Temperature-controllable and oxygen-controllable scouring experiment device and method for simulating deep sea environment

Abstract

The invention belongs to the technical field of material environment corrosion experiments, and particularly relates to a temperature-controllable and oxygen-controllable scouring experiment device and method for simulating a deep sea environment, which are suitable for simulating complex fluid environments such as deep sea, rivers, oil fields and the like. The device is provided with a washing system, a temperature control system, a dissolved oxygen control system, an attack angle adjusting system and an electrochemical testing system, a sample on a sample clamp is used as a working electrode, and the sample clamp is mounted on a clamp fixer of the attack angle adjusting system; an electrochemical workstation of the electrochemical testing system is respectively connected with a working electrode, a reference electrode and a counter electrode through electrode leads, the working electrode, the reference electrode and the counter electrode are positioned in a solution tank, and a reducing nozzle of the flushing system corresponds to the working electrode; and a thermocouple of the temperature control system and a dissolved oxygen sensor of the dissolved oxygen control system are arranged in the solution tank. The device can comprehensively simulate the low-temperature, low-oxygen and high-flow-speed environment of the deep sea, and can research the influence of different fluid parameters on material damage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of material environmental corrosion experiments, and particularly relates to a controllable temperature and oxygen-flushing experimental device and method for simulating a deep-sea environment. BACKGROUND

[0002] The deep sea is rich in oil and gas, mineral and biological resources, and is an important strategic space for the long-term development of a country. With the rapid development of China's deep-sea exploration and development capabilities, the reliability of deep-sea equipment (such as manned / unmanned deep-sea submersibles, seabed space stations, energy exploitation systems, etc.) has become a key limiting factor. Key components are faced with extremely severe multi-factor coupled corrosion challenges in the deep-sea environment: first, the bottom layer of the deep sea is in a low-temperature environment of 2-10°C all year round, and low temperature can significantly change the electrochemical activity and reaction rate of materials, affecting their corrosion mechanism. Second, as the depth increases, the dissolved oxygen content of seawater can drop sharply to below 1 mg / L, and this dramatic change in chemical environment causes the material to change from a passivation state to an active corrosion state, fundamentally changing the corrosion type and rate. In addition, key components such as heat exchange pipelines may be in service in a high-speed flowing seawater environment, and there are often solid substances such as silt and mineral particles suspended in seawater. This "seawater + solid phase" scouring effect can continuously damage the protective corrosion product film formed on the surface of the material, exacerbating the loss of the material, and leading to synergistic damage of the material by scouring corrosion.

[0003] The coupling of low temperature, low oxygen, and high flow rate scouring can dramatically accelerate the failure process of the heat exchange pipeline, possibly leading to pipe wall thinning, perforation, or even rupture, causing serious accidents such as medium leakage and system malfunction, threatening equipment safety and causing huge economic losses. Therefore, it is of great engineering significance and strategic urgency to accurately evaluate and predict the corrosion behavior of materials under such real deep-sea working conditions during the material research and development and equipment design stages.

[0004] However, the current domestic and foreign commercial scouring corrosion experimental devices have significant shortcomings in simulating the core environmental factors of the deep sea: most of the equipment only works at room temperature, and a few have heating functions, but they generally lack efficient and stable refrigeration capabilities, and cannot simulate the low-temperature environment of 2-10°C in the deep sea; almost all existing devices lack monitoring and control functions for the dissolved oxygen content of the medium, and experiments are usually carried out in air-saturated media, which is fundamentally different from the low-oxygen environment in the deep sea; existing technologies can only simulate single or partial factors, and cannot achieve the simultaneous loading and precise control of low temperature, low oxygen, and scouring, making it difficult to reproduce the real deep-sea coupled corrosion scenario.

[0005] The patent with publication number CN220751886U proposes a flow scouring corrosion experiment device simulating deep-sea environment. The temperature control only reduces the temperature of the cooling liquid in the jacket layer through a circulating cooling device, thereby reducing the temperature in the autoclave. It cannot achieve high-temperature environment simulation and is difficult to cover the experimental needs of different temperature environments in deep sea. The scouring system rotates the shaft and blades driven by a motor to generate water flow to scour the sample. The flow rate adjustment depends on the change of motor speed, which cannot adjust the angle between the sample and the water flow direction, and cannot simulate the influence of water flow direction change on sample scouring corrosion in deep sea. The oxygen control system only reduces the dissolved oxygen by introducing nitrogen gas from a nitrogen gas cylinder. The dissolved oxygen control precision is low, which cannot accurately maintain the stability of dissolved oxygen content during the experiment, and it is difficult to simulate the dissolved oxygen gradient environment at different depths in deep sea.

[0006] The patent with publication number CN216791899U proposes a deep-sea low-temperature environment simulation device. It only realizes low-temperature (2-4℃) control through an ice maker and cooling pipeline, and cannot achieve wide-range temperature adjustment, which cannot meet the experimental needs of simulating different temperature gradient deep-sea environments. The device can only simulate high-pressure and low-temperature environments, lacks a scouring system, and cannot simulate the scouring effect of seawater flow on materials in deep sea. At the same time, it cannot adjust the dissolved oxygen content in the experimental environment, cannot simulate the complex environment of deep-sea multi-factor (low temperature, high pressure, scouring, and low oxygen) coupling, and cannot meet the experimental research of deep-sea material corrosion and scouring synergy.

[0007] The patent with publication number CN103115862A proposes a corrosion test device and test method simulating deep-sea environment. In terms of temperature control, it only realizes temperature reduction through a refrigeration system composed of a condenser pipe, a compressor, and a condenser, which cannot achieve high-temperature environment simulation and cannot meet the wide-temperature-range experimental needs of different deep-sea regions (such as near-seabed low temperature and relatively high temperature near hydrothermal vents). The scouring system relies on a stirring motor to drive stirring blades to realize seawater flow. The flow rate adjustment is only realized by changing the stirring motor speed, which has a narrow adjustment range and low precision, cannot simulate extreme scouring scenarios with different flow rates in deep sea, and the device is not applied to jet test scenarios. The oxygen control system only adjusts the dissolved oxygen by introducing air from an air pump and nitrogen from a nitrogen cylinder, which has a limited dissolved oxygen control range and poor precision, and cannot accurately simulate deep-sea low-dissolved-oxygen environment.

[0008] Therefore, it is of great significance to develop a device that can accurately simulate low-temperature and ultra-low-oxygen environments and simultaneously perform scouring experiments, to break through the evaluation technology bottleneck of deep-sea heat exchanger pipe materials and support the independent and controllable research and development of deep-sea equipment in China. SUMMARY

[0009] In view of the technical deficiencies of the existing deep-sea erosion corrosion experimental device in temperature control, dissolved oxygen regulation and multi-factor coupling, the purpose of the present application is to provide a controllable temperature and oxygen erosion experimental device and method for simulating deep-sea environment, which can simulate deep-sea low temperature, low oxygen and high-speed erosion environment, accurately regulate the temperature, dissolved oxygen content, flow rate and attack angle of the erosion medium, and can integrate an electrochemical test system to realize multifunctional erosion experiment, solving the key technical bottleneck that the existing equipment cannot truly reproduce the deep-sea multi-factor coupling corrosion environment.

[0010] The technical solution of the present application is:

[0011] A controllable temperature and oxygen erosion experimental device for simulating deep-sea environment, characterized in that the device is provided with an erosion system, a temperature control