Test apparatus and sealing method for nuclear reactor flow field testing

Abstract

This invention discloses a test apparatus and sealing method for nuclear reactor flow field testing. The test apparatus includes a cylindrical body and a transparent window. The cylindrical body has an annular fluid cavity, and a window with an unsealed bottom is opened in the lower part of the side wall of the cylindrical body. The transparent window includes a transparent body sealed inside the window and a branch pipe inlet pipe disposed on the transparent body. The transparent body has a U-shaped longitudinal section, forming a visualization cavity inside. The branch pipe inlet pipe is connected to the visualization cavity. The fluid cavity and the visualization cavity are interconnected without affecting the original flow characteristics of the fluid. This invention achieves sealing by embedding the transparent window into the cylindrical body and pressing it tightly. On the one hand, it ensures that the flow channel inside the cylindrical body is not changed by the addition of the transparent window. On the other hand, it can monitor the flow inside the cylindrical body from multiple directions, providing conditions for measuring the flow field inside the cylindrical body, especially on the wall or near the intersection line of the transparent window and the branch pipe.

Description

Technical Field

[0001] This invention relates to the field of nuclear power experimental equipment technology, and in particular to a test apparatus and sealing method for nuclear reactor flow field testing. Background Technology

[0002] In industrial production or experimental research, it is sometimes necessary to install viewing windows on equipment to observe the flow of fluids within it. Existing technologies commonly use planar viewing windows, which are sealed by clamping rings pressed against a mounting base. However, this design suffers from limitations such as a single shape, the window being confined to a single plane, limiting the viewing direction, and the need for a mounting base that alters the internal flow path of the container in the mounting area. These limitations make the design unsuitable for non-planar structures like cylinders or annular cavities where a continuous curved surface is required.

[0003] In nuclear reactor flow field experiments, precise measurement techniques such as particle imaging velocimetry (PIV) and laser-induced fluorescence (LIF) are required to obtain the velocity, temperature, and concentration fields of specific areas of important equipment such as the reactor core pressure vessel and steam generator. Therefore, viewing windows need to be set on the experimental components. These viewing windows must ensure that the original flow channels are not changed by the addition of the viewing windows, and also allow monitoring of the flow within a specific structure from multiple directions, especially the flow in areas near the walls or intersections that are subject to pressure thermal shock or severe hot and cold alternation.

[0004] Chinese patent document application number 201510590914.2 discloses a detachable cryogenic fluid visualization window that uses a planar transparent plate as the visualization window. The structure achieves a seal at low temperatures by utilizing the difference in thermal expansion coefficients between the inner tube, outer tube, and transparent plate. This window structure requires extending a branch from the original cylindrical surface of the tank to accommodate the window, altering the shape of the fluid domain. Furthermore, the visualization direction is singular; it can observe boiling or liquid level, but it cannot measure the flow field using particle image velocimetry or laser-induced fluorescence techniques.

[0005] Chinese patent document application number 201510136432.X discloses a self-sealing cryogenic fluid visualization device. It uses a transparent tube to achieve visualization, and the structure achieves self-sealing at low temperatures by utilizing the difference in thermal expansion coefficients of the transparent tube and the two connecting sections before and after it. The viewing window is tubular, suitable for small-sized tubes, but not suitable for viewing windows on thick, large pipes or tanks. Due to the difference in diameter among the three tube sections, there is a significant narrowing and widening of the flow channel, which interferes with the flow field to be observed.

[0006] The aforementioned visualization structures are all regular shapes, with their windows either circular lenses or uniform cylindrical tubes. They cannot effectively simulate flow in structures with poor regularity, have limited visibility directions, and relatively small window structures. They are only suitable for qualitative observation of internal flow by the naked eye or a camera, and cannot be used to measure multiple parameters such as velocity distribution, temperature distribution, and concentration distribution in the internal flow field using precise measurement methods such as particle imaging velocimetry (PIV) and laser-induced fluorescence (LIF) in complex structures.

[0007] The article "Development and Flow Field Visualization of High-Speed ​​Water Discharge Device" (Vol. 28, No. 4, July 2011) in the Journal of Zhejiang Sci-Tech University describes a visual flow field experimental device. The water tank for visualization is a square stainless steel body, with observation windows set on the planes around the tank. The article "Visualization Experiment of Local Thermal Flow Field of Supercritical CO2 in a Rectangular Channel" (Vol. 75, No. 8, 2024) in the Journal of Chemical Industry also uses a planar viewing window opened on a square stainless steel channel body.

[0008] Chinese patent document application number 201320484925.9 discloses a hydraulic experimental headbox capable of flow field measurement and visualization. Its structure is mainly composed of regular cuboids or prisms, and except for fasteners, it is made of plexiglass. All connections requiring fasteners are planar seals, employing tongue-and-groove structures and convex-concave surface mating structures to ensure the flow channel dimensions. Existing visualization devices can be summarized as either a steel planar structure with a small planar window, or a fully transparent structure. These two methods are applicable to simple structures, and the flow field visualization area is mainly within various cavities. Furthermore, convex-concave seals and tongue-and-groove seals are limited to planar structure sealing. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a test device and sealing method for nuclear reactor flow field testing.

