A pipe flow experimental device for simulating axial erosion corrosion of pipeline inner wall

Abstract

The present invention relates to the field of erosion corrosion devices, and specifically to a pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline. The device is provided with an experimental loop part, a cooling loop part, and a test system. The electrochemical test pipe sections of the experimental loop part are distributed on the upper and lower sides of the weightlessness test pipe section. The samples of the electrochemical test pipe section are circular curved surface samples cut from the pipe to be tested, fixed to the inner wall of the test pipe section by a special sealing insulating clamp, and connected to the test system by a wire; the samples of the weightlessness test pipe section are multiple short tubular samples cut from the pipe to be tested, separated from each other by special insulating washers and fixed inside the test pipe section. The present invention studies the axial erosion corrosion behavior of the inner wall of the pipeline under the conditions of truly simulating the actual pipe flow working conditions, can accurately control the test parameters such as temperature and flow rate, and simulate the initial immersion environment of the pipeline, etc., to realize the online electrochemical monitoring and weightlessness testing of multiple identical or different tubular samples.

Description

Technical Field

[0001] The invention relates to the field of erosion corrosion devices, in particular to a pipe flow type experimental device for simulating axial erosion corrosion of the inner wall of a pipeline. Background Art

[0002] In the prior art, there are three types of erosion corrosion test devices: rotary, jet, and tube flow. Among them: the rotary device is based on the tangential force generated by the relative motion between the sample and the liquid, causing the sample to corrode or wear. However, the linear speed of the stirring wheel used in the rotary device is different from the relative speed between the sample and the solution. The actual relative speed is not easy to accurately control. The sample test surface is often a flat or tubular outer surface, which cannot simulate the actual erosion corrosion of the inner wall of the pipeline. In addition, the processing state and stress state of the flat sample surface are different from those of the tubular sample. The jet test device uses a circulating pump and a nozzle to generate a high-speed flow medium to impact the sample. The structure can accurately control the flow rate of the impact liquid flow and change the scouring angle, but the sample test surface is often flat, and the scouring intensity is greater than the actual situation, which is somewhat different from the actual scouring and corrosion conditions of pumps and pipelines. In addition, the diameter of the nozzle will also change due to the scouring effect; the tube flow device is based on a liquid flow / pipeline static structure, which can better simulate the axial scouring and corrosion behavior of the fluid along the inner wall of the pipeline, which is the same as the actual tube flow working conditions. However, the traditional tube flow device is bulky, has high construction and operation costs, is unstable, has a long experimental cycle, and cannot perform electrochemical tests and weight loss tests on multiple samples at the same time. Summary of the Invention

[0003] The purpose of the present invention is to provide a pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, so as to solve the problems that the existing pipe flow erosion corrosion experimental device cannot perform electrochemical testing and weight loss testing at the same time, the device is bulky and the experimental cost is high, and the rotary and jet devices cannot accurately simulate actual pipe flow working conditions.

[0004] The technical solution of the present invention is:

[0005] A pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, comprising an experimental loop part, a cooling loop part, and a test system. The water outlet of a submersible pump is connected to the inlet end of the experimental loop part via a plastic hose I. Electrochemical test pipe sections of the experimental loop part are distributed on the upper and lower sides of the weightlessness test pipe section. Samples of the electrochemical test pipe sections are connected to the test system via wires. The outlet end of the experimental loop part is immersed below the liquid level of a water reservoir. The water inlet of a horizontal pipe pump of the cooling loop part extends into the bottom of the water reservoir via a stainless steel braided pipe. The water outlet of the horizontal pipe pump is connected to the water inlet of a cooler via a plastic hose II. The water outlet of the cooler is connected to one end of a plastic hose III. The other end of the plastic hose III is immersed below the liquid level of the water reservoir.

[0006] The described pipe flow experimental device for simulating axial erosion corrosion of the inner wall of the pipeline, the experimental loop part is provided with a water reservoir, a submersible pump, a plastic hose I, an electromagnetic flowmeter, an electrochemical test pipe segment I, an electrochemical test pipe segment II, an electrochemical test pipe segment III, an electrochemical test pipe segment IV, and a weightlessness test pipe segment. The submersible pump is arranged at the bottom of the water reservoir, and the water outlet of the submersible pump is connected to one end of the plastic hose I through a stainless steel conical tube, and the other end of the plastic hose I is connected to the inlet end of the experimental loop part; in the upward pipeline of the experimental loop part, the electromagnetic flowmeter, electrochemical test pipe segment IV, electrochemical test pipe segment III, weightlessness test pipe segment, electrochemical test pipe segment II, and electrochemical test pipe segment I are arranged in sequence from bottom to top, the electromagnetic flowmeter is fixed to the pipeline bracket by a lifting device, and the two ends of the electromagnetic flowmeter are connected to the pipeline on the experimental loop through flanges welded with snaps.

