Erosion-resistant conical tube and method for determining size of erosion-resistant conical tube

Abstract

The invention provides an anti-erosion conical pipe and a size determining method for the anti-erosion conical pipe, and the conical pipe comprises a first straight pipe section, a second straight pipe section, a third straight pipe section and a fourth straight pipe section which are sequentially connected in the flowing direction of fluid, and the first straight pipe section is used for being connected with an incoming flow pipe; one end of the annular pipe section is connected with the first straight pipe section, the end, away from the first straight pipe section, of the annular pipe section is folded towards the center of the annular pipe section to form a folded section, and the diameter of the annular pipe section is gradually reduced in the flowing direction of fluid; the outer wall face of the reducing pipe section is connected with the end of the turnover section, an annular channel is formed between the outer ring face of the annular pipe section and the outer wall face of the reducing pipe section, the first straight pipe section, the annular pipe section and the reducing pipe section are communicated, and the extending direction of the reducing pipe section is parallel to the extending direction of the annular pipe section; and the second straight pipe section is used for being connected with an outflow pipe. The problem that in the prior art, a conical pipe is prone to being eroded and abraded is solved.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline transportation equipment, in particular to an anti-erosion tapered pipe and a method for determining the size of the anti-erosion tapered pipe. Background Art

[0002] After oil and gas are extracted from underground, they cannot be separated from pipeline transportation. The pipeline transportation system sometimes needs to connect pipelines of different diameters together, and the tapered pipe plays a role in changing the diameter of the pipeline. During the oil and gas development process, some solid particles will enter the pipeline transportation system with the produced medium. In order to improve the transportation efficiency, the movement speed of the fluid medium is often increased, and the impurity particles mixed in it will also move at a faster speed. According to the continuity principle, when the fluid medium and solid particles pass through the tapered pipe, the flow rate will be further increased due to the reduction of the pipe diameter. The faster flow rate will make the solid particles entrained by the fluid faster, the momentum will increase, and the impact force will increase. They will collide at the tapered pipe. After a long period of high pressure and high temperature environment conditions, serious erosion and wear will occur at the tapered pipe, resulting in thinning of the tapered pipe wall thickness and reduced pressure bearing capacity, posing a threat to the life safety of station staff, nearby residents and related personnel, and will also have an adverse impact on the environment.

[0003] That is to say, the conical tube in the prior art has the problem of being easily eroded and worn. Summary of the invention

[0004] The main purpose of the present invention is to provide an erosion-resistant tapered tube and a method for determining the size of the erosion-resistant tapered tube, so as to solve the problem that the tapered tube is easily eroded and worn in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an erosion-resistant conical tube, which includes the following parts connected in sequence along the flow direction of the fluid: a first straight tube section, which is used to be connected to the incoming flow tube; an annular tube section, one end of which is connected to the first straight tube section, and the annular tube section is folded toward the center of the annular tube section away from one end of the first straight tube section to form a folded section, and the diameter of the annular tube section is gradually reduced along the flow direction of the fluid; a reduced diameter tube section, the outer wall surface of the reduced diameter tube section is connected to the end of the folded section, and an annular channel is formed between the outer annular surface of the annular tube section and the outer wall surface of the reduced diameter tube section, and the first straight tube section, the annular tube section and the reduced diameter tube section are connected, and the extension direction of the reduced diameter tube section is parallel to the extension direction of the annular tube section; and a second straight tube section, which is used to be connected to the outflow tube.

[0006] Furthermore, the folded section is in the shape of a circular arc, and twice the radius of curvature of the circular arc is equal to the channel width W of the annular channel.

[0007] Furthermore, the reduced diameter pipe section with the folded section as the boundary includes a first section and a second section, the first section is located on the outside of the annular pipe section, the second section is located on the inside of the annular pipe section and forms an annular channel with the annular pipe, and the total length l2 of the first section and the second section and the length l3 of the second section satisfy: l2=1.5l3.

[0008] Furthermore, an angle α between the annular pipe section and the extension direction of the first straight pipe section, and an angle β between the reduced diameter pipe section and the extension direction of the second straight pipe section satisfy: α=β.

