Test method of pipe explosion simulation device based on fluid blocking test

Abstract

The invention belongs to the technical field of fluid blocking tests, and particularly relates to a test method of a pipe explosion simulation device based on a fluid blocking test. The tube bursting simulation device comprises an outer tube body and a crushing diaphragm located in a tube cavity of the outer tube body, the tube bursting simulation device further comprises a bursting disc, the bursting disc and the crushing diaphragm are sequentially arranged along the tube cavity of the outer tube body, and therefore a closed pressure adjusting cavity is formed in the portion, between the bursting disc and the crushing diaphragm, of the tube cavity of the outer tube body. The pressure adjusting cavity is communicated with a pressure air source or a pressure liquid source through a flow channel penetrating through the pipe wall of the outer pipe body. The device has higher controllability on pipe explosion pressure and pipe explosion time, and has the advantages of simplicity, convenience and rapidness in use and compact and reasonable structure.

Description

[0001] The present invention is a divisional application of application number CN202210275742.X, whose application name is “A pipe burst simulation device based on fluid blocking test and its test method”. The application date of the original application is March 21, 2022. Technical Field

[0002] The invention belongs to the technical field of fluid blocking tests, and in particular relates to a test method of a pipe burst simulation device based on a fluid blocking test. Background Art

[0003] The fluid blocking test is designed to determine the key performance parameters of the check valve, verify the ability of the valve to shut down urgently after reverse flow occurs under the condition of a pipe burst loss of water accident in a nuclear power plant, and make a sufficiently conservative estimate of the pipeline pressure fluctuation level caused by the instantaneous closure of the valve. In the fluid blocking test, a pipe burst simulation device is required to achieve the loss of water spraying requirements. The basic principle of the traditional pipe burst simulation device is to use a certain diaphragm and fix the diaphragm between the air inlet outlet and the high-pressure air supply pipeline. The instantaneous high pressure causes the diaphragm to rupture and form a hammer shock wave, thereby achieving the impact purpose. However, due to the real pipe burst accident, the initial loss of water spraying time is about milliseconds. The pipe burst simulation devices used in the existing public fluid blocking test technology are all conventional single diaphragm structures, with slow action time and difficult to control pipe burst time. Obviously, they cannot meet the millisecond-level test requirements and need to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a test method for a pipe burst simulation device based on a fluid blocking test, which has stronger controllability over the pipe burst pressure and pipe burst time, and has the advantages of being easy and quick to use and having a compact and reasonable structure.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A test method for a pipe burst simulation device based on a fluid blocking test, characterized in that: the pipe burst simulation device comprises an outer pipe body and a crushed diaphragm located in a tube cavity of the outer pipe body, and further comprises a bursting disc, wherein the bursting disc and the crushed diaphragm are arranged in sequence along the tube cavity of the outer pipe body, so that a closed pressure regulating chamber is formed between a section of the tube cavity of the outer pipe body between the bursting disc and the crushed diaphragm, and the pressure regulating chamber is connected to a pressure gas source or a pressure liquid source through a flow channel penetrating through a tube wall of the outer pipe body;

[0007] The end of the outer tube body is used as the bottom end of the outer tube body, and the crushed diaphragm, diaphragm pressure ring, disc spring, spring base and diaphragm support ring are coaxially arranged in sequence from the bottom end to the head end along the axial direction of the outer tube body; the spring base is fixed on the inner wall of the outer tube body, and the diaphragm support ring is fixed on the spring base; an extension tube is coaxially extended downward on the diaphragm support ring, the inner wall of the extension tube constitutes a bursting flow channel, and the diaphragm pressure ring is coaxially sleeved on the outer wall of the extension tube; the top end of the disc spring is tightly pressed against the spring base, and the bottom end of the disc spring and the diaphragm pressure ring are pressed against each other, so that the diaphragm pressure ring is elastically pressed down on the upper surface of the crushed diaphragm;

[0008] The test steps are as follows:

[0009] The inlet pressure of the burst pipe simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the preload force of the disc spring is F, the rupture pressure of the crushed diaphragm is P, and the bursting pressure of the bursting disc is P', where P = P';

[0010] At the beginning of the test, the pressure in the pressure regulating chamber is P2=P. At this time, the pressure acting on the bursting disc is P2-P3=P, and the pressure acting on the crushed diaphragm is P1-P2=PP=P; the crushed diaphragm and the bursting disc are both kept in a stable state.

