A double U-shaped pipeline applied to a fluid shock environment

Abstract

A double U type pipeline applied to jet flow impact environment relates to a double U type pipeline. The present application is to solve the problem of erosion and cavitation damage of high-speed jet flow to the elbow of the U type pipeline in the prior art. The present application comprises a U type pipe and a second semicircular elbow. The U type pipe comprises a first straight pipe, a first semicircular elbow and a second straight pipe connected in sequence, and the curvature radius of the first semicircular elbow is R1. The second semicircular elbow is arranged in parallel with the first semicircular elbow, the spacing between the second semicircular elbow and the first semicircular elbow is L, and L=R1. The inlet and outlet of the second semicircular elbow are respectively connected with the outer circumferential surface of the first straight pipe and the second straight pipe through welding at the penetrating position. Further, the high pressure area and the high speed area in the turning process of the jet flow are separated by the cooperation of the two semicircular elbows, and the speed of the fluid is reduced as a whole, thereby reducing the erosion effect of particles on the pipe wall. The present application belongs to the technical field of elbow protection.

Description

TECHNICAL FIELD

[0001] The application relates to a double-U type pipeline, in particular to a double-U type pipeline applied to a jet impact environment, and belongs to the technical field of bend protection. BACKGROUND

[0002] The pipeline is a main component for realizing liquid conveying, completing heat exchange or realizing energy transmission; when liquid flows through the bend of the U type pipeline, the size and direction of the flow rate change, and eddies appear in the flow, and the fluid collides and impacts each other, which is a main form of loss of pipeline conveying efficiency; on the other hand, the liquid forms obvious high-pressure and low-pressure zones on the outer arc side and the inner arc side of the bend. The high-pressure zone is subjected to fluid erosion, and especially when the fluid contains impurity particles, the erosion is more likely to occur; the low-pressure zone is prone to bubble separation, and the rupture of the bubbles causes vibration and cavitation. Especially for the U type pipeline applied to a high-speed jet working condition, the erosion and cavitation have a more obvious destructive effect on the bend, thereby reducing the service life of the U type pipeline.

[0003] To sum up, how to solve the above technical problems by providing a new U type pipeline has become a problem to be solved by the technical personnel in the field. SUMMARY

[0004] The application provides a double-U type pipeline applied to a jet impact environment.

[0005] The technical scheme of the application is as follows: a double-U type pipeline applied to a jet impact environment, comprising a U type pipeline and a second semicircular bend.

[0006] The U type pipeline comprises a first straight pipe, a first semicircular bend and a second straight pipe connected in sequence, the first straight pipe is a liquid inlet pipe, the second straight pipe is a liquid outlet pipe, and the curvature radius of the first semicircular bend is R1.

[0007] The second semicircular bend is arranged in parallel with the first semicircular bend, the distance between the second semicircular bend and the first semicircular bend is L, and L=R1. The inlet and the outlet of the second semicircular bend are respectively connected with the outer circumferential surfaces of the first straight pipe and the second straight pipe through welding at the connection positions.

[0008] Further, the curvature radius of the second semicircular bend is R2, and R2=R1.

[0009] Further, the inner diameters of the second semicircular bend, the first semicircular bend, the second straight pipe and the first straight pipe are r.

[0010] Further, a cutting surface is cut at the inlet of the second semicircular bend, the cutting surface is parallel to the axis of the first straight pipe, and the distance between the cutting surface and the axis of the first straight pipe is d, and d=0-0.2r.

[0011] Compared with the prior art, the present application has the following effects:

[0012] 1、The present application has simple structure, is suitable for high-speed jet flow working condition, separates the high-pressure area and high-speed area in the jet flow turning process through the cooperation of the two semicircular elbows, and reduces the speed of the fluid as a whole, thereby reducing the particle erosion effect on the pipe wall. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is the axonometric view of the present application;

[0014] Figure 2 is the front view of the present application;

[0015] Figure 3 is the pressure distribution nephogram of high-speed jet flow impacting the common U-shaped pipeline, and the transition from blue to red in the nephogram indicates that the pressure of the high-speed jet flow on the pipe wall is getting larger and larger;

[0016] Figure 4 is the pressure distribution nephogram of high-speed jet flow impacting the present application, and the transition from blue to red in the nephogram indicates that the pressure of the high-speed jet flow on the pipe wall is getting larger and larger, and the distance d between the cutting surface and the axis of the first straight pipe 1 is 0;

[0017] Figure 5 is the flow velocity diagram of high-speed jet flow in the common U-shaped pipeline, and the transition from blue to red on the line indicates that the flow velocity of the high-speed jet flow is getting larger and larger;