[0009] Furthermore, an angle α between the annular pipe section and the extension direction of the first straight pipe section is greater than or equal to 5° and less than or equal to 10°.

[0010] Furthermore, the erosion-resistant tapered pipe further comprises at least one flange, and the first straight pipe section is connected to the incoming flow pipe via the flange; and / or the second straight pipe section is connected to the outgoing flow pipe via the flange.

[0011] Furthermore, the first straight pipe section is fixed to the annular pipe section by welding; and / or the reduced diameter pipe section is fixed to the second straight pipe section by welding.

[0012] According to another aspect of the present invention, a method for determining the size of an anti-erosion conical tube is provided, and the size determination method is used to determine the size of the above-mentioned anti-erosion conical tube. The method for determining the size of the anti-erosion conical tube includes: step S10: establishing an initial model of the conical tube; step S20: measuring the erosion rate of the conical tube and recording the erosion rate; step S30: determining the adjustment range of the angle α between the annular tube section of the conical tube and the extension direction of the first straight tube section of the conical tube; step S40: adjusting the size of the angle α to form a test model, and recording the size data of the test model; step S50: repeating steps S20 to S40 until the size data and erosion rate of all test models are recorded; step S60: determining the size data of the test model with the smallest erosion rate as the size of the conical tube.

[0013] Furthermore, in step S10, it includes: determining the initial size of the tapered tube; determining the flow parameters of the fluid; determining the boundary conditions; and establishing an initial model of the tapered tube according to the initial size, the flow parameters and the boundary conditions.

[0014] Furthermore, the process of determining the initial size of the tapered tube includes: determining the diameter D of the first straight tube section of the tapered tube; determining the diameter d of the second straight tube section of the tapered tube, wherein the diameter d is smaller than the diameter D; determining the total length l2 of the first section and the second section of the reduced diameter tube section of the tapered tube; determining the length l3 of the second section of the reduced diameter tube section of the tapered tube; determining the length l1 of the outer annular surface of the annular tube section; determining the angle α between the outer annular surface and the extension direction of the outer wall surface of the first straight tube section; determining the angle β between the outer wall surface of the reduced diameter tube section and the extension direction of the outer wall surface of the second straight tube section; determining the channel width W of the annular channel of the tapered tube; and determining the radius of curvature of the circular arc arch of the annular tube section.

[0015] Furthermore, the process of determining the flow parameters of the fluid includes: determining the fluid density of the fluid; determining the particle density of the fluid; determining the velocity of the fluid; determining the particle diameter of the fluid; and determining the mass flow rate of the fluid.

[0016] Furthermore, the process of determining the boundary conditions includes: determining the inlet velocity of the fluid at the tapered tube.

[0017] Further, in step S30, the adjustment range of the angle α is greater than or equal to 5° and less than or equal to 10°, and the adjustment interval of the angle α is 1°.

[0018] By applying the technical solution of the present invention, the erosion-resistant conical pipe includes a first straight pipe section, an annular pipe section, a reduced diameter pipe section and a second straight pipe section which are connected in sequence along the flow direction of the fluid, wherein the first straight pipe section is used to be connected to the incoming flow pipe; one end of the annular pipe section is connected to the first straight pipe section, and the annular pipe section is folded toward the center of the annular pipe section away from one end of the first straight pipe section to form a folded section, and the diameter of the annular pipe section is gradually reduced along the flow direction of the fluid; the outer wall surface of the reduced diameter pipe section is connected to the end of the folded section, and an annular channel is formed between the outer annular surface of the annular pipe section and the outer wall surface of the reduced diameter pipe section, and the first straight pipe section, the annular pipe section and the reduced diameter pipe section are connected, and the extension direction of the reduced diameter pipe section is parallel to the extension direction of the annular pipe section; the second straight pipe section is used to be connected to the outflow pipe.