[0010] The technical solution adopted by this invention to solve its technical problem is:

[0011] A test apparatus for nuclear reactor flow field testing, comprising:

[0012] The cylinder has an annular fluid cavity and an open window on the lower part of the side wall.

[0013] A transparent viewing window includes a transparent body sealed within the window and a branch inlet pipe disposed on the transparent body. The transparent body has a U-shaped longitudinal section and forms a visualization cavity inside. The branch inlet pipe is connected to the visualization cavity. The fluid annular cavity is connected to the visualization cavity without affecting the original flow characteristics of the fluid. This allows for fluid observation of the visualization cavity and the branch inlet pipe region from multiple directions, including from the outside of the transparent body to the inside, from the inside to the outside, and from the bottom to the top.

[0014] Furthermore, in the aforementioned test apparatus for nuclear reactor flow field testing, preferably, the test apparatus further includes a sealing assembly detachably mounted on the cylinder for sealing the transparent body to the window. The sealing assembly includes a pressure strip covering the front and rear edges of the window and extending to the wall of the cylinder to fix the circumferential edge of the transparent body; or / and the sealing assembly further includes two support plates covering the two sides of the window opening to support the bottom of the transparent body upwards and extending to the bottom of the cylinder.

[0015] Furthermore, in the test apparatus for a nuclear reactor flow field test, preferably, a main flow inlet assembly connected to the fluid annular cavity is also installed on the cylinder to allow fluid to enter the fluid annular cavity; the main flow inlet assembly includes a connecting pipe section, a rectifier pipe section and a connecting pipe section connected in sequence, the connecting pipe section is disposed on the cylinder, and the rectifier pipe section is provided with a rectifier grid for smooth fluid flow.

[0016] Alternatively, a branch pipe may also be connected to the inlet pipe of the branch pipe.

[0017] Furthermore, in the test apparatus for a nuclear reactor flow field test, preferably the radius of curvature of the fluid annular cavity wall is the same as the radius of curvature of the visualization cavity wall, and the radius of curvature of the bottom of the fluid annular cavity is the same as the radius of curvature of the bottom of the visualization cavity, and they are on the same horizontal plane, so that the fluid annular cavity wall and the visualization cavity wall can transition smoothly.

[0018] Furthermore, in the test apparatus for a nuclear reactor flow field test, preferably the lateral width of the transparent body increases sequentially from top to bottom, or / and the top corners on both sides of the transparent body are rounded, and the shape of the window matches the shape of the transparent body.

[0019] Furthermore, in the test apparatus for a nuclear reactor flow field test, the cylindrical body preferably includes an outer cylinder, an inner cylinder, and an annular bottom plate. The inner cylinder is disposed inside the outer cylinder, and the annular bottom plate is installed at the bottom of the outer cylinder and the inner cylinder. The outer cylinder, the inner cylinder, and the annular bottom plate together define the fluid annular cavity.

[0020] Or / and the transparent body includes a transparent outer plate, a transparent inner plate, and a transparent bottom plate, wherein the transparent bottom plate is installed at the bottom of the transparent outer plate and the transparent inner plate, and the transparent outer plate, the transparent inner plate, and the transparent bottom plate together define the visualization cavity.

[0021] Furthermore, in the experimental apparatus for a nuclear reactor flow field test, preferably, the outer cylinder has a first mounting groove, the inner cylinder has a second mounting groove, and the annular bottom plate has a third mounting groove, the first mounting groove, the second mounting groove, and the third mounting groove form the window with an unclosed bottom surface; or / and the transparent outer plate is embedded in the first mounting groove, the transparent inner plate is embedded in the second mounting groove, and the transparent bottom plate is embedded in the third mounting groove;

[0022] Alternatively, a first limiting groove is provided on the bottom of the outer cylinder near the inner cylinder, and a second limiting groove is provided on the bottom of the inner cylinder near the outer cylinder. Two protrusions are provided on the annular base plate, which respectively engage with the first limiting groove and the second limiting groove. A gap is reserved between the protrusions and the groove wall of the second limiting groove to adjust the flatness between the annular base plate and the outer cylinder and the inner cylinder. Welding material is filled in the gap to fix the inner cylinder to the annular base plate.

[0023] Furthermore, in the test apparatus for a nuclear reactor flow field test, preferably the transparent outer plate, the transparent inner plate, the transparent bottom plate, and the branch pipe inlet pipe are integrally formed.