[0011] Adjust the pressure in the pressure regulating chamber to P2>P=P′, the bursting disc explodes, P2=P3=0, and the pressure acting on the crushed diaphragm is P1-P2=P. The crushed diaphragm pushes the diaphragm pressure ring axially, causing the disc spring to bend and deform until the disc spring moves to the failure position. At this time, the spring force instantly drops to 0, and at the same time, the ring groove is weakened and moves to the position of the diaphragm support ring and produces local plastic deformation, causing the crushed diaphragm to rupture.

[0012] Preferably, an inner flange-shaped closing opening is provided at the bottom end of the outer tube body, and the inlet ring cover is fixed at the closing opening from bottom to top, and the inlet ring cover cooperates with the closing opening to clamp and crush the outer edge of the diaphragm.

[0013] Preferably, there is a fitting gap between the outer ring surface of the diaphragm pressure ring and the closing end, and a weakening ring groove with a circular notch facing downward is coaxially recessed on the crushed diaphragm at the fitting gap; when the bottom ring surface of the diaphragm pressure ring is elastically pressed down on the crushed diaphragm, a reserved channel is present between the crushed diaphragm and the inlet ring cover for the medium to enter the weakening ring groove cavity.

[0014] Preferably, the diaphragm support ring has an outer shape of a two-stage stepped sleeve, the large diameter section of the diaphragm support ring constitutes a mating section that is threaded with the spring base, and the small diameter section of the diaphragm support ring constitutes the extension tube; the cylinder cavity of the large diameter section is in the shape of a trumpet hole that is thick at the top and thin at the bottom, thereby forming an expansion cone flow channel structure together with the trumpet hole-shaped cylinder cavity that is thick at the top and thin at the bottom of the spring base.

[0015] Preferably, the trumpet-shaped barrel cavity of the spring base is a two-stage variable-diameter hole, including an upper trumpet section located at the top and a lower trumpet section whose bottom aperture matches that of the upper trumpet section; on the axial cross-section of the outer tube body, the barrel cavity of the large diameter section forms an angle of 55° with the center line of the bursting flow channel, the hole wall of the small trumpet hole at the spring base forms an angle of 35° with the center line of the bursting flow channel, and the hole wall of the large trumpet hole forms an angle of 10° with the center line of the bursting flow channel.

[0016] Preferably, the disc spring is of an external slotted structure; a T-slot is radially recessed on the annular wall of the disc spring, the two sections of the T-slot have equal depths, and the width of the outer slot at the slot mouth is twice the width of the inner slot at the slot bottom, the ratio of the disc spring height dimension H to the thickness dimension h is H / h≥3, and the load-displacement curve presents a nonlinear negative stiffness characteristic.

[0017] Preferably, the crushed diaphragm is a corrugated metal diaphragm.

[0018] Preferably, an outlet ring cover is coaxially arranged at the top end of the outer tube body, and an upper pressure ring is coaxially arranged on the outlet ring cover so as to clamp and fix the bursting disc at the outlet ring cover.

[0019] The beneficial effects of the present invention are:

[0020] 1) Through the above scheme, the present invention uses the bursting disc as the active rupture part and the crushed diaphragm as the passive rupture part, thereby achieving a controllable pipe bursting effect; more importantly, by setting the middle cavity, that is, the regulating cavity, during operation, by filling the pressure regulating cavity with high-pressure medium, when the pressure regulating cavity is pressurized to the required test pressure, that is, the bursting disc rupture pressure, the bursting disc is opened and ruptured at the same time, and the pressure in the pressure regulating cavity is instantly released to the atmospheric pressure. Under the action of the pressure difference, the crushed diaphragm is displaced accordingly, and the local plastic deformation is weakened at the ring, the crushed diaphragm is ruptured, and the pipe bursting condition is generated, and the operation is extremely convenient and reliable.

[0021] Thus, the present invention has the advantages of being easy and quick to use and having a compact and reasonable structure. It has stronger controllability over the bursting pressure and bursting time, and the bursting time is more accurate, and can be applied to various bursting water loss test occasions.

[0022] 2) On the basis of the above structure, the present invention is also provided with a disc spring, so as to cooperate with the aforementioned adjustment chamber, further realizing the purpose of accurate control of test parameters such as bursting pressure and millisecond bursting time. Specifically, due to the existence of the disc spring, on the one hand, before the test, the disc spring can rely on its own elastic force to ensure that the hard pressure of the diaphragm pressure ring on the crushed diaphragm is transformed into a relatively flexible elastic pressure. At this time, the disc spring can achieve the self-balancing effect of the force of the entire diaphragm system, which provides a basic guarantee for the accuracy of subsequent bursting data. On the other hand, during the test, when the crushed diaphragm is deformed and finally ruptured, the diaphragm pressure ring is pressed upward, pushing the disc spring to deform, so that the disc spring is instantly switched from the original pressure state to the failure state, that is, the elastic force becomes zero; this can effectively eliminate the possible influence of the existence of the disc spring on the bursting test, thereby further ensuring the accuracy of the subsequent bursting data, with significant results.