[0018] Figure 6 is the flow velocity diagram of high-speed jet flow in the present application, and the transition from blue to red on the line indicates that the flow velocity of the high-speed jet flow is getting larger and larger, and the distance d between the cutting surface and the axis of the first straight pipe 1 is 0;

[0019] Figure 7 is the particle impact diagram of particle erosion of the common U-shaped pipeline in high-speed jet flow, and the transition from blue to red on the particle indicates that the particle erosion effect of the particle on the pipe wall is getting stronger and stronger;

[0020] Figure 8 is the particle impact diagram of particle erosion of the present application in high-speed jet flow, and the transition from blue to red on the particle indicates that the particle erosion effect of the particle on the pipe wall is getting stronger and stronger, and the distance d between the cutting surface and the axis of the first straight pipe 1 is 0;

[0021] Figure 9 is the corrosion rate diagram of particle erosion of the common U-shaped pipeline in high-speed jet flow, and the transition from blue to red in the diagram indicates that the corrosion rate is getting larger and larger;

[0022] Figure 10is the erosion rate diagram of the particle erosion in the high-speed jet after the application, the transition from blue to red in the diagram indicates that the erosion rate is getting larger, and the distance d between the cutting surface and the axis of the first straight pipe 1 is 0;

[0023] Figure 11 is the erosion rate diagram of the particle erosion in the high-speed jet after the application, the transition from blue to red in the diagram indicates that the erosion rate is getting larger, and the distance d between the cutting surface and the axis of the first straight pipe 1 is 0.2r.

[0024] In the figure: 1, the first straight pipe; 2, the second straight pipe; 3, the first semicircular elbow; 4, the second semicircular elbow. DETAILED DESCRIPTION

[0025] In order to make the application purpose, features and advantages of the application more obvious and easy to understand, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application.

[0026] Specific embodiment one: in combination with Figures 1 to 2 It is explained that the embodiment, a double U-shaped pipeline applied in a jet impact environment in the embodiment includes a U-shaped pipe and a second semicircular elbow 4, and the materials of the U-shaped pipe and the second semicircular elbow 4 are medium carbon steel.

[0027] The U-shaped pipe includes a first straight pipe 1, a first semicircular elbow 3 and a second straight pipe 2 connected in sequence, the first straight pipe 1 is a liquid inlet pipe, the second straight pipe 2 is a liquid outlet pipe, and the curvature radius of the first semicircular elbow 3 is R1.

[0028] The second semicircular elbow 4 is arranged in parallel with the first semicircular elbow 3, the curvature radius of the second semicircular elbow 4 is R2, and R2=R1. The distance between the second semicircular elbow 4 and the first semicircular elbow 3 is L, and L=R1. The inlet and outlet of the second semicircular elbow 4 respectively penetrate the outer circumferential surface of the first straight pipe 1 and the second straight pipe 2, and are connected by welding at the penetration positions.

[0029] Specific embodiment two: in combination with Figures 1 to 2 It is explained that the embodiment, the inner diameters of the second semicircular elbow 4, the first semicircular elbow 3, the second straight pipe 2 and the first straight pipe 1 in the embodiment are all r.

[0030] Further, a cutting surface is cut at the inlet of the second semicircular elbow 4, the cutting surface is parallel to the axis of the first straight pipe 1, and the distance between the cutting surface and the axis of the first straight pipe 1 is d, d=0~0.2r.

[0031] The fluid in the first straight pipe 1 is divided into the second semicircular bend pipe 4 when flowing through the cutting surface. When d increases, the cutting surface of the second semicircular bend pipe 4 is also increased. When the jet flow contains impurity particles, the distance d between the cutting surface of the second semicircular bend pipe 4 and the axis of the first straight pipe 1 can be adjusted to reduce the influence of the impurity particles on the erosion of the present application.

[0032] Other components and connection relationships are the same as in the specific embodiment.

[0033] Working principle

[0034] Combination Figures 1 to 11 The working principle of the present application is described as follows:

[0035] Because the flow process of the jet flow at the bend pipe is complex, it is difficult to directly obtain the mechanism of the working principle. Here, COMSOL Multiphysics simulation software is used to analyze the flow of the ordinary U-shaped pipe and the present application, and then the working principle of the present application is described.

[0036] The COMSOL Multiphysics software has a DNV particle erosion model (a model proposed by Det-Norske-Vertitas Company for calculating the erosion and corrosion rate of the pipe made of carbon steel material), the DNV model is used to analyze the main erosion position of the wall surface and the corrosion rate of the particle (referred to as particle in the software, simulating the impurity particles in the jet flow), the pipe diameter of the ordinary bend pipe and the present application is kept the same in the software, and the jet flow velocity at the inlet of the two is set to 8 m / s, the size and characteristics of the particle are the same, and the calculation results are analyzed as follows:

[0037] As shown in Figure 3 , the pressure gradient of the ordinary U-shaped pipe is large, the outer arc side of the bend pipe is a high-pressure area, the inner arc side of the bend pipe is a low-pressure area, and a negative pressure is formed. In the process of jet flow, the high-pressure area will form stress on the pipe wall material; if the jet flow contains bubbles, cavitation will be formed in the low-pressure area.