[0024] Furthermore, in the test apparatus for a nuclear reactor flow field test, preferably the plurality of pressure strips are respectively installed on the outer wall surface of the outer cylinder and the inner wall surface of the inner cylinder, and respectively extend to cover the outer wall surface of the transparent outer plate and the inner wall surface of the transparent inner plate;

[0025] Alternatively, the plurality of pressure strips are spaced apart on the side near the transparent body.

[0026] Furthermore, in the test apparatus for nuclear reactor flow field testing, preferably, sealing grooves are provided on the outer peripheral sides of both the transparent outer plate and the transparent inner plate, and sealing strips are provided in the sealing grooves;

[0027] Alternatively, a silicone pad may be provided between the plurality of pressure strips and the transparent outer panel and / or the transparent inner panel.

[0028] A sealing method for a test apparatus for a nuclear reactor flow field test, S1, involves opening a window in the cylinder with a special shape that can disperse a single square force or a force in a limited direction into forces in other directions, and having an opening at the bottom.

[0029] S2, the transparent window is sealed and installed inside the window by a sealing assembly.

[0030] Furthermore, in the sealing method of the test device for the nuclear reactor flow field test, preferably in S1-1, the length of the window of the special shape increases sequentially from top to bottom;

[0031] S2-1, a plurality of pressure strips of the sealing assembly cover the edge of the window and extend to the edge of the transparent window to radially press and fix the transparent window;

[0032] S2-2, the two support plates of the sealing assembly cover both sides of the opening and extend upward to support the bottom of the transparent window. The upward supporting force is radially dispersed in other directions of the transparent window to make the contact between the transparent window and the window more tight.

[0033] The present invention has the following advantages: by embedding the transparent window into the cylinder and pressing it to achieve a seal, on the one hand, it ensures that the flow channel inside the cylinder is not changed due to the addition of the transparent window, and on the other hand, it can monitor the flow inside the cylinder from multiple directions, providing conditions for measuring the flow field inside the cylinder, especially on the wall or near the intersection of the transparent window and the branch pipe. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0035] Figure 1 This is a first-view structural schematic diagram of a test apparatus for a nuclear reactor flow field test according to some embodiments of the present invention;

[0036] Figure 2 yes Figure 1 The diagram shows another perspective of the structure;

[0037] Figure 3 yes Figure 1 The diagram shows a longitudinal sectional view of the structure.

[0038] Figure 4 yes Figure 1 The diagram shown is a breakdown of the structure.

[0039] Figure 5 yes Figure 4 A schematic diagram of the combined structure of the cylindrical body and sealing assembly is shown.

[0040] Figure 6 yes Figure 5 The diagram shows another perspective of the structure;

[0041] Figure 7 yes Figure 5 The exploded structural diagram of the cylinder shown is shown.

[0042] Figure 8 yes Figure 5 A magnified structural diagram of point C is shown below;

[0043] Figure 9 yes Figure 4 The diagram shows the structure of the transparent window.

[0044] Figure 10 yes Figure 4 The diagram shows the structure of the main entry components.

[0045] Figure 11 yes Figure 4 The diagram shows the structure of the cap assembly. Detailed Implementation

[0046] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0047] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0048] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0049] The technical solution adopted by this invention to solve its technical problem is:

[0050] like Figures 1 to 3 As shown, some embodiments of the present invention disclose a test apparatus for nuclear reactor flow field testing. In some embodiments, this test apparatus may include: a cylinder 10, a transparent window 20, a sealing assembly 30, a main flow inlet assembly 40, a branch pipe 50, and a cylinder cover assembly 70. The cylinder 10 has an annular fluid cavity 110, and the lower part of the side wall of the cylinder 10 has an open window 14 (see reference). Figure 4 The transparent window 20 is sealed within the window 14, and a visualization cavity 210 is formed inside the transparent window 20. The fluid annular cavity 110 communicates with the visualization cavity 210 (please refer to...). Figure 3The transparent window 20 is fixed within the window 14 without affecting the original flow characteristics of the fluid. A sealing assembly 30 covers the edge of the window 14 and extends to the wall of the cylinder 10 to fix the transparent window 20 within the window 14. A main flow inlet assembly 40 is disposed on the cylinder 10 and communicates with the fluid annular cavity 110 for the entry of a large flow (main flow) of liquid. A branch pipe 50 is disposed on the transparent window 20 and communicates with the visualization cavity 210 for the entry of a small flow (branch) of liquid. A cylinder cover assembly 70 covers the opening at the top of the cylinder 10. This invention allows for observation of the smooth distribution of the branch entering the cylinder 10 and its mixing with the main flow through the transparent window 20 from the outside in, from the inside out, and from the bottom up.

[0051] Furthermore, a sealing assembly 30 is used to press and seal the transparent window 20 onto the cylinder 10, and the unidirectional pressing force is converted and dispersed into a multi-directional force, which solves the problem of the transparent window 20 sealing failure and prevents the fluid inside the cylinder 10 from leaking from the seal between the transparent window 20 and the cylinder 10.