[0007] The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of the pipeline is characterized in that a valve II is installed on the pipe section connecting the electromagnetic flowmeter and the plastic hose I, and a vertical bypass is provided on the pipe section, the lower end of the bypass extends to the upper part of the water reservoir, and a valve I is installed on the bypass.

[0008] In the pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, a valve V is installed in the downpipe of the experimental loop portion, and a vertical bypass is provided on the downpipe, the lower port of the bypass is located above the water reservoir, and a valve IV is installed on the bypass; the lower port of the downpipe of the experimental loop portion is the outlet end of the experimental loop portion, and the outlet end of the experimental loop portion is immersed below the liquid level of the water reservoir.

[0009] In the pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, the upward pipeline of the experimental loop part and the downward pipeline of the experimental loop part are parallel to each other, the upper port of the upward pipeline and the upper port of the downward pipeline are connected by a horizontal pipeline, and a horizontal bypass is provided on the horizontal pipeline, one end of the bypass is open, and a valve III is installed on the bypass.

[0010] The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of the pipeline is characterized in that the pipeline in the experimental loop part is fixed by a pipeline bracket, adjacent pipe sections in the experimental loop part are fixed by buckles, adjacent pipe sections in the experimental loop part are waterproofly sealed by rubber sealing rings, and the inner wall of the pipeline in the experimental loop part is rust-proofed.

[0011] The tube flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, the electrochemical test tube section I, the electrochemical test tube section II, the electrochemical test tube section III, and the electrochemical test tube section IV are all five-way structures, and the five-way structure includes: a compression screw, a compression nut, a quick interface, a buckle, a five-way pipe, a counter electrode sample, a working electrode sample, an electrode outer support, an adjustment gasket, an electrode inner support, a wire, a rubber sealing ring I, a rubber sealing ring II, a rubber sealing ring III, a threaded pressure cap, a reference electrode, a rubber sealing ring IV, and a reference electrode support. The specific structure is as follows:

[0012] A pair of electrode holders are symmetrically inserted into the inner cavities of two opposite passages of the five-way pipe. The counter electrode sample and the working electrode sample are respectively arranged in the inner cavity of one electrode holder. The counter electrode sample and the working electrode sample are arranged opposite to each other. An electrode inner holder is inserted into the inner cavity of each electrode holder. The backs of the counter electrode sample and the working electrode sample are respectively connected to a wire. Each wire extends through the central hole of the electrode inner holder, and the extended end of the wire is connected to the test system. A rubber sealing ring II is provided between the contact surface of the electrode outer holder and the outer end surface of the pair of opposite passages of the five-way pipe, and a rubber sealing ring I is provided between the contact surface of the electrode inner holder and the outer end surface of the electrode outer holder.

[0013] A group of relatively two-way ends of the five-way pipe are symmetrically provided with a quick interface, a tightening nut, and a tightening spiral tube in sequence. The quick interface and the five-way pipe are fixed by a buckle I, and the quick interface and the opposite end faces of the five-way pipe are sealed by a rubber sealing ring. The inner cavity wall of the quick interface is provided with an internal thread, and the tightening nut is connected to the inner cavity wall of the quick interface by a thread. The end face of the tightening nut located in the inner cavity of the quick interface corresponds to the outer end face of the electrode outer support, and an adjusting washer is provided between the end face in the inner cavity of the quick interface and the outer end face of the electrode outer support; the inner wall surface of the center hole of the tightening nut is provided with an internal thread, and the tightening spiral tube is passed through the center hole of the tightening nut and is connected to the inner wall surface of the center hole of the tightening nut by a thread. One end of the tightening spiral tube corresponds to the outer end face of the electrode inner support, and the electrode inner support is tightened and fixed by the tightening spiral tube;

[0014] The other two opposite ends of the five-way pipe are connected to the pipe of the experimental loop part through a snap; the fifth end vertically arranged on the five-way pipe is provided with an external thread, and the threaded pressure cap is connected to the fifth end through a threaded connection, and a reference electrode holder is provided in the inner cavity of the fifth pipe, and a rubber sealing ring IV is provided between the threaded pressure cap and the reference electrode holder, and one end of the reference electrode passes through the threaded pressure cap and extends into the inner cavity of the fifth pipe.

