure can inhibit non-uniform incoming flow in the pipeline and ensure the stable operation of the nuclear main pump under the condition of ensuring that the overall water delivery speed of the connecting pipe is not changed.)

1. The utility model provides a non-uniform incoming flow of nuclear main pump connecting tube restraines structure which characterized in that: a guide plate assembly (3) is arranged in the connecting pipe (2), and the guide plate assembly (3) comprises a long plate (31), a short plate (32), a first torsion plate (33) and a second torsion plate (34); the long plate (31) and the short plate (32) are both rectangular flat plates, one axial tangent plane passing through the pipeline axis (21) of the connecting pipe (2) is a reference plane (22), the long plate (31) and the short plate (32) are both positioned on the reference plane (22), and the long plate and the short plate are oppositely arranged and respectively fixed on the inner walls of two opposite sides of the connecting pipe (2); the first torsion plate (33) and the second torsion plate (34) are respectively fixed on the inner wall of the connecting pipe (2) at two sides of the datum plane (22) and are in mirror symmetry relative to the datum plane (22); the first torsion plate (33) and the second torsion plate (34) are formed by twisting and deforming rectangular flat plates, and the twisting directions are as follows: the water flow direction is twisted from the long plate (31) side to the short plate (32) side.

2. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 1, wherein: the end surfaces of the long plate (31), the short plate (32), the first torsion plate (33) and the second torsion plate (34) on the outlet side of the connecting pipe (2) are coplanar.

3. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 1, wherein: the torsion shafts of the first torsion plate (33) and the second torsion plate (34) are pipeline axes (21), the torsion angle between the front end and the rear end is beta, and the beta is more than or equal to 60 degrees and less than or equal to 115 degrees.

4. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 3, wherein: the torsion angle β is 90 °.

5. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 4, wherein: one end of the first torsion plate (33) on the outlet side of the pipeline forms an included angle alpha of 45 degrees with the reference surface (22).

6. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 1, wherein: the axial lengths of the long plate (31), the first torsion plate (33) and the second torsion plate (34) are all c₁And c is and c₁Less than or equal to 0.59L; the short plate (3)2) Has an axial length of c₂And c is and c₂Less than or equal to 0.45L, wherein L is the length of the pipeline.

7. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 6, wherein: the long plate (31), the short plate (32), the first torsion plate (33) and the second torsion plate (34) are equal in width, a central flow passage with the diameter D is formed by the long plate (31), the short plate (32), the first torsion plate (33) and the second torsion plate (34) in a surrounding mode, and D is 0.1304D, wherein D is the inner diameter of the pipeline.

8. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 7, wherein: the thickness of the long plate (31), the short plate (32), the first torsion plate (33) and the second torsion plate (34) is b, and b is 0.01394D.

9. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 1, wherein: the long plate (31) is positioned on one side of a high flow velocity area in the pipeline, and the short plate (32) is positioned on one side of a low flow velocity area in the pipeline.

10. The non-uniform inflow suppressing structure of the connection pipe of the main nuclear pump according to claim 1, wherein: the distance between the plate surfaces of the long plate (31) and the short plate (32) on the two sides and the reference surface (22) is half of the plate thickness of the long plate and the short plate.

Technical Field

The invention belongs to the field of fluid systems, and particularly relates to a non-uniform inflow suppression structure of a nuclear main pump connecting pipeline.

Background

A reactor coolant circulation pump, i.e., a nuclear main pump, is an important device in relation to safe operation of a nuclear power plant. In the current third-generation nuclear power technology in China, a coolant circulating system consists of a reactor and two loops, the layout is compact, each loop is provided with a steam generator and two vertical main pumps, and the main pumps are inversely arranged at the bottom of the steam generator, so that a U-shaped connecting pipe is omitted from a main pipeline, and the resistance of a pipeline system is reduced. However, the design results in a short connecting part from the nuclear main pump to the lower chamber of the steam generator, thereby causing the incoming flow of the inlet of the nuclear main pump to be non-uniform.