[0023] 3) The pipe burst simulator described in the present invention can reasonably select the middle cavity gas pressurization test method or the liquid pressurization test method according to different test valve types and test parameter requirements. The test method is simple, easy to operate, and flexible. At the same time, the secondary bursting disc used in the device has no fixed structural requirements and restrictions, and can be flexibly adjusted and selected according to the parameters required for the test.

[0024] 4) The disc spring of the present invention adopts an external slotted diaphragm structure, which has a completely different design concept and use environment from the traditional diaphragm disc spring. The traditional diaphragm disc spring focuses on how to prevent buckling and self-reset and service life when designing. The ratio of its height H to thickness h is usually less than 2, and the use range of its load displacement curve is also different from that of the present invention. The external slotted diaphragm disc spring designed by the present invention focuses on its load characteristics of irreversible overload failure and negative stiffness during use. Its H / h is ≥3, and the use range of its load displacement curve is further moved forward. After a test spring fails, it is replaced immediately, which is convenient and quick to use.

[0025] 5) The spring base and the diaphragm support ring of the present invention cooperate with each other in the cylinder cavity to form a two-stage expansion cone flow channel structure, which can be applied to the burst pipe test of the flash jet flow under the saturated water and supercooled water test media, and can reduce the reverse fluid thrust caused by the burst pipe, thereby avoiding damage to the entire test pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the initial state of the pipe burst simulation device of the present invention;

[0027] Figure 2 It is a schematic diagram of the state of the pipe burst simulation device of the present invention after the pipe burst;

[0028] Figure 3 It is a structural schematic diagram of an expansion cone flow channel structure;

[0029] Figure 4 It is a cross-sectional view of a disc spring;

[0030] Figure 5 It is a top view of the disc spring;

[0031] Figure 6 This is the load-displacement curve of the disc spring.

[0032] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0033] 10-outer tube body 11-closed

[0034] 20-crush the diaphragm 21-weaken the ring groove

[0035] 30-bursting disc 40-diaphragm pressure ring 50-disc spring 51-T-slot

[0036] 60-spring base 70-diaphragm support ring 71-extension tube

[0037] 80-inlet ring cover 90-outlet ring cover 91-upper pressure ring DETAILED DESCRIPTION

[0038] For ease of understanding, here we combine Figure 1-6 The specific structure and working mode of the present invention are further described as follows:

[0039] The specific structure of the pipe burst simulation device of the present invention is as follows Figure 1-2 As shown, the outer tube body 10 is used as a carrier, and the bottom end surface of the outer tube body 10 is provided with a closing mouth 11 so that the whole is formed into a plunger cylinder shape, and the outer tube body 10 is in the cylinder cavity as shown in FIG. Figure 1 As shown, the inlet ring cover 80, the crushed diaphragm 20, the diaphragm pressure ring 40, the disc spring 50, the diaphragm support ring 70 with the extension tube 71, the spring base 60, the upper pressure ring, the bursting disc 30 and the outlet ring cover 90 are arranged in order from bottom to top. Of course, as a standard part, the bursting disc 30 can reasonably select existing mature bursting disc 30 products according to the test parameters, and is not limited to a specific structural form. Among them:

[0040] During actual assembly, the inlet ring cover 80 may be provided with a flange bolt hole, and connected to the test pipe by bolts, and sealed by a metal sealing ring; different specifications of test valves can be tested by replacing different flanges of the inlet ring cover 80. The inner end surface of the inlet ring cover 80 is provided with a positioning ring surface, so that after contacting the positioning ring groove at the closing end 11 of the outer tube body, it can be connected by bolts; a sealing ring is provided at the positioning ring surface to ensure the sealing between the inlet ring cover 80 and the closing end 11.

[0041] like Figure 1-2As shown, the spring base 60 and the outer tube 10, and the diaphragm support ring 70 and the spring base 60 are all threadedly connected. The spring base 60 and the diaphragm support ring 70 are installed to form an expansion cone flow channel structure, which can be applied to the flash jet flow burst test under saturated water and supercooled water test media. Figure 3 As shown, the angle between the L1 section at the diaphragm support ring 70, i.e., the large diameter section, and the center line of the burst pipe flow channel is α=55°, the angle between the L2 section at the spring base 60, i.e., the lower horn section, and the center line of the burst pipe flow channel is β=35°, and the angle between the L3 section, i.e., the large horn hole, and the center line of the burst pipe flow channel is γ=10°. The above angle design can effectively reduce the reverse fluid thrust generated by the burst pipe, and minimize the damage to the entire test pipeline.