[0015] The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, the weightlessness test pipe section includes a conversion head, a buckle II, a weightlessness pipe, a weightlessness sample, a weightlessness sample gasket, and a rubber sealing ring V. The specific structure is as follows:

[0016] The weight loss samples are evenly arranged in the weight loss pipe, and adjacent weight loss samples are insulated and separated by weight loss sample gaskets. The weight loss samples are clamped to the adjacent weight loss sample gaskets. The two ends of the weight loss pipe are respectively connected to one end of an adapter through a snap II and sealed by a rubber sealing ring V. The other end of each adapter is connected to the pipe of the experimental loop part.

[0017] The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of the pipeline is provided with a horizontal pipeline pump, a cooler, a plastic hose II, a stainless steel braided pipe, and a plastic hose III in the cooling circuit part. The water inlet of the horizontal pipeline pump is connected to one end of the stainless steel braided pipe, and the other end of the stainless steel braided pipe extends into the bottom of the water reservoir. The water outlet of the horizontal pipeline pump is connected to one end of the plastic hose II, and the other end of the plastic hose II is connected to the experimental solution inlet end of the cooler. The experimental solution outlet end of the cooler is connected to the water reservoir through the plastic hose III.

[0018] In the pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, a cooler is provided with an inlet and an outlet for a cooling solution, so that the cooler is connected to an external cooling solution.

[0019] The design concept of the present invention is:

[0020] The present invention is based on an existing engineering problem: in pipeline transportation systems and pipe-flow cooling systems, the transported fluid medium will produce scouring and corrosion effects on the pipelines, often leading to pipeline corrosion, perforation and leakage, thereby causing the entire transportation system and equipment to stop operating, resulting in loss of life and property.

[0021] In order to avoid corrosion, perforation and leakage of pipelines, it is necessary to simulate the erosion and corrosion behavior of corresponding materials under corresponding media through experiments, obtain the corrosion law of corresponding materials under corresponding environments, and thus guide the selection of materials and the formulation of pipeline maintenance cycles.

[0022] To carry out erosion corrosion tests, corresponding equipment is needed. As described in the background art, at this stage, it is necessary to build a pipe flow erosion corrosion device with small size, stable operation and high testing efficiency.

[0023] In order to save energy and protect the environment, the equipment is designed and constructed to be as miniaturized and multifunctional as possible. Therefore, each pipe section adopts a replaceable modular design, and different pipe sections are connected by snap-fit ​​connections for easy disassembly and assembly. At the same time, the corresponding pipe sections can be replaced according to needs. For example, by replacing weightlessness test pipe sections of different diameters, the erosion and corrosion behavior of pipes of different specifications can be studied. By replacing ordinary elbows with elbows containing array electrodes, the erosion and corrosion behavior of pipes in the elbow area can be studied.

[0024] At present, in order to achieve higher test efficiency and better comparability, four electrochemical test sections and a weight loss test section that can be installed with multiple weight loss samples are set up, so that multiple different samples can be tested simultaneously at one time.

[0025] At present, in order to simulate the erosion corrosion behavior in more environments, such as simulating erosion corrosion under different flow rates, simulating dead water immersion and oxygen-rich immersion environments, valves and bypasses with valves are set between pipe sections. The erosion corrosion in different environments can be simulated by adjusting the opening and closing angles of the valves and the coordination between the valves.

[0026] The present invention has the following advantages and beneficial effects:

[0027] 1. The present invention adopts a modular design, and each pipe section of the experimental loop can be easily disassembled, assembled and re-modified.

[0028] 2. The test pipe section of the present invention is equipped with a valve, which can realize dead water immersion and oxygen-rich immersion by coordinating the opening and closing of the valve and the bypass water injection and ventilation, and realize flushing with different flow rates by controlling the opening and closing angle of the valve.

[0029] 3. The present invention can simultaneously perform electrochemical testing and weight loss testing on multiple pipe samples of the same or different types, which is more efficient than existing erosion corrosion test devices.

[0030] 4. Compared with traditional pipe flow experimental devices, the present invention occupies a smaller area and has lower operating costs. Compared with traditional rotating disc and jet experimental devices, the experimental conditions are more in line with actual pipe flow conditions.

[0031] 5. The present invention can design different types of test pipe sections according to needs to realize erosion corrosion research of samples with different materials, pipe diameters or elbows. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention.

[0033] Figure 2 This is a schematic diagram of the electrochemical test tube section structure of the present invention.

[0034] Figure 3 This is a schematic diagram of the weightlessness test pipe section structure of the present invention.

[0035] Figure 4 The open circuit potential (OCP) results for a sample after being flushed on the device for different times are shown in the figure. In the figure, the horizontal axis (Time) represents time (s), and the vertical axis (Ecorr) represents the open circuit potential (V / SCE).