[0052] It should be noted that the radius of curvature of the wall of the fluid annular cavity 110 is the same as that of the wall of the visualization cavity 210, and the radius of curvature of the bottom of the fluid annular cavity 110 is the same as that of the bottom of the visualization cavity 210, and they are on the same horizontal plane, so that the walls of the fluid annular cavity 110 and the visualization cavity 210 can transition smoothly and maintain a continuous arc surface.

[0053] like Figure 4 and Figure 7 As shown, in some embodiments, the cylinder 10 may include an outer cylinder 11, an inner cylinder 12, an annular bottom plate 13, and a cylinder cover assembly 70. The inner cylinder 12 is disposed inside the outer cylinder 11, and the annular bottom plate 13 is installed at the bottom of the outer cylinder 11 and the inner cylinder 12. The outer cylinder 11, the inner cylinder 12, and the annular bottom plate 13 together define a fluid annular cavity 110. The cylinder cover assembly 70 covers the openings at the top of the outer cylinder 11 and the inner cylinder 12. The aforementioned window 14 is formed on the outer cylinder 11, the inner cylinder 12, and the annular bottom plate 13. Understandably, the fluid annular cavity 110 has an annular structure, and the main flow and tributaries flow in annular mixing within the fluid annular cavity 110.

[0054] Continue to refer to Figure 7 In some embodiments, the outer cylinder 11 may have a first mounting groove 111, and the two apex corners of the first mounting groove 111 are rounded. The lateral width of the first mounting groove 111 increases from top to bottom. A first limiting groove 112 is provided on the bottom of the outer cylinder 11 near the inner cylinder 12. It can be understood that the first mounting groove 111 has a wedge-shaped structure, or in other words, the first mounting groove 111 has a trapezoidal structure. Of course, the first mounting groove 111 can also be conical, semi-elliptical, etc.

[0055] Refer again Figure 7In some embodiments, the inner cylinder 12 may have a second mounting groove 121, and the two apex corners of the second mounting groove 121 are rounded. A second limiting groove 125 is provided on the bottom of the inner cylinder 12 near the outer cylinder 11. The lateral width of the second mounting groove 121 increases from top to bottom, and the second mounting groove 121 corresponds radially to the first mounting groove 111. It can be understood that the second mounting groove 121 has a conical structure, or in other words, a trapezoidal structure. The second mounting groove 121 has the same shape and size as the first mounting groove 111. Of course, in other embodiments, the second mounting groove 121 may also be conical, semi-elliptical, etc.

[0056] For reference Figure 3 In some embodiments, the inner cylinder 12 has multiple water inlet slots 122 circumferentially formed on the upper side wall. A partition plate 123 is installed inside the inner cylinder 12, and the horizontal height of the partition plate 123 is lower than that of the water inlet slots 122. A water outlet cavity 124 is formed between the interior of the inner cylinder 12 and the partition plate 123. The water inlet slots 122 connect the fluid annular cavity 110 and the water outlet cavity 124. The fluid in the fluid annular cavity 110 enters the water outlet cavity 124 through the water inlet slots 122.

[0057] Refer again Figure 7 and Figure 8 In some embodiments, the annular base plate 13 may have a third mounting groove 131. The first mounting groove 111, the second mounting groove 121, and the third mounting groove 131 form the aforementioned unclosed bottom window 14. The annular base plate 13 also includes two protrusions 132 mounted on the top. The two protrusions 132 are respectively engaged with the first limiting groove 112 and the second limiting groove 125. A gap is reserved between the protrusions 132 and the groove wall of the second limiting groove 125 to adjust the flatness between the annular base plate 13 and the outer cylinder 11 and the inner cylinder 12. The gap is filled with welding material to fix the inner cylinder 12 to the annular base plate 13. Understandably, the protrusions 132 are connected to the outer cylinder 11 and the inner cylinder 12 by welding (welding material). The gap reserved between the protrusions 132 and the second limiting groove 125 can adjust the flatness of the wall surface between the annular base plate 13 and the outer cylinder 11 and the inner cylinder 12 during installation, reducing the deformation and other effects on the fluid annular cavity 110.

[0058] like Figure 2 and Figure 6 As shown, the annular base plate 13 has an annular structure, and a sewage discharge assembly is installed on the annular base plate 13. The sewage discharge assembly includes a sewage discharge pipe 133 installed on the annular base plate 13, which is connected to the fluid annular cavity 110. A valve is installed on the sewage discharge pipe 133. In use, the valve is opened, and impurities and dirt remaining at the bottom of the fluid annular cavity 110 can be discharged through the sewage discharge pipe 133. When not in use, the valve is closed.