The non-uniform incoming flow channel section has non-uniform speed distribution and overlarge speed gradient, so that the impeller blades and the pump shaft of the main pump are stressed unevenly, the vibration abrasion is aggravated, and the working efficiency of the pump is reduced; therefore, the non-uniform inflow is restrained, and the method is very key for guaranteeing the performance of the nuclear main pump.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a non-uniform inflow inhibition structure of a connecting pipeline of a nuclear main pump, which is used for enabling the flow velocity distribution in the connecting pipeline to tend to be stable.

The present invention achieves the above technical objects by the following technical means.

A non-uniform incoming flow restraining structure of a nuclear main pump connecting pipeline comprises: a guide plate assembly is arranged in the connecting pipe, and comprises a long plate, a short plate, a first torsion plate and a second torsion plate; the long plate and the short plate are rectangular flat plates, one axial tangent plane passing through the axis of the pipeline of the connecting pipe is a reference plane, and the long plate and the short plate are both positioned on the reference plane and are oppositely arranged and respectively fixed on the inner walls of two opposite sides of the connecting pipe; the first torsion plate and the second torsion plate are respectively fixed on the inner walls of the connecting pipe pipelines at two sides of the datum plane and are in mirror symmetry relative to the datum plane; the first torsion plate and the second torsion plate are formed by twisting and deforming rectangular flat plates, and the twisting direction is as follows: the water flow direction is twisted from the long plate side to the short plate side.

Further, the end surfaces of the long plate, the short plate, the first torsion plate and the second torsion plate on the outlet side of the connecting pipe pipeline are coplanar.

Furthermore, the torsion shafts of the first torsion plate and the second torsion plate are pipeline axes, the torsion angle between the front end and the rear end is beta, and the beta is more than or equal to 60 degrees and less than or equal to 115 degrees.

Further, the torsion angle β is 90 °.

Further, the angle α between one end of the first torsion plate on the outlet side of the pipeline and the reference plane is 45 °.

Further, the axial lengths of the long plate, the first torsion plate and the second torsion plate are all c₁And c is and c₁Less than or equal to 0.59L; the axial length of the short plate is c₂And c is and c₂Less than or equal to 0.45L, wherein L is the length of the pipeline.

Further, the long plate, the short plate, the first torsion plate and the second torsion plate are equal in width, a central flow passage with a diameter D is formed by the long plate, the short plate, the first torsion plate and the second torsion plate in a surrounding mode, and D is 0.1304D, wherein D is the inner diameter of the pipeline.

Further, the long plate, the short plate, the first torsion plate and the second torsion plate are all b in thickness, and b is 0.01394D.

Furthermore, the long plate is positioned on one side of a high flow velocity area in the pipeline, and the short plate is positioned on one side of a low flow velocity area in the pipeline.

Further, the distance from the plate surface of each of the long plate and the short plate to the reference surface is half of the plate thickness.

The invention has the beneficial effects that:

(1) the non-uniform incoming flow inhibiting structure of the nuclear main pump connecting pipeline can effectively reduce the highest flow speed in the connecting pipe between the low cavity and the nuclear main pump, improve the lowest flow speed, reduce the flow speed difference in the pipeline, enable the overall flow speed distribution condition to tend to be stable, achieve the effect of inhibiting non-uniform incoming flow, and further ensure the stable operation of the nuclear main pump; the suppression structure provided by the invention can suppress the non-uniform condition of the water flow without obviously attenuating the overall flow speed.

(2) The restraining structure of the invention only consists of four guide plates, has simple structure, does not occupy extra external space, and can be directly modified on the basis of the size of the existing connecting pipe.

(3) The invention provides relevant optimal size parameters of the guide plate assembly, and verifies the performance effect brought by the size parameters through simulation tests.