[0019] By setting an annular pipe section and a reduced diameter pipe section in parallel with the extending directions, and utilizing the folded section to form an annular channel between the outer annular surface of the annular pipe section and the outer wall surface of the reduced diameter pipe section, the fluid can be diverted so that part of the fluid enters the annular channel. Since the end of the annular pipe section away from the first straight pipe section is folded toward the center of the annular pipe section to form a folded section, that is, the end of the annular pipe section away from the first straight pipe section is closed, which changes the flow state of the fluid. The fluid hardly flows at the folded section, which buffers the impact of solid particles on the conical pipe, reduces the number of impacts of solid particles carried by the fluid on the conical pipe, and slows down the erosion rate of the conical pipe. In addition, since the annular pipe section is connected to the first straight pipe section, and the outer wall surface of the reduced diameter pipe section is connected to the end of the folded section, compared with directly connecting the reduced diameter pipe section to the first straight pipe section, the present solution utilizes the width of the annular channel to relatively reduce the inclination degree of the reduced diameter pipe section and the annular pipe section, that is, the taper of the tapered tube, thereby effectively reducing the direct collision of solid particles with the tapered tube. Therefore, the tapered tube of the present application has the effect of not being easily eroded and worn. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A cross-sectional view of a tapered tube according to Embodiment 1 of the present invention is shown;

[0022] Figure 2 Shows Figure 1 A three-dimensional schematic diagram of an angle of the tapered tube in FIG.

[0023] Figure 3 Shows Figure 1 A side view of the tapered tube in FIG.

[0024] Figure 4 Shows Figure 1 A flow chart of a method for determining the size of a tapered tube for erosion protection;

[0025] Figure 5 Shows Figure 1 Erosion rate cloud diagram of the tapered tube in;

[0026] Figure 6 The figure shows an erosion rate contour diagram of a conical tube in the prior art.

[0027] The above drawings include the following reference numerals:

[0028] 10. First straight pipe section; 20. Annular pipe section; 21. Folded section; 30. Reduced diameter pipe section; 31. First section; 32. Second section; 40. Second straight pipe section; 50. Annular channel; 60. Flange. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0031] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0032] In order to solve the problem in the prior art that the tapered tube is easily eroded and worn, the present invention provides an erosion-resistant tapered tube and a method for determining the size of the erosion-resistant tapered tube.

[0033] In the present application, the fluid passes through the inflow pipe, the conical pipe and the outflow pipe in sequence during the flow process. Since the diameters of the inflow pipe and the outflow pipe are different, a conical pipe with a certain taper is required for connection. However, when the fluid flows at a faster speed, the solid particles carried will also move at a faster speed, which has a greater impact on the conical pipe. The conical pipe for anti-erosion of the present application reduces the flow rate of part of the fluid by diverting and reducing the taper, reducing the erosion and wear on the outer wall of the conical pipe. It can also concentrate the erosion of the conical pipe from the outer wall to the second section 32 of the reduced diameter pipe section 30 located inside the conical pipe, further alleviating the direct impact of solid particles on the outer wall of the conical pipe. The anti-erosion conical pipe of the present application also has the characteristics of simple structure, low manufacturing cost and easy replacement.

[0034] like Figures 1 to 5As shown, the erosion-resistant conical pipe includes a first straight pipe section 10, an annular pipe section 20, a reduced diameter pipe section 30 and a second straight pipe section 40 which are connected in sequence along the flow direction of the fluid. The first straight pipe section 10 is used to connect with the incoming flow pipe; one end of the annular pipe section 20 is connected with the first straight pipe section 10, and the end of the annular pipe section 20 away from the first straight pipe section 10 is folded toward the center of the annular pipe section 20 to form a folded section 21, and the diameter of the annular pipe section 20 is gradually reduced along the flow direction of the fluid; the outer wall surface of the reduced diameter pipe section 30 is connected with the end of the folded section 21, and an annular channel 50 is formed between the outer annular surface of the annular pipe section 20 and the outer wall surface of the reduced diameter pipe section 30, and the first straight pipe section 10, the annular pipe section 20 are connected with the reduced diameter pipe section 30, and the extension direction of the reduced diameter pipe section 30 is parallel to the extension direction of the annular pipe section 20; the second straight pipe section 40 is used to connect with the outflow pipe.