[0042] For the disc spring 50, its appearance is as follows Figure 4-5 As shown, the outer ring surface is provided with evenly distributed special-shaped grooves or T-shaped grooves 51, the outer length of the special-shaped groove is equal to the inner length, the outer width is twice the inner width, the ratio of the height dimension H to the thickness dimension h of the disc spring 50 is H / h≥3, and its load displacement curve presents a nonlinear negative stiffness characteristic. So far, the design of traditional diaphragm disc springs focuses on how to prevent buckling and self-reset and service life. The ratio of its height H to its thickness h is usually less than 2, and the use range of its load displacement curve is usually in Figure 6 The AB segment shown; and the disc spring 50 designed in the present invention focuses on the use of its overload failure and irreversible negative stiffness load characteristics during use, its H / h ≥ 3, the use range of its load displacement curve Figure 6 The BC section shown was replaced after the spring failed during a test. Figure 5 There are 16 special-shaped slots in the machine, and of course the number can be increased or decreased depending on the situation.

[0043] When the present invention is actually installed, the order is usually as follows: first, the crushed diaphragm 20 is welded to the closing port 11, and then the diaphragm pressure ring 40, the disc spring 50, the diaphragm support ring 70, and the spring base 60 are sequentially installed in the outer tube body 10; then, the outlet ring cover 90, the bursting disc 30, and the upper pressure ring 91 are separately installed and connected, and then the whole is connected to the outer tube body 10 by bolts, and finally the inlet ring cover 80 is connected to the outer tube body 10, so as to further clamp and fix the crushed diaphragm 20. When the crushed diaphragm 20 is designed, it is as follows Figure 1 The double arc structure shown in the figure has a first arc located in the central area and is simultaneously sleeved in the tube cavity of the extension tube 71. The root of the second arc is provided with a weakening annular groove 21 so as to produce a weakening effect when impacted. Figure 2 Deformation shown.

[0044] The test method of the present invention comprises the following steps:

[0045] The inlet pressure of the burst pipe simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the preload force of the disc spring is F, the rupture pressure of the collapsed diaphragm 20 is P, and the bursting pressure of the bursting disc 30 is P′, where P=P′;

[0046] At the beginning of the test, the pressure in the pressure regulating chamber is P2=(70%~80%)P, at which time the pressure acting on the bursting disc 30 is P2-P3=(70%~80%)P, and the pressure acting on the crushed diaphragm 20 is P1-P2=P-(70%~80%)P=(20%~30%)P; the crushed diaphragm 20 and the bursting disc 30 are both kept in a stable state;

[0047] The pressure in the pressure regulating chamber is adjusted to P2>P=P′, the bursting disc 30 explodes, P2=P3=0, and the pressure acting on the crushed diaphragm 20 is P1-P2=P. The crushed diaphragm 20 axially pushes the diaphragm pressure ring 40 to move, causing the disc spring 50 to produce buckling deformation until the disc spring 50 moves to the failure position. At this time, the spring force instantly drops to 0, and at the same time, the annular groove 21 is weakened and moves to the position of the diaphragm support ring 70 and produces local plastic deformation, and the crushed diaphragm 20 ruptures.