Drawings

FIG. 1 is a schematic diagram of a nuclear reactor coolant circulation system;

FIG. 2 is an axial view of a lower chamber of a nuclear power plant and its connecting pipes;

FIG. 3 is a partial view of the lower chamber and its connecting tube;

FIG. 4 is a perspective view of the lower chamber with the restraining structure of the present invention and its associated piping;

FIG. 5 is a side view of the lower chamber with the restraining structure of the present invention and its associated piping;

FIG. 6 is a front view of the lower chamber with the restraining structure of the present invention and its associated conduit;

FIG. 7 is a perspective view of a non-uniform incoming flow suppression structure in accordance with the present invention;

FIG. 8 is a front view of a non-uniform incoming flow suppression structure according to the present invention;

FIG. 9 is a block diagram of the baffle assembly of the present invention;

FIG. 10 is a side view of the baffle assembly of the present invention;

FIG. 11 is a top view of the baffle assembly of the present invention;

FIG. 12 is a front view of the baffle assembly of the present invention;

FIG. 13 is a dimensional view of the long and short plates of the present invention;

fig. 14 is a structural view of a first torsion plate and a second torsion plate of the present invention;

FIG. 15 is a dimensional drawing of a first torsion bar of the present invention;

FIG. 16(a) is a water flow velocity distribution diagram of the outlet section of a conventional connecting pipe;

FIG. 16(b) is a water flow velocity profile of the outlet cross section of a connecting tube with a suppression structure according to the present invention;

FIG. 17 is a graph showing the change in flow velocity in the diameter direction in the outlet section of the connecting tube.

Reference numerals:

1-a lower chamber; 2-connecting pipe; 21-the pipe axis; 22-a reference plane;

3-a guide plate assembly; 31-long plate; 32-short plates; 33-a first torsion plate;

34-second torsion plate.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1-2, a lower chamber 1 of a steam generator of a nuclear power plant is communicated with a nuclear main pump located below the lower chamber by a connecting pipe 2, the connecting pipe 2 is offset to one side of the lower chamber 1, and coolant flows into the nuclear main pump from the lower chamber 1 through the connecting pipe 2; this connection results in a relatively slow water flow rate toward the side of the central axis of the lower chamber 1 (i.e., the upper left side in fig. 2) and a relatively fast water flow rate toward the outside of the lower chamber (i.e., the lower right side in fig. 2) in the connection pipe 2.

As shown in fig. 3-6, the non-uniform inflow suppression structure of the present invention has a baffle assembly 3 disposed in the connection pipe 2; in the illustrated connecting pipe 2, one end close to the lower chamber 1 is a pipe inlet, one end far away from the lower chamber 1 is a pipe outlet, a pipe low flow velocity region is arranged above the illustration, and a pipe high flow velocity region is arranged below the illustration.

As shown in fig. 7 and 8, the pipe axis 21 is a central axis of the connecting pipe 2, the reference plane 22 is an axial section passing through the pipe axis 21, and the pipe inside diameter of the connecting pipe 2 is D and the length thereof is L.

The baffle assembly 3 is composed of a long plate 31, a short plate 32, a first torsion plate 33 and a second torsion plate 34. The long plate 31 and the short plate 32 are both rectangular flat plates and are arranged on the reference surface 22, wherein the distances from the plate surfaces on the two sides of the long plate 31 to the reference surface 22 are equal and are both half of the thickness of the long plate 31, and the distances from the plate surfaces on the two sides of the short plate 32 to the reference surface are equal and are both half of the thickness of the short plate 32; the long plate 31 and the short plate 32 are oppositely arranged and respectively fixed on the inner walls of two opposite sides of the pipeline. The first torsion plate 33 and the second torsion plate 34 are formed by twisting and deforming rectangular flat plates; the first torsion plate 33 and the second torsion plate 34 are respectively fixed on the inner wall of the pipeline on both sides of the reference plane 22, and are in mirror symmetry with the reference plane 22 as a symmetry plane.