[0035] By providing an annular pipe section 20 and a reduced diameter pipe section 30 with parallel extension directions, and utilizing the folded section 21 to form an annular channel 50 between the outer annular surface of the annular pipe section 20 and the outer wall surface of the reduced diameter pipe section 30, the fluid can be diverted so that part of the fluid enters the annular channel 50. Since the end of the annular pipe section 20 away from the first straight pipe section 10 is folded toward the center of the annular pipe section 20 to form the folded section 21, that is, the end of the annular pipe section 20 away from the first straight pipe section 10 is closed, which changes the flow state of the fluid. The fluid hardly flows at the folded section 21, which buffers the impact of solid particles on the conical tube, reduces the number of impacts of solid particles carried by the fluid on the conical tube, and slows down the erosion rate of the conical tube. In addition, since the annular pipe section 20 is connected to the first straight pipe section 10, and the outer wall surface of the reduced diameter pipe section 30 is connected to the end of the folded section 21, compared with directly connecting the reduced diameter pipe section 30 to the first straight pipe section 10, the present solution utilizes the width of the annular channel 50 to relatively reduce the inclination degree of the reduced diameter pipe section 30 and the annular pipe section 20, that is, the taper of the tapered tube, thereby effectively reducing the direct collision of solid particles with the tapered tube. Therefore, the tapered tube of the present application has the effect of not being easily eroded and worn.

[0036] like Figure 1 As shown, the folded section 21 is in an arc shape, and twice the radius of curvature of the arc shape is equal to the channel width W of the annular channel 50. That is to say, in the cross-section along the central axis of the tapered tube, one side of the arc shape is a semicircular surface, and the outer annular surface of the annular tube section 20 extending parallel to the diameter of the semicircular surface and the outer wall surface of the reduced diameter tube section 30 form the annular channel 50. This arrangement is convenient for slowing down the speed of the fluid in the annular channel 50 and is also convenient for the molding of the annular tube section 20.

[0037] like Figure 1As shown, the reduced diameter pipe section 30 with the folded section 21 as the boundary includes a first section 31 and a second section 32, the first section 31 is located outside the annular pipe section 20, the second section 32 is located inside the annular pipe section 20 and forms an annular channel 50 with the annular pipe section 20, and the total length l2 of the first section 31 and the second section 32 and the length l3 of the second section 32 satisfy: l2 = 1.5l3. In this arrangement, the second section 32 of the reduced diameter pipe section 30 is used to guide the flow, and the second section 32 is in the flow-facing position, so that the position with the largest fluid erosion is the second section 32, thereby reducing the erosion of the fluid on the outer wall of the tapered pipe, and avoiding the situation where the tapered pipe is seriously worn or even leaks.

[0038] like Figure 1 As shown, the angle α between the annular pipe section 20 and the extension direction of the first straight pipe section 10, and the angle β between the extension direction of the reduced diameter pipe section 30 and the second straight pipe section 40 satisfy: α=β. That is, the extension direction of the first straight pipe section 10 is the same as the extension direction of the second straight pipe section 40, and the extension direction of the reduced diameter pipe section 30 is parallel to the extension direction of the annular pipe section 20.

[0039] Specifically, the angle α between the annular pipe section 20 and the extension direction of the first straight pipe section 10 is greater than or equal to 5° and less than or equal to 10°. This arrangement allows the taper of the tapered pipe to be within a smaller range, which is beneficial to reducing the direct collision of solid particles with the outer wall of the tapered pipe, thereby extending the service life of the tapered pipe.

[0040] like Figures 1 to 3 As shown, the erosion-resistant conical tube further comprises at least one flange 60, and optionally, the first straight tube section 10 is connected to the incoming flow tube via the flange 60; optionally, the second straight tube section 40 is connected to the outgoing flow tube via the flange 60. The stability of the connection between the two ends of the conical tube and the incoming flow tube and the outgoing flow tube can be ensured, and the conical tube can be easily replaced or solid impurities in the inner cavity of the conical tube can be removed.