[0048] Of course, it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0050] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A test method for a pipe burst simulation device based on a fluid blocking test, characterized in that: The pipe burst simulation device comprises an outer pipe body (10) and a crushed diaphragm (20) located in the tube cavity of the outer pipe body (10), and also comprises a bursting disc (30), wherein the bursting disc (30) and the crushed diaphragm are arranged in sequence along the tube cavity of the outer pipe body (10), so that a closed pressure regulating chamber is formed between a section of the tube cavity of the outer pipe body (10) between the bursting disc (30) and the crushed diaphragm (20), and the pressure regulating chamber is connected to a pressure gas source or a pressure liquid source through a flow channel penetrating the tube wall of the outer pipe body (10); The end of the fixed crushing diaphragm (20) is the bottom end of the outer tube body (10), and the crushing diaphragm (20), the diaphragm pressure ring (40), the disc spring (50), the spring base (60) and the diaphragm support ring (70) are coaxially arranged in sequence from the bottom end to the head end along the axial direction of the outer tube body (10); the spring base (60) is fixed on the inner wall of the outer tube body (10), and the diaphragm support ring (70) is fixed on the spring base (60) An extension tube (71) coaxially extends downward from the diaphragm support ring, the inner wall of the extension tube (71) forms a bursting flow channel, and a diaphragm pressure ring (40) is coaxially sleeved on the outer wall of the extension tube (71); the top end of the disc spring (50) is tightly pressed against the spring base (60), and the bottom end of the disc spring (50) and the diaphragm pressure ring (40) are pressed against each other, so that the diaphragm pressure ring (40) is elastically pressed downward on the upper surface of the crushed diaphragm (20); The test steps are as follows: The inlet pressure of the pipe burst simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the disc spring preload is F, the rupture pressure of the crushed diaphragm (20) is P, and the bursting pressure of the bursting disc (30) is P′, wherein P=P′; At the beginning of the test, the pressure in the pressure regulating chamber is P2=(70%-80%)P, at which time the pressure acting on the bursting disc (30) is P2-P3=(70%-80%)P, and the pressure acting on the crushed diaphragm (20) is P1-P2=P-(70%-80%)P=(20%-30%)P; the crushed diaphragm (20) and the bursting disc (30) are both kept in a stable state; The pressure in the pressure regulating chamber is adjusted to P2>P=P′, the bursting disc (30) explodes, P2=P3=0, and the pressure acting on the crushed diaphragm (20) is P1-P2=P. The crushed diaphragm (20) axially pushes the diaphragm pressure ring (40) to move, driving the disc spring to produce buckling deformation until the disc spring (50) moves to the failure position. At this time, the spring force is instantly reduced to 0, and at the same time, the ring groove (21) is weakened and moves to the position of the diaphragm support ring and produces local plastic deformation, causing the crushed diaphragm (20) to rupture.

2. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, characterized in that: The bottom end of the outer tube body (10) is provided with an inwardly turned-edge shaped closing opening (11), and the inlet ring cover (80) is fixed on the closing opening (11) from bottom to top, and the inlet ring cover (80) cooperates with the closing opening (11) to clamp and crush the outer edge of the diaphragm (20).

3. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 2, characterized in that: There is a matching gap between the outer ring surface of the diaphragm pressure ring (40) and the closing opening (11), and a weakening ring groove (21) with a circular notch facing downward is coaxially recessed on the crushed diaphragm (20) at the matching gap; when the bottom ring surface of the diaphragm pressure ring (40) is elastically pressed down on the crushed diaphragm (20), a reserved channel is provided between the crushed diaphragm (20) and the inlet ring cover (80) for the medium to enter the groove cavity of the weakening ring groove (21).

4. A test method for a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The diaphragm support ring (70) has a two-stage stepped sleeve shape. The large diameter section of the diaphragm support ring (70) constitutes a mating section that is threadedly mated with the spring base (60), and the small diameter section of the diaphragm support ring (70) constitutes the extension tube (71). The barrel cavity of the large diameter section is in the shape of a trumpet hole that is thick at the top and thin at the bottom, thereby forming an expansion conical flow channel structure together with the trumpet hole-shaped barrel cavity that is thick at the top and thin at the bottom of the spring base (60).

5. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 4, characterized in that: The trumpet hole-shaped barrel cavity of the spring base (60) is a two-stage variable diameter hole, comprising an upper trumpet section located at the top and a lower trumpet section whose bottom aperture matches that of the upper trumpet section; on the axial cross section of the outer tube body (10), the barrel cavity of the large diameter section forms an angle of 55° with the center line of the bursting flow channel, the hole wall of the small trumpet hole at the spring base (60) forms an angle of 35° with the center line of the bursting flow channel, and the hole wall of the large trumpet hole forms an angle of 10° with the center line of the bursting flow channel.

6. A test method for a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The disc spring (50) is of an external slotted structure; a T-shaped slot (51) is radially recessed on the annular wall of the disc spring (50); the two sections of the T-shaped slot (51) have equal depths, and the width of the outer slot at the slot mouth is twice the width of the inner slot at the slot bottom; the ratio of the height dimension H to the thickness dimension h of the disc spring (50) is H / h≥3, and the load displacement curve presents a nonlinear negative stiffness characteristic.

7. A test method for a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The crushed diaphragm (20) is a corrugated metal diaphragm.

8. A test method for a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: An outlet ring cover (90) is coaxially arranged at the top end of the outer tube body (10), and an upper pressure ring (91) is coaxially arranged on the outlet ring cover (90) so as to clamp and fix the bursting disc (30) at the outlet ring cover (90).

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