[0036] Figure 5The following are the electrochemical impedance spectroscopy results of a sample after being flushed on the device for different times. In the figure, the horizontal axis Zreal represents the real impedance (Ω), and the vertical axis -Zimag represents the imaginary impedance (Ω).

[0037] Figure 6 The open circuit potential (OCP) results for the same polished sample after testing at four electrochemical test locations on the device for the same duration are shown. In the figure, the horizontal axis (Time) represents time (s), and the vertical axis (Ecorr) represents the open circuit potential (V / SCE).

[0038] In the figure: 1. Horizontal pipeline pump; 2. Cooler; 3. Pipe support; 4. Valve I; 5. Submersible pump; 6. Water reservoir; 7. Valve II; 8. Test system; 9. Valve III; 10. Electrochemical test pipe section I; 11. Electrochemical test pipe section II; 12. Weightlessness test pipe section; 13. Electrochemical test pipe section III; 14. Electrochemical test pipe section IV; 15. Valve IV; 16. Valve V; 17. Electromagnetic flowmeter; 18. Compression screw; 19. Compression nut; 20. Quick connector; 21. Buckle I; 22. Five-way pipe; 23. Counter electrode sample; 2 4. Working electrode sample; 25. Electrode outer support; 26. Adjusting gasket; 27. Electrode inner support; 28. Wire; 29. ​​Rubber sealing ring I; 30. Rubber sealing ring II; 31. Rubber sealing ring III; 32. Threaded pressure cap; 33. Reference electrode; 34. Rubber sealing ring IV; 35. Reference electrode holder; 36. Conversion head; 37. Buckle II; 38. Weightlessness pipe; 39. Weightlessness sample; 40. Weightlessness sample gasket; 41. Rubber sealing ring V; 42. Plastic hose I; 43. Plastic hose II; 44. Stainless steel braided hose; 45. Plastic hose III. DETAILED DESCRIPTION

[0039] like Figure 1 、 Figure 2 、 Figure 3As shown, the pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline of the present invention comprises an experimental loop part, a cooling loop part, and a test system 8. The water outlet of the submersible pump is connected to the inlet end of the experimental loop part through a plastic hose I42. The electrochemical test pipe sections of the experimental loop part are distributed on the upper and lower sides of the weightlessness test pipe section 12. The samples of the electrochemical test pipe sections are connected to the test system 8 through a wire. The outlet end of the experimental loop part is immersed below the liquid level of the water reservoir 6. The water inlet of the horizontal pipeline pump 1 of the cooling loop part extends into the bottom of the water reservoir 6 through a stainless steel braided tube 44. The water outlet of the horizontal pipeline pump 1 is connected to the water inlet of the cooler 2 through a plastic hose II43. The water outlet of the cooler 2 is connected to one end of the plastic hose III45. The other end of the plastic hose III45 is immersed below the liquid level of the water reservoir 6. A submersible pump 5 is used as the power to drive the experimental solution in the water reservoir 6 into the experimental loop part, which realizes the erosion corrosion simulation of the sample. The test data is obtained through the test system 8. A horizontal pipeline pump 1 is used as the power to drive the experimental solution in the water reservoir 6 into the cooling loop part for cooling.

[0040] The tube flow experimental device mainly includes: a horizontal pipeline pump 1, a cooler 2, a pipeline support 3, a valve I4, a submersible pump 5, a water reservoir 6, a valve II7, a test system 8, a valve III9, an electrochemical test pipe section I10, an electrochemical test pipe section II11, a weightlessness test pipe section 12, an electrochemical test pipe section III13, an electrochemical test pipe section IV14, a valve IV15, a valve V16, an electromagnetic flowmeter 17, a compression screw 18, a compression nut 19, a quick interface 20, a buckle I 21, five-way pipe 22, counter electrode sample 23, working electrode sample 24, electrode outer support 25, adjustment gasket 26, electrode inner support 27, wire 28, rubber sealing ring I29, rubber sealing ring II30, rubber sealing ring III31, threaded pressure cap 32, reference electrode 33, rubber sealing ring IV34, reference electrode holder 35, conversion head 36, buckle II37, weight loss pipe 38, weight loss sample 39, weight loss sample gasket 40, rubber sealing ring V41, etc. The specific structure is as follows:

[0041] The experimental loop part is provided with a water reservoir 6, a submersible pump 5, a plastic hose I42, an electromagnetic flowmeter 17, an electrochemical test pipe section (electrochemical test pipe section I10, electrochemical test pipe section II11, electrochemical test pipe section III13, electrochemical test pipe section IV14), and a weightlessness test pipe section 12. The submersible pump 5 is arranged at the bottom of the water reservoir 6. The water outlet of the submersible pump 5 is connected to one end of the plastic hose I42 through a stainless steel conical tube. The other end of the plastic hose I42 is equipped with a stainless steel quick-release hose connector. The quick-release hose connector and the plastic hose I42 are clamped by a stainless steel pipe clamp. The quick-release hose connector is connected to the inlet end of the experimental loop part through a buckle.