[0041] Optionally, the first straight pipe section 10 is welded to the annular pipe section 20; and optionally, the reduced diameter pipe section 30 is welded to the second straight pipe section 40. The welding fixation method can ensure the stability of the connection and avoid leakage problems at the connection.

[0042] like Figure 4As shown, the present invention also provides a method for determining the size of an anti-erosion conical tube, which is used to determine the size of the anti-erosion conical tube of the present application. The method for determining the size of an anti-erosion conical tube includes: step S10: establishing an initial model of the conical tube; step S20: measuring the erosion rate on the second section 32 of the reduced diameter tube section 30 of the conical tube, and recording the erosion rate; step S30: determining the adjustment range of the angle α between the annular tube section 20 of the conical tube and the extension direction of the first straight tube section 10 of the conical tube; step S40: adjusting the size of the angle α to form a test model, and recording the size data of the test model; step S50: repeating steps S20 to S40 until the size data and erosion rate of all test models are recorded; step S60: determining the size data of the test model with the smallest erosion rate as the size of the conical tube.

[0043] By establishing an initial model of the tapered tube through step S10 and measuring the erosion rate on the second section 32 of the reduced diameter tube section 30, the erosion degree of the entire tapered tube can be simulated, and then through steps S30 and S40, the angle α, that is, the taper of the tapered tube is adjusted at certain intervals, and through step S50, the erosion rate on the second section 32 of the reduced diameter tube section 30 is recorded in time each time the angle α is adjusted. After all the values ​​of α are recorded within the adjustment range of the angle α, the size of the test model with the smallest erosion rate is selected as the final size of the tapered tube in step S60.

[0044] Specifically, in step S10, it includes: determining the initial size of the tapered tube; determining the flow parameters of the fluid; determining the boundary conditions; and establishing the initial model of the tapered tube according to the initial size, the flow parameters and the boundary conditions.

[0045] The following is a specific description. In the process of determining the initial size of the tapered tube, the following steps are included: determining the diameter D of the first straight tube section 10 of the tapered tube; determining the diameter d of the second straight tube section 40 of the tapered tube, and the diameter d is smaller than the diameter D; determining the total length l2 of the first section and the second section of the tapered tube section 30; determining the length l3 of the second section 32 of the tapered tube section 30; determining the length l1 of the outer annular surface of the annular tube section 20; determining the angle α between the outer annular surface and the extension direction of the outer wall surface of the first straight tube section 10; determining the angle β between the outer wall surface of the tapered tube section 30 and the extension direction of the outer wall surface of the second straight tube section 40; determining the channel width W of the annular channel of the tapered tube; and determining the curvature radius r of the circular arc of the annular tube section 20. Among them, l2=1.5l3, α=β, and W=2r. It should be noted that D and d are respectively equal to the inner diameters of the incoming flow tube and the outgoing flow tube.

[0046] Specifically, in the process of determining the flow parameters of the fluid, the following are included: the fluid density of the fluid; the particle density of the fluid; the velocity of the fluid; the particle diameter of the fluid; and the mass flow rate of the fluid. This is to simulate the application environment of the tapered tube, so as to more accurately grasp the life of the tapered tube in the application environment.

[0047] Specifically, the process of determining the boundary conditions includes determining the inlet velocity of the fluid at the tapered tube, wherein the inlet velocity of the fluid at the tapered tube is equal to the velocity of the fluid.

[0048] Embodiment 1

[0049] like Figures 1 to 6 As shown, the initial dimensions of the tapered tube in this embodiment are: D is 100 mm, d is 60 mm, l1=l2=1.5l3=56 mm, α=β=5°, and the lengths of the first straight tube section 10 and the second straight tube section 40 along the central axis of the tapered tube are both L.

[0050] Fluid flow parameters: Fluid density 890kg / m 3 , particle density is 1500kg / m 3 , speed V is 10m / s, particle diameter is 0.2mm, and mass flow rate is 0.01kg / s;

[0051] The boundary conditions are set as follows: the inlet is the velocity inlet, the inlet velocity is equal to the velocity of the fluid, the outlet is the free outflow, and the other boundaries are set as the wall.