[0059] like Figure 3and Figure 11 As shown, in some embodiments, the cylinder cover assembly 70 may include a cover body 71 that covers the openings at the top of the outer cylinder 11 and the inner cylinder 12. An outlet pipe 72 is mounted on the cover body 71, and the water outlet chamber 124 is connected to the outlet pipe 72. Understandably, fluid in the fluid annular cavity 110 enters the water outlet chamber 124 through the water inlet 122, and then the fluid in the water outlet chamber 124 is discharged through the outlet pipe 72.

[0060] In some embodiments, the cover 71 has multiple exhaust valves 73 arranged circumferentially on its top. These exhaust valves 73 are connected to the fluid annular cavity 110 to guide air flow, removing impurities such as air bubbles from the fluid annular cavity 110 and preventing interference with visual observation. Specifically, four exhaust valves 73 are evenly distributed circumferentially. Of course, in other embodiments, one, two, three, five, etc., of the exhaust valves 73 may be provided; the number is not limited here. Regardless of the number of exhaust valves 73 provided, they are all within the protection scope of this application.

[0061] In some embodiments, the cover 71 is also provided with a lifting lug 74 at its top, which is mainly used for lifting and moving the cylinder 10. A lifting device can be hooked onto the lifting lug 74 to move it. Of course, other handling equipment can also be used to move it. Moving is a technique well known to those skilled in the art and will not be described in detail here.

[0062] like Figure 2 and Figure 9 As shown, the transparent window 20 includes a transparent body 21 sealed within the window 14 and a branch inlet pipe 22 disposed on the transparent body 21. Both the transparent body 21 and the branch inlet pipe 22 are made of transparent material. The branch flows into the visualization cavity 210 through the branch inlet pipe 22, and the flow field when the branch flows into the visualization cavity 210 can be observed.

[0063] For reference Figure 1 A branch pipe 50 is also connected to the branch inlet pipe 22. The left side area of ​​the branch inlet pipe 22 is relatively large, which retains the tangential visualization view of the fluid in the visualization cavity 210. A rough flow field observation can be performed through the transparent outer plate 211 with an arc surface structure. Equipped with a light compensation structure, it can be used for more precise and specific observation of the internal flow field by particle imaging and other technologies.

[0064] Continue to refer to Figure 3 and Figure 9The transparent body 21 includes a transparent outer plate 211, a transparent inner plate 212, and a transparent bottom plate 213. The transparent bottom plate 213 is installed at the bottom of the transparent outer plate 211 and the transparent inner plate 212. The transparent outer plate 211, the transparent inner plate 212, and the transparent bottom plate 213 together define the visualization cavity 210. Understandably, the transparent body 21 has a U-shaped longitudinal section, and the aforementioned visualization cavity 210 is formed within it. The visualization cavity 210, together with the fluid annular cavity 110, forms an annular flow channel. Understandably, the transparent body 21 enables fluid observation of the visualization cavity 210 and the branch inlet pipe 22 region in multiple directions: outside to inside, inside to outside, and bottom to top.

[0065] For reference Figure 6 The two top corners of the transparent outer panel 211 and the two top corners of the transparent inner panel 212 are both rounded. The two top corners of the transparent outer panel 211 match the two top corners of the first mounting groove 111, and the transparent outer panel 211 is embedded in the first mounting groove 111. The two top corners of the transparent inner panel 212 match the two top corners of the second mounting groove 121, and the transparent inner panel 212 is embedded in the second mounting groove 121. The transparent bottom panel 213 is embedded in the third mounting groove 131.

[0066] Refer again Figure 9 In some embodiments, both the transparent outer plate 211 and the transparent inner plate 212 have sealing grooves 214 on their outer peripheral sides, and sealing strips 215 are provided in the sealing grooves 214. Understandably, the outer peripheral sidewall of the transparent window 20 is pressed and sealed with the window wall of the window 14 using the sealing strip 215 to prevent hard contact between the metal cylinder 10 and the transparent window 20, thus avoiding localized stress concentration caused by hard contact. The window 14 is designed and machined with the axis of the cylinder 10 as the center. The cross-section of the window 14 faces radially toward the axis, forming a fan shape with the line connecting it to the axis. When the sealing assembly 30 on the outside of the outer cylinder 11 is pressed, the transparent window 20 is subjected to pressure toward the axis, and the sealing strip 215 is simultaneously deformed in the same direction, thereby achieving radial auxiliary sealing. Simultaneously, the sealing surface on the inner cylinder 12 (the groove wall of the second mounting groove 121) can essentially achieve self-sealing.

[0067] In some embodiments, minor variations in the machining of the sealing groove 214 can be compensated for by adding soft fillers such as sealant grease or silicone within the sealing groove 214. The sealing strip 215 can be made of soft materials such as rubber or silicone.

[0068] Following another reference Figure 9In some embodiments, the transparent outer panel 211, transparent inner panel 212, transparent bottom panel 213, and branch pipe inlet pipe 22 are integrally formed and can be made of highly transparent materials such as plexiglass and quartz. Of course, in other embodiments, the transparent outer panel 211, transparent inner panel 212, transparent bottom panel 213, and branch pipe inlet pipe 22 can also be manufactured separately and then assembled together using techniques such as bonding.