As shown in fig. 5 and fig. 9 to 11, the short plate 32 is located on the low flow velocity region side and the long plate 31 is located on the high flow velocity region side in the pipe; on the side of the outlet of the pipeline, the end surfaces of the long plate 31, the short plate 32, the first torsion plate 33 and the second torsion plate 34 are in the same plane; the long plate 31 and the first and second torsion plates 33 and 34 have the same axial length; the twisting directions of the first torsion plate 33 and the second torsion plate 34 are: the water flow direction is twisted from the long plate 31 side to the short plate 32 side.

As shown in fig. 12 and 13, the long plate 31 has a length c₁The length of the short plate 32 is c₂The long plate 31 and the short plate 32 have a width and a thickness.

As shown in fig. 12, 14 and 15, the first torsion plate 33 has an axial length c₁The width of the torsion plate is a, the thickness of the torsion plate is b, the first torsion plate 33 is in torsion deformation by taking the pipeline axis 21 as a torsion shaft, the torsion angle between the front end and the rear end is beta, beta is more than or equal to 60 degrees and less than or equal to 115 degrees, and the included angle between one end positioned on the outlet side of the pipeline and the reference surface 22 is alpha. Since the second torsion plate 34 and the first torsion plate 33 are mirror-symmetrical with respect to the reference plane 22, the second torsion plate 34 also has an axial length c₁The width of the torsion plate is a, the thickness of the torsion plate is b, the second torsion plate 34 is also in torsional deformation by taking the pipeline axis 21 as a torsional axis, the torsional angle between the front end and the rear end is beta, and the included angle between one end positioned on the outlet side of the pipeline and the reference plane 22 is alpha.

As shown in fig. 8 and 13, a central flow passage with a diameter D is formed by the long plate 31, the short plate 32, the first torsion plate 33 and the second torsion plate 34, and D-2a is provided.

For each of the above dimensions, the preferred parameters of the present embodiment are set as follows:

c₁≤0.59L，c₂≤0.45L，b＝0.01394D，d＝0.1304D，β＝90°，α＝45°。

simulating the condition that the cooling liquid flows into the nuclear main pump from the lower cavity 1 through the connecting pipe 2 by ANSYS CFX simulation software, wherein the water flow velocity distribution condition of the outlet section of the pipeline is shown in a figure 16(a) when a common connecting pipe is adopted, and the water flow velocity distribution condition of the outlet section of the pipeline is shown in a figure 16(b) when the connecting pipe with the inhibiting structure is adopted; the orientation of the view of fig. 16 corresponds to the orientation of the view of the connection tube shown in fig. 2, with the lighter color in fig. 16 corresponding to the lower and higher flow rates. As can be seen from fig. 16, when the common connecting pipe is used, the flow velocity gradient in the pipeline is obvious, and the high flow velocity region is relatively deviated to the lower right; when the restraining structure of the present invention is employed, the flow velocity distribution of the water flow tends to be uniform.

Taking 50 flow velocity measurement points along the diameter direction of the graph in fig. 16, drawing a radial flow velocity change curve chart at the outlet of the connecting pipe shown in fig. 17, wherein a curve shortshell is the flow velocity change of the common connecting pipe, and a curve Nbladecase is the flow velocity change of the connecting pipe with the restraining structure of the invention. As can be seen from fig. 17, compared with a common connecting pipe, the highest flow velocity at the outlet of the connecting pipe with the suppression structure of the present invention is reduced, the lowest flow velocity is increased, and the trend of the total flow velocity change curve is more gradual, thereby indicating that the non-uniform incoming flow suppression structure of the present invention effectively suppresses the non-uniform incoming flow in the pipe, so that the overall flow velocity tends to be stable; compared with the common connecting pipe, the restraining structure does not obviously attenuate the flow speed of the water flow of the whole pipeline.

In conclusion, the suppression structure can suppress non-uniform inflow in the pipeline and guarantee the stable operation of the nuclear main pump under the condition of ensuring that the overall water delivery speed of the connecting pipe is not changed.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. The present invention is not limited to the above-described embodiments, and any obvious improvement, replacement or modification by those skilled in the art can be made without departing from the spirit of the present invention.