[0052] Specifically, the adjustment range of the angle α is greater than or equal to 5° and less than or equal to 10°, and the adjustment interval of the angle α is 1°. In this range, multiple groups of test model size data and erosion rates can be obtained, so that the group with the smallest erosion rate is selected as the size of the final tapered tube in this application scenario. After simulation, α=β=8° and r=5mm are taken.

[0053] The measurement results show that the maximum erosion rate of the tapered tube in this embodiment is 6.38×10 -8 kg / (m 2 ·s).

[0054] Under the same environmental conditions, the specific parameters of the conical tube in the prior art are set as follows: D is 100 mm, d is 60 mm, and the length of the entire conical tube along the fluid flow direction is 77 mm. The erosion rate of the conical tube in the prior art is 5.74×10 -8 kg / (m 2 ·s), although the maximum erosion rate of the tapered tube in this embodiment is greater than that of the ordinary tapered tube, Figure 5 and Figure 6It can be seen that the maximum erosion rate of this embodiment mainly occurs in the second section 32 of the reduced diameter section 30 of the tapered tube, which is a non-important part. The difference is also within an acceptable range, and the erosion rate on the entire tapered tube is relatively high. Figure 6 The erosion rate on the prior art tapered tube is shown to be much lower.

[0055] In summary, this embodiment can significantly reduce the erosion rate on the tapered tube, thereby achieving the purpose of extending the service life of the tapered tube.

[0056] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0057] 1. The end of the annular pipe section 20 away from the first straight pipe section 10 is closed, which changes the flow state of the fluid. The fluid hardly flows at the folded section 21, which buffers the impact of solid particles on the tapered pipe, reduces the number of impacts of solid particles carried by the fluid on the tapered pipe, and slows down the erosion rate of the tapered pipe.

[0058] 2. The width of the annular channel 50 is used to relatively reduce the inclination of the reduced diameter pipe section 30 and the annular pipe section 20, that is, the taper of the tapered pipe, thereby effectively reducing the direct collision of solid particles on the tapered pipe. Therefore, the tapered pipe of the present application has the effect of being less susceptible to erosion and wear.

[0059] 3. The second section 32 of the reduced diameter pipe section 30 is used for drainage. Meanwhile, the second section 32 is located in the flow-facing position, so that the position with the greatest fluid erosion is the second section 32, thereby reducing the erosion of the fluid on the outer wall of the tapered tube and avoiding severe wear or even leakage of the tapered tube.

[0060] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0061] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-erosion tapered tube, characterized in that: The tapered tube includes: A first straight pipe section (10), the first straight pipe section (10) being used to be connected to an incoming flow pipe; an annular pipe section (20), one end of the annular pipe section (20) being connected to the first straight pipe section (10), one end of the annular pipe section (20) away from the first straight pipe section (10) being folded toward the center of the annular pipe section (20) to form a folded section (21), and the diameter of the annular pipe section (20) being gradually reduced along the flow direction of the fluid; a reduced diameter pipe section (30), wherein the outer wall surface of the reduced diameter pipe section (30) is connected to the end of the folded section (21), and an annular channel (50) is formed between the outer annular surface of the annular pipe section (20) and the outer wall surface of the reduced diameter pipe section (30), and the first straight pipe section (10), the annular pipe section (20) and the reduced diameter pipe section (30) are connected, and the extension direction of the reduced diameter pipe section (30) is parallel to the extension direction of the annular pipe section (20); A second straight pipe section (40), wherein the second straight pipe section (40) is used to be connected to the outlet pipe.

2. The erosion-resistant tapered tube according to claim 1, characterized in that: The folded section (21) is in the shape of a circular arc, and twice the radius of curvature of the circular arc is equal to the channel width W of the annular channel (50).

3. The erosion-resistant tapered tube according to claim 1, characterized in that: The reduced diameter pipe section (30) comprises a first section (31) and a second section (32) with the folded section (21) as a boundary, the first section (31) being located on the outside of the annular pipe section (20), the second section (32) being located on the inside of the annular pipe section (20) and forming the annular channel (50) with the annular pipe, and the total length l2 of the first section (31) and the second section (32) and the length l3 of the second section (32) satisfying: l2=1.5l3.