[0042] The upward pipeline of the experimental loop is equipped with an electromagnetic flowmeter 17, an electrochemical test pipe segment IV14, an electrochemical test pipe segment III13, a weightlessness test pipe segment 12, an electrochemical test pipe segment II11, and an electrochemical test pipe segment I10, arranged in order from bottom to top. Electromagnetic flowmeter 17 is secured to the pipe support 3 via a lifting device. Its two ends are connected to the experimental loop pipe via flanges welded with clips. A valve II7 is installed on the pipe segment connecting the electromagnetic flowmeter 17 and the plastic hose I42. A vertical bypass is also provided on this pipe segment, the lower end of which extends upward into the reservoir 6. A valve I4 is installed on this bypass. Valve I4 functions as a diversion valve. In conjunction with valve II7, the flow rate of the main experimental loop can be varied by adjusting the opening and closing angle.

[0043] A valve V16 is installed in the experimental loop's descending pipe, along with a vertical bypass. The bypass's lower port is located above reservoir 6. A valve IV15 is installed on the bypass. Valve IV15 is opened during the dead water soaking and oxygen-enriched soaking and water injection phases to ensure unobstructed flow. The lower port of the experimental loop's descending pipe serves as the experimental loop's outlet, submerged below the liquid level in reservoir 6.

[0044] The upward pipeline of the experimental loop part and the downward pipeline of the experimental loop part are parallel to each other. The upper port of the upward pipeline is connected to the upper port of the downward pipeline through a horizontal pipeline. A horizontal bypass is set on the horizontal pipeline. One end of the bypass is open. A valve III9 is ​​installed on the bypass. The function of valve III9 is ​​to open water injection ventilation when simulating oxygen-enriched immersion experiment, and to open water injection during dead water immersion experiment.

[0045] In addition, the pipeline of the experimental loop part is fixed by the pipeline bracket 3, the adjacent pipe sections of the experimental loop part are fixed by buckles, the adjacent pipe sections of the experimental loop part are waterproofly sealed by rubber sealing rings, and the inner wall of the pipeline of the experimental loop part is rust-proofed.

[0046] The cooling circuit is provided with a horizontal pipeline pump 1, a cooler 2, a plastic hose II43, a stainless steel braided tube 44, and a plastic hose III45. The water inlet of the horizontal pipeline pump 1 is connected to one end of the stainless steel braided tube 44, and the other end of the stainless steel braided tube 44 extends into the bottom of the water reservoir 6. The water outlet of the horizontal pipeline pump 1 is connected to one end of the plastic hose II43, and the other end of the plastic hose II43 is connected to the experimental solution inlet of the cooler 2. The experimental solution outlet of the cooler 2 is connected to the water reservoir 6 through the plastic hose III45. At the same time, the cooler 2 is provided with an inlet and an outlet for the cooling solution, so that the cooler 2 is connected to the external cooling solution, which has a better cooling effect. Moreover, the cooler 2 is not actively cooled, but is cooled by the external cooling solution.

[0047] like Figure 1 、 Figure 2 As shown, the electrochemical test tube segment I10, the electrochemical test tube segment II11, the electrochemical test tube segment III13, and the electrochemical test tube segment IV14 are all five-way structures, which include: a compression screw 18, a compression nut 19, a quick interface 20, a buckle I 21, a five-way pipe 22, a counter electrode sample 23, a working electrode sample 24, an electrode outer support 25, an adjustment washer 26, an electrode inner support 27, a wire 28, a rubber sealing ring I29, a rubber sealing ring II30, a rubber sealing ring III31, a threaded pressure cap 32, a reference electrode 33, a rubber sealing ring IV34, and a reference electrode support 35. The specific structure is as follows:

[0048] Electrode holders 25 are symmetrically inserted into the inner lumens of two opposing channels of a five-way pipe 22. A counter electrode sample 23 and a working electrode sample 24 are respectively disposed in the inner lumens of one electrode holder 25. The counter electrode samples 23 and the working electrode samples 24 are disposed opposite each other, with an electrode inner holder 27 inserted into the inner lumen of each electrode holder 25. The sides and backs of the counter electrode samples 23 and the working electrode samples 24 are sealed with glue to prevent water leakage. The backs of the counter electrode samples 23 and the working electrode samples 24 are respectively connected to a wire 28. Each wire 28 extends through the center hole of the electrode inner holder 27, and the extended end of the wire 28 is connected to the testing system 8. A rubber sealing ring II30 is disposed between the contact surface of the electrode holder 25 and the outer end surface of the two opposing channels of the five-way pipe 22, and a rubber sealing ring I29 is disposed between the contact surface of the electrode inner holder 27 and the outer end surface of the electrode holder 25.