[0038] As shown in Figure 4 , the pressure gradient in the present application is relatively uniform, and the high-pressure area is mainly distributed in the first semicircular bend pipe 3. Because the jet flow in the first straight pipe 1 is divided into the first semicircular bend pipe 3 and the second semicircular bend pipe 4 at the cutting surface, the fluid in the first semicircular bend pipe 3 and the second semicircular bend pipe 4 will be mixed at the communication between the second semicircular bend pipe 4 and the second straight pipe 2. The pressure of the fluid after mixing increases, and then the pressure borne by the first semicircular bend pipe 3 increases as a whole, which is slightly higher than that of the ordinary U-shaped pipe. Although there is a low-pressure area on the inner arc side of the second semicircular bend pipe 4, no negative pressure is formed to avoid cavitation.

[0039] As shown in Figure 5As shown, the jet velocity at the entrance of the common U-shaped pipeline is 8 m / s, but the jet velocity at the elbow exceeds 9 m / s; as shown, Figure 6 As shown, the jet velocity in the first semicircular elbow 3 and the second semicircular elbow 4 in the present application is less than 7 m / s, especially in the first semicircular elbow 3 at the high pressure, the flow rate is less than 5 m / s; therefore, in the high pressure area, the flow rate is low, and the erosion rate can be reduced.

[0040] As shown, Figure 7 As shown, in the common U-shaped pipeline, when the jet velocity is 8 m / s, the particles impact the wall surface on the outer arc side of the elbow, and the maximum speed can reach 9 m / s; and as shown, Figure 9 As shown, the corrosion position is also concentrated on the wall surface on the outer arc side of the elbow, and the corrosion rate is greater than 20×10 -11 kg / (m 2 ·s).

[0041] As shown, Figure 8 As shown, in the present application, the particles are mainly distributed in the second semicircular elbow 4, and the speed is less than 7 m / s; as shown, Figure 10 As shown, the corrosion position is also concentrated on the wall surface on the outer arc side of the second semicircular elbow 4, and the corrosion rate is less than 9×10 -11 kg / (m 2 ·s), in order to further reduce the corrosion rate of the second semicircular elbow 4, the distance d between the cutting surface of the second semicircular elbow 4 and the axis of the first straight pipe 1 is adjusted, it should be noted that when the distance d is increased, the flow rate of the jet entering the first semicircular elbow 3 will increase, thereby the corrosion of the first semicircular elbow 3 will increase, therefore, the optimal solution of the distance d is d=0.2r, as shown, Figure 11 As shown, when d=0.2r, the corrosion rate of the second semicircular elbow 4 will be 5×10 -11 kg / (m 2 ·s).

[0042] The present application has been disclosed in the above-mentioned preferred embodiments, however, it is not intended to limit the present application, any person skilled in the art, without departing from the technical solution of the present application, according to the technical essence of the present application, any simple modification, equivalent change and modification of the above-mentioned embodiments, still belongs to the technical solution range of the present application.

Claims

1. A double U-shaped pipe for use in a jet impact environment, comprising a U-shaped pipe, wherein the U-shaped pipe comprises a first straight pipe (1), a first semicircular curved pipe (3), and a second straight pipe (2) connected in sequence, wherein the first straight pipe (1) is a liquid inlet pipe, the second straight pipe (2) is a liquid outlet pipe, and the curvature radius of the first semicircular curved pipe (3) is R1; and characterized in that: The second half-circle elbow pipe (4) is arranged in parallel with the first half-circle elbow pipe (3), the interval between the second half-circle elbow pipe (4) and the first half-circle elbow pipe (3) is L, and L=R1; the inlet and the outlet of the second half-circle elbow pipe (4) are respectively penetrated with the outer circumferential surface of the first straight pipe (1) and the second straight pipe (2), and the penetrated positions are connected through welding. The curvature radius of the second half-circle elbow pipe (4) is R2, and R2=R1; a cutting surface is cut at the inlet of the second half-circle elbow pipe (4), the cutting surface is parallel with the axis of the first straight pipe (1), and the interval between the cutting surface and the axis of the first straight pipe (1) is d, d=0-0.2r. The material of the U-shaped pipe and the second half-circle elbow pipe (4) is medium carbon steel. ​ 2. The double-U shaped pipeline applied to the fluid impact environment according to claim 1, wherein: ​

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