4. The erosion-resistant tapered tube according to claim 1, characterized in that: The angle α between the annular pipe section (20) and the extension direction of the first straight pipe section (10), and the angle β between the reduced diameter pipe section (30) and the extension direction of the second straight pipe section (40) satisfy: α=β.

5. The erosion-resistant tapered tube according to claim 4, characterized in that: An included angle α between the extending direction of the annular pipe section (20) and the first straight pipe section (10) is greater than or equal to 5° and less than or equal to 10°.

6. The erosion-resistant tapered tube according to any one of claims 1 to 5, characterized in that: The erosion-resistant conical tube further comprises at least one flange (60), The first straight pipe section (10) is connected to the incoming flow pipe via the flange (60); and / or The second straight pipe section (40) is connected to the outlet pipe via the flange (60).

7. The erosion-resistant tapered tube according to any one of claims 1 to 5, characterized in that: The first straight pipe section (10) and the annular pipe section (20) are fixed by welding; and / or The reduced diameter pipe section (30) and the second straight pipe section (40) are fixed by welding.

8. A method for determining the size of a tapered tube for erosion prevention, characterized in that: The size determination method is used to determine the size of the anti-erosion tapered tube according to any one of claims 1 to 7, and the size determination method for the anti-erosion tapered tube comprises: Step S10: establishing an initial model of the tapered tube; Step S20: measuring the erosion rate of the tapered tube and recording the erosion rate; Step S30: determining an adjustment range of an angle α between the annular tube section (20) of the tapered tube and the extension direction of the first straight tube section (10) of the tapered tube; Step S40: adjusting the size of the angle α to form a test model, and recording the dimension data of the test model; Step S50: repeating steps S20 to S40 until the dimension data and the erosion rate of all the test models are recorded; Step S60: Determine the dimension data of the test model with the minimum erosion rate as the dimension of the tapered tube.

9. The method for determining the size of a tapered tube for erosion prevention according to claim 8, characterized in that: In the step S10, it includes: Determining the initial dimensions of the tapered tube; Determine the flow parameters of the fluid; Determine boundary conditions; An initial model of the tapered tube is established according to the initial size, the flow parameters and the boundary conditions.

10. The method for determining the size of a tapered tube for erosion prevention according to claim 9, characterized in that: The process of determining the initial size of the tapered tube includes: Determining the diameter D of the first straight pipe section (10); Determining a diameter d of the second straight pipe section (40) of the tapered pipe, wherein the diameter d is smaller than the diameter D; Determining the total length l2 of the first section (31) and the second section (32) of the reduced diameter pipe section (30) of the tapered pipe; Determining the length l3 of the second segment (32); Determining the length l1 of the outer annular surface of the annular pipe section (20); Determining an angle α between the outer annular surface and the extension direction of the outer wall surface of the first straight pipe section (10); Determining an angle β between the outer wall surface of the reduced diameter pipe section (30) and the extension direction of the outer wall surface of the second straight pipe section (40); Determining a channel width W of the annular channel (50) of the tapered tube; The curvature radius of the circular arc arch of the annular pipe section (20) is determined.

11. The method for determining the size of a tapered tube for erosion prevention according to claim 9, characterized in that: The process of determining the flow parameters of the fluid includes: a fluid density of the fluid; determining a particle density of the fluid; determining a velocity of the fluid; determining a particle diameter of the fluid; The mass flow rate of the fluid is determined.

12. The method for determining the size of a tapered tube for erosion prevention according to claim 9, characterized in that: The process of determining the boundary conditions includes: determining the inlet velocity of the fluid at the tapered tube.

13. The method for determining the size of a tapered tube for erosion prevention according to claim 8, characterized in that: In the step S30, the adjustment range of the angle α is greater than or equal to 5° and less than or equal to 10°, and the adjustment interval of the angle α is 1°.

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