[0049] A group of relatively two-way ends of the five-way pipe 22 are symmetrically provided with a quick interface 20, a tightening nut 19, and a tightening screw 18 in sequence. The quick interface 20 and the five-way pipe 22 are fixed by a buckle I21, and the quick interface 20 and the relative end faces of the five-way pipe 22 are sealed by a rubber sealing ring 31. The inner cavity wall of the quick interface 20 is provided with an internal thread, and the tightening nut 19 is connected to the inner cavity wall of the quick interface 20 by a thread. The end face of the tightening nut 19 located in the inner cavity of the quick interface 20 corresponds to the outer end face of the electrode outer support 25, and an adjusting washer 26 is provided between the end face in the inner cavity of the quick interface 20 and the outer end face of the electrode outer support 25; the inner wall surface of the center hole of the tightening nut 19 is provided with an internal thread, and the tightening screw 18 is passed through the center hole of the tightening nut 19 and is threadedly connected to the inner wall surface of the center hole of the tightening nut 19. One end of the tightening screw 18 corresponds to the outer end face of the electrode inner support 27, and the electrode inner support 27 is tightened and fixed by the tightening screw 18.

[0050] The other two opposite ends of the five-way pipe 22 are connected to the pipe of the experimental loop part through a snap; the fifth end portion vertically arranged on the five-way pipe 22 is provided with an external thread, and the threaded pressure cap 32 is connected to the fifth end portion through a thread, and a reference electrode holder 35 is provided in the inner cavity of the fifth channel, and a rubber sealing ring IV34 is provided between the threaded pressure cap 32 and the reference electrode holder 35, and one end of the reference electrode 33 passes through the threaded pressure cap 32 and extends into the inner cavity of the fifth channel.

[0051] like Figure 1 、 Figure 3 As shown, the weight loss test tube section 12 includes a conversion head 36, a buckle II 37, a weight loss pipe 38, a weight loss sample 39, a weight loss sample gasket 40, and a rubber sealing ring V41. The specific structure is as follows:

[0052] The weight loss samples 39 are evenly arranged in the weight loss pipe 38, and the adjacent weight loss samples 39 are insulated and separated by weight loss sample gaskets 40. The weight loss samples 39 are clamped with adjacent weight loss sample gaskets 40. The two ends of the weight loss pipe 38 are respectively connected to one end of an adapter 36 through a snap II37 and sealed by a rubber sealing ring V41. The other end of each adapter 36 is connected to the pipeline of the experimental loop part.

[0053] The working process of the present invention is as follows:

[0054] When conducting the flushing test, open valve V16, adjust the opening and closing angles of valves I4 and II7, close valves III9 and IV15, and the submersible pump 5 outputs power to drive the experimental solution in the water reservoir 6 into the pipeline of the experimental loop part, flowing through valve II7, electromagnetic flowmeter 17, electrochemical test pipe section IV14, electrochemical test pipe section III13, weightlessness test pipe section 12, electrochemical test pipe section II11, electrochemical test pipe section I10, valve V16, and finally flow back to the water reservoir 6. The electrochemical workstation in the test system 8 collects electrochemical signals, and the PC stores and analyzes the data.

[0055] Horizontal pipeline pump 1 delivers power, driving the experimental solution into the cooling circuit, through cooler 2, and ultimately back into reservoir 6. Cooler 2 connects to the cooling solution, allowing the cooling medium and flow rate to be adjusted according to experimental temperature requirements. By adjusting the opening and closing angles of valves I4 and II7, different experimental flow rates can be achieved.

[0056] During dead water immersion, open valve I4, valve III9, and valve IV15, close valve II7 and valve V16, and introduce the experimental solution into the pipe opening on the right side of valve III9. After the specified time, close valve I4. Stop introducing the solution after the electrochemical test pipe segment I10, electrochemical test pipe segment II11, weightlessness test pipe segment 12, electrochemical test pipe segment III13, and electrochemical test pipe segment IV14 are filled with the solution, and close valve III9 and valve IV15. The sealing time of the electrochemical test pipe segment I10, electrochemical test pipe segment II11, weightlessness test pipe segment 12, electrochemical test pipe segment III13, and electrochemical test pipe segment IV14 can be maintained according to the dead water immersion time required by the experiment, and electrochemical testing can be carried out during this period.