[0069] In other embodiments, the intersection lines of the transparent outer plate 211 and the transparent inner plate 212 with the transparent bottom plate 213 are respectively provided with rounded corners to reduce stress concentration in the window and improve light transmission, strength and temperature resistance.

[0070] In related experiments, the cylinder 10 was large in size and had a large fluid volume. No refractive index matching fluid was used. During the use of the visualization device, the focus was on pressure drop rather than pressure value, and on the flow channel size. To observe the flow field at the inlet of the branch pipe 22 and retain the specific flow channel structure, the two apex corners of window 14 were not rounded. Multiple transparent windows 20 made of bonded (or fused) acrylic glass, a set of one-piece molded quartz transparent windows 20, and a set of stainless steel transparent windows 20 (opaque, collectively referred to as transparent windows 20) were manufactured according to different purposes. The bonded acrylic glass transparent window 20 cracked during the pressure holding process after the static pressure slowly reached 0.30 MPa (the curved seal remained good). The one-piece molded quartz transparent window 20 could withstand pressures of 0.27 MPa and 900 m... 3 Under conditions of continuous flow rate and circumferential impact, the stainless steel transparent viewing window 20 can operate for extended periods at 0.63 MPa, 80℃, and 900m. 3 It has been operating stably for a long time under the circumferential impact of a flow rate of / h.

[0071] The implementation process compared the sealing methods of silicone pad sealing to rubber strip sealing and grease sealing. The method of using silicone pad to fill the space between the transparent window 20 and the window wall of window 14 to eliminate hard contact is called wide surface sealing, while the method of using rubber strip sealing is called narrow surface sealing. Wide surface sealing is more affected by the dimensional deviation of the sealing surface and the uneven load at various points on the curved surface, and the upper limit of sealing pressure is not as good as narrow surface sealing.

[0072] like Figure 5 and Figure 6As shown, in some embodiments, the sealing assembly 30 may include multiple pressure strips 31 and support plates 32. The multiple pressure strips 31 cover the front and rear edges of the window 14 and extend to the wall of the cylinder 10. Understandably, the multiple pressure strips 31 are respectively installed on the outer wall of the outer cylinder 11 and the inner wall of the inner cylinder 12 by bolts, screws, etc. The pressure strips 31 installed on the outer cylinder 11 press inward from the outer wall to the edge of the transparent body 21, and the pressure strips 31 installed on the inner cylinder 12 press inward from the inside to the edge of the transparent body 21; the transparent body 21 is clamped and fixed by the pressing force in both the outward and inward directions.

[0073] The multi-segment manufacturing of the pressure strip 31 is used to solve the problems of incompatibility of clamping forces in different directions and uneven clamping forces required at each clamping point when sealing curved surfaces. It can also eliminate the influence of residual stress on the deformation tendency of the complex curved surface pressure strip 31 structure. The pressure strip 31 installed on the outer cylinder 11 is mainly used to align the transparent body 21 with the wall surface of the outer cylinder 11, limit the local deformation of the transparent body 21, and play an auxiliary sealing role.

[0074] For reference Figure 8 In some embodiments, the sealing assembly 30 may further include two support plates 32 respectively covering both sides of the opening of the window 14 to support the bottom of the transparent body 21 upwards and extend to the bottom of the cylinder 10. Understandably, the two support plates 32 are installed on both sides of the third mounting groove 131 at the bottom of the wake-up base plate 13 and extend upwards to support the transparent body 21, providing an upward supporting force to the transparent body 21. This upward supporting force is converted into a pressing force on the transparent body 21 in other directions, generating a normal pressure component in each local area of ​​each outer peripheral surface of the transparent body 21. This results in better sealing of the transparent body 21 at the window 14 of the curved structure, meeting more demanding visualization structural requirements.

[0075] It should also be noted that the narrow-face seal of the sealing strip 215 has a smaller contact area compared to the wide-face seal gasket. When the same sealing pressure applied to the pressure strip 31 is transmitted to the sealing strip 215 in the sealing groove 214, the resulting pressure is greater, thus improving the reliability and pressure of the seal. Since there are precision deviations in the machining of any window 14's perimeter, the fine control of spatial curved surfaces is not as effective as that of flat or regular curved surfaces. Therefore, the larger sealing strip 215 compensates for these precision deviations through differences in the degree of compression, thereby saving on precision machining costs.

[0076] Refer again Figure 8 A silicone pad 33 is provided between multiple pressure strips 31 and the transparent outer panel 211 and / or the transparent inner panel 212. When the pressure strips 31 are pressed against the transparent body 21, it prevents uneven stress from damaging the transparent body 21.

[0077] Continue to refer to Figure 6 Multiple pressure strips 31 are spaced apart on the side near the transparent body 21 with grooves 311. In other words, the thickness between the wall of the cylinder 10 and the transparent body 21 can be measured through the grooves 311, thereby evaluating the flow channel alignment effect between the fluid annular cavity 110 and the visualization cavity 210.

[0078] like Figure 4 and Figure 10 As shown, in some embodiments, the main inlet assembly 40 may include a connecting pipe section 41, a rectifier pipe section 42, and a connecting pipe section 43 connected in sequence. The connecting pipe section 41 is disposed on the cylinder 10, and the rectifier pipe section 42 is provided with a rectifier grid 44 for smooth fluid flow. The connecting pipe section 43 realizes the transition connection between the cylinder 10 and the external circuit. The external circuit can use a standard pipe with a standard-sized corrugated pipe. The size is inconsistent with the circuit-side interface size of the connecting pipe section 41, and the connection size transition is realized through the connecting pipe section 43. The rectifier grid 44 disposed inside the rectifier pipe section 42 enables the fluid to quickly enter a smooth flow state, shortening the pipeline and saving space.

[0079] A sealing method for a test apparatus for a nuclear reactor flow field test, S1, involves opening a window 14 on the cylinder 10 with a special shape that can disperse a single square force or a limited directional force into forces in other directions, and having an opening at the bottom.

[0080] S1-1, the length of the specially shaped window 14 increases sequentially from top to bottom.

[0081] By setting the transparent window 20 into a wedge-shaped structure that is narrower at the top and wider at the bottom, the unidirectional force can be transmitted through the transparent window 20 to other peripheral surfaces of the transparent window 20, generating a normal pressure component in each local part of its peripheral surface.

[0082] Therefore, S1 can also be changed to provide a transparent window 20 of a special shape that can disperse a force acting in a single direction or a force acting in a limited direction to other directions, and to open a window 14 of the same shape on the wall of the cylinder 10.

[0083] S2, the transparent window 20 is sealed and installed inside the window 14 by the sealing assembly 30. The support plate 32 of the sealing assembly 30 applies an upward force to both sides of the bottom of the transparent window 20 to change the upward supporting force of the transparent window 20 into a radial analytical force, so as to make the contact between the transparent window 20 and the window wall of the window 14 of the cylinder 10 tighter.

[0084] S2-1, a plurality of pressure strips 31 of the sealing assembly 30 cover the edge of the window 14 and extend to the edge of the transparent window 20 to hold and fix the transparent window 20 in a radial manner.

[0085] S2-2, the two support plates 32 of the sealing assembly 30 cover both sides of the opening and extend upward to support the bottom of the transparent window 20. The upward support force is distributed radially in other directions of the transparent window 20 so that the contact between the transparent window 20 and the window 14 is tighter.

[0086] It should be noted that those skilled in the art can freely combine the above-mentioned technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention.

Claims

1. A test apparatus for nuclear reactor flow field testing, characterized in that, include: The cylindrical body (10) is provided with an annular fluid cavity (110), and the lower part of the side wall of the cylindrical body (10) is provided with a window (14) with an unclosed bottom surface; A transparent window (20) includes a transparent body (21) sealed within the window (14) and a branch inlet pipe (22) disposed on the transparent body (21). The transparent body (21) has a U-shaped longitudinal section and forms a visualization cavity (210) inside. The branch inlet pipe (22) is connected to the visualization cavity (210). The fluid annular cavity (110) is connected to the visualization cavity (210) without affecting the original flow characteristics of the fluid. This enables fluid observation of the region of the visualization cavity (210) and the branch inlet pipe (22) from multiple directions, including from the outside to the inside, from the inside to the outside, and from the bottom to the top of the transparent body (21).

2. The test apparatus for nuclear reactor flow field testing according to claim 1, characterized in that, The test apparatus for the nuclear reactor flow field test also includes a sealing assembly (30) detachably mounted on the cylinder (10) for sealing the transparent body (21) to the window (14). The sealing assembly (30) includes a pressure strip (31) covering the front and rear edges of the window (14) and extending to the wall of the cylinder (10) to fix the circumferential edge of the transparent body (21); or / and the sealing assembly (30) also includes two support plates (32) covering the two sides of the opening of the window (14) to support the bottom of the transparent body (21) upwards and extending to the bottom of the cylinder (10).

3. The test apparatus for nuclear reactor flow field testing according to claim 2, characterized in that, The cylindrical body (10) is also equipped with a main flow inlet assembly (40) that communicates with the fluid annular cavity (110) so that fluid enters the fluid annular cavity (110); the main flow inlet assembly (40) includes a pipe section (41), a rectifier pipe section (42) and a connecting pipe section (43) connected in sequence. The pipe section (41) is disposed on the cylindrical body (10), and the rectifier pipe section (42) is provided with a rectifier grid (44) for making the fluid flow smoothly. Alternatively, a branch pipe (50) may also be connected to the branch inlet pipe (22).

4. The test apparatus for nuclear reactor flow field testing according to claim 1, characterized in that, The radius of curvature of the wall of the fluid annular cavity (110) is the same as that of the wall of the visualization cavity (210), and the radius of curvature of the bottom of the fluid annular cavity (110) is the same as that of the bottom of the visualization cavity (210) and they are on the same horizontal plane, so that the wall of the fluid annular cavity (110) and the wall of the visualization cavity (210) can transition smoothly.

5. The test apparatus for nuclear reactor flow field testing according to claim 1, characterized in that, The horizontal width of the transparent body (21) increases from top to bottom, and / or the top corners on both sides of the transparent body (21) are rounded. The shape of the window (14) matches the shape of the transparent body (21).

6. The test apparatus for nuclear reactor flow field testing according to claim 3, characterized in that, The cylinder (10) includes an outer cylinder (11), an inner cylinder (12), and an annular bottom plate (13). The inner cylinder (12) is disposed inside the outer cylinder (11), and the annular bottom plate (13) is installed at the bottom of the outer cylinder (11) and the inner cylinder (12). The outer cylinder (11), the inner cylinder (12), and the annular bottom plate (13) together define the fluid annular cavity (110). Or / and the transparent body (21) includes a transparent outer plate (211), a transparent inner plate (212) and a transparent bottom plate (213), the transparent bottom plate (213) being installed at the bottom of the transparent outer plate (211) and the transparent inner plate (212), the transparent outer plate (211), the transparent inner plate (212) and the transparent bottom plate (213) together defining the visualization cavity (210).

7. The test apparatus for nuclear reactor flow field testing according to claim 6, characterized in that, The outer cylinder (11) has a first mounting groove (111), the inner cylinder (12) has a second mounting groove (121), and the annular bottom plate (13) has a third mounting groove (131). The first mounting groove (111), the second mounting groove (121), and the third mounting groove (131) form the window (14) with an unclosed bottom surface; or / and the transparent outer plate (211) is embedded in the first mounting groove (111), the transparent inner plate (212) is embedded in the second mounting groove (121), and the transparent bottom plate (213) is embedded in the third mounting groove (131). Alternatively, a first limiting groove (112) is provided on the bottom of the outer cylinder (11) near the inner cylinder (12), and a second limiting groove (125) is provided on the bottom of the inner cylinder (12) near the outer cylinder (11). Two protrusions (132) are provided on the annular base plate (13) respectively, which are fitted into the first limiting groove (112) and the second limiting groove (125). A gap is reserved between the protrusions (132) and the groove wall of the second limiting groove (121) to adjust the flatness between the annular base plate (13) and the outer cylinder (11) and the inner cylinder (12). Welding material is filled in the gap to fix the inner cylinder (12) and the annular base plate (13).

8. The test apparatus for nuclear reactor flow field testing according to claim 6, characterized in that, The transparent outer plate (211), the transparent inner plate (212), the transparent bottom plate (213), and the branch pipe inlet pipe (22) are integrally formed.

9. The test apparatus for nuclear reactor flow field testing according to claim 6, characterized in that, The plurality of pressure strips (31) are respectively installed on the outer wall surface of the outer cylinder (11) and the inner wall surface of the inner cylinder (12), and respectively extend to cover the outer wall surface of the transparent outer plate (211) and the inner wall surface of the transparent inner plate (212); Alternatively, the plurality of pressure strips (31) are all provided with serrations (311) at intervals on the side of the transparent body (21) near the pressure strips (31).

10. The test apparatus for nuclear reactor flow field testing according to claim 6, characterized in that, Both the outer and inner transparent panels (211 and 212) are provided with sealing grooves (214), and a sealing strip (215) is provided in the sealing grooves (214). Alternatively, a silicone pad (33) may be provided between the plurality of pressure strips (31) and the transparent outer panel (211) or / and the transparent inner panel (212).

11. A sealing method for a test apparatus for a nuclear reactor flow field test, the test apparatus for a nuclear reactor flow field test according to any one of claims 1-10, characterized in that, S1, A window (14) with a special shape that can disperse a single square force or a limited directional force into other directional forces is opened on the cylinder (10) and has an opening at the bottom; S2, the transparent window (20) is sealed and installed inside the window (14) by the sealing assembly (30).

12. The sealing method for the test apparatus of the nuclear reactor flow field test according to claim 11, characterized in that, S1-1, the length of the special-shaped window (14) increases sequentially from top to bottom; S2-1, a plurality of pressure strips (31) of the sealing assembly (30) cover the edge of the window (14) and extend to the edge of the transparent window (20) to hold and fix the transparent window (20) in a radial manner; S2-2, the two support plates (32) of the sealing assembly (30) cover both sides of the opening and extend upward to support the bottom of the transparent window (20). The upward support force is radially dispersed in other directions of the transparent window (20) so that the contact between the transparent window (20) and the window (14) is closer.

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