[0057] During oxygen-enriched immersion, open valve I4, valve III19, and valve IV15, close valve II7 and valve V16, and introduce the experimental solution into the pipe opening on the right side of valve III9. After the specified time, close valve I4. Stop introducing the solution after the electrochemical test pipe segment I10, electrochemical test pipe segment II11, weightlessness test pipe segment 12, electrochemical test pipe segment III13, and electrochemical test pipe segment IV14 are filled with the solution. Insert an air guide tube from the pipe opening on the right side of valve III9 into the liquid immersed in the electrochemical test segment IV14. Blow air at a certain rate at the specified time interval according to the experimental requirements to complete the oxygen-enriched immersion, during which electrochemical testing can be carried out.

[0058] like Figure 4 、 Figure 5 As shown in the figure, the electrochemical test results of a sample obtained over time show that the equipment can stably test the open circuit potential and electrochemical impedance spectroscopy with high requirements for system stability, and can reflect the evolution of the corrosion resistance of the sample over time under this condition, indicating that the equipment has good test stability.

[0059] like Figure 6 As shown in the figure, the electrochemical test results of the same sample were obtained at four electrochemical positions under the same test environment. It can be seen that the open circuit potentials of the four positions are very small and within the experimental error range, indicating that the four electrochemical positions of the device have test reproducibility. The same or different samples can be tested at the four electrochemical test positions at the same time, which greatly improves the experimental efficiency and makes the experimental data more convincing.

[0060] The results show that the present invention has the advantages of a pipe flow erosion-corrosion experimental device. It can study the axial erosion-corrosion behavior of the inner wall of the pipeline under conditions that truly simulate actual pipe flow conditions. It can accurately control test parameters such as temperature, flow rate, medium composition, and simulate the initial immersion environment of the pipeline. It can also simultaneously realize online electrochemical monitoring and weight loss testing of multiple identical or different samples.

Claims

1. A pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline, characterized in that: The device comprises an experimental loop part, a cooling loop part and a test system. The water outlet of the submersible pump is connected to the inlet end of the experimental loop part through a plastic hose I. The electrochemical test pipe sections of the experimental loop part are distributed on the upper and lower sides of the weightlessness test pipe section. The samples of the electrochemical test pipe sections are connected to the test system through a wire. The outlet end of the experimental loop part is immersed below the liquid surface of the water reservoir. The water inlet of the horizontal pipeline pump of the cooling loop part extends into the bottom of the water reservoir through a stainless steel braided pipe. The water outlet of the horizontal pipeline pump is connected to the water inlet of the cooler through a plastic hose II. The water outlet of the cooler is connected to one end of the plastic hose III. The other end of the plastic hose III is immersed below the liquid surface of the water reservoir. The experimental loop part is provided with a water reservoir, a submersible pump, a plastic hose I, an electromagnetic flowmeter, an electrochemical test pipe section I, an electrochemical test pipe section II, an electrochemical test pipe section III, an electrochemical test pipe section IV, and a weightlessness test pipe section. The submersible pump is arranged at the bottom of the water reservoir, and the water outlet of the submersible pump is connected to one end of the plastic hose I through a stainless steel conical tube, and the other end of the plastic hose I is connected to the inlet end of the experimental loop part; in the upward pipeline of the experimental loop part, an electromagnetic flowmeter, an electrochemical test pipe section IV, an electrochemical test pipe section III, a weightlessness test pipe section, an electrochemical test pipe section II, and an electrochemical test pipe section I are arranged in sequence from bottom to top, the electromagnetic flowmeter is fixed to the pipeline bracket through a lifting device, and both ends of the electromagnetic flowmeter are connected to the pipeline on the experimental loop through flanges welded with buckles; A horizontal pipeline pump, a cooler, a plastic hose II, a stainless steel braided pipe and a plastic hose III are provided in the cooling circuit part. The water inlet of the horizontal pipeline pump is connected to one end of the stainless steel braided pipe, and the other end of the stainless steel braided pipe extends into the bottom of the water reservoir. The water outlet of the horizontal pipeline pump is connected to one end of the plastic hose II, and the other end of the plastic hose II is connected to the experimental solution inlet of the cooler. The experimental solution outlet of the cooler is connected to the water reservoir through the plastic hose III.

2. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: A valve II is installed on the pipe section connecting the electromagnetic flowmeter and the plastic hose I, and a vertical bypass is arranged on the pipe section, the lower port of the bypass extends to the upper part of the water reservoir, and a valve I is installed on the bypass.

3. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: A valve V is installed in the downward pipeline of the experimental loop part, and a vertical bypass is arranged on the downward pipeline, the lower port of the bypass is located above the water reservoir, and a valve IV is installed on the bypass; the lower port of the downward pipeline of the experimental loop part is the outlet end of the experimental loop part, and the outlet end of the experimental loop part is immersed below the liquid level of the water reservoir.

4. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: The upward pipeline of the experimental loop part and the downward pipeline of the experimental loop part are parallel to each other, and the upper port of the upward pipeline is connected with the upper port of the downward pipeline through a horizontal pipeline. A horizontal bypass is arranged on the horizontal pipeline, one end of the bypass is open, and a valve III is installed on the bypass.

5. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: The pipelines in the experimental loop part are fixed by pipeline brackets, the adjacent pipe sections in the experimental loop part are fixed by buckles, the adjacent pipe sections in the experimental loop part are waterproofly sealed by rubber sealing rings, and the inner wall of the pipeline in the experimental loop part is rust-proofed.

6. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: Electrochemical test tube section I, electrochemical test tube section II, electrochemical test tube section III, and electrochemical test tube section IV are all five-way structures, and the five-way structure includes: a compression screw, a compression nut, a quick interface, a buckle, a five-way pipeline, a counter electrode sample, a working electrode sample, an electrode outer support, an adjustment gasket, an electrode inner support, a wire, a rubber sealing ring I, a rubber sealing ring II, a rubber sealing ring III, a threaded pressure cap, a reference electrode, a rubber sealing ring IV, and a reference electrode support. The specific structure is as follows: A group of electrode outer holders are symmetrically inserted into the inner cavities of two opposite channels of a five-way pipeline, and the counter electrode sample and the working electrode sample are respectively arranged in the inner cavity of one electrode outer holder, and the counter electrode sample and the working electrode sample are arranged opposite to each other. An electrode inner holder is inserted into the inner cavity of each electrode outer holder, and the backs of the counter electrode sample and the working electrode sample are respectively connected to a wire, and each wire extends through the central hole of the electrode inner holder, and the extended end of the wire is connected to the test system; a rubber sealing ring II is arranged between the contact surface of the electrode outer holder and the outer end surface of a group of opposite channels of the five-way pipeline, and a rubber sealing ring I is arranged between the contact surface of the electrode inner holder and the outer end surface of the electrode outer holder; A group of relatively two-way ends of the five-way pipe are symmetrically provided with a quick interface, a clamping nut, and a clamping spiral tube in sequence. The quick interface and the five-way pipe are fixed by a buckle I, and the quick interface and the opposite end faces of the five-way pipe are sealed by a rubber sealing ring. The inner cavity wall of the quick interface is provided with an internal thread, and the clamping nut is connected to the inner cavity wall of the quick interface by a thread. The end face of the clamping nut located in the inner cavity of the quick interface corresponds to the outer end face of the electrode outer support, and an adjustment washer is arranged between the end face in the inner cavity of the quick interface and the outer end face of the electrode outer support; the inner wall surface of the center hole of the clamping nut is provided with an internal thread, and the clamping spiral tube is penetrated through the center hole of the clamping nut and is connected to the inner wall surface of the center hole of the clamping nut by a thread, one end of the clamping spiral tube corresponds to the outer end face of the electrode inner support, and the electrode inner support is clamped and fixed by the clamping spiral tube; The other two opposite ends of the five-way pipe are connected to the pipe of the experimental loop part through a snap; the fifth end vertically arranged on the five-way pipe is provided with an external thread, the threaded pressure cap is connected to the fifth end through a thread, a reference electrode holder is arranged in the inner cavity of the fifth channel, a rubber sealing ring IV is arranged between the threaded pressure cap and the reference electrode holder, and one end of the reference electrode passes through the threaded pressure cap and extends into the inner cavity of the fifth channel.

7. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: The weightlessness test pipe section includes a conversion head, a buckle II, a weightlessness pipe, a weightlessness sample, a weightlessness sample gasket, and a rubber sealing ring V. The specific structure is as follows: The weight loss samples are evenly arranged in the weight loss pipe, and adjacent weight loss samples are insulated and separated by weight loss sample gaskets. The weight loss samples are clamped together with adjacent weight loss sample gaskets. The two ends of the weight loss pipe are respectively connected to one end of an adapter through a buckle II and sealed by a rubber sealing ring V. The other end of each adapter is connected to the pipe of the experimental loop part.

8. The pipe flow experimental device for simulating axial erosion corrosion of the inner wall of a pipeline according to claim 1, characterized in that: The cooler is provided with an inlet and an outlet for a cooling solution, so that the cooler is connected to an external cooling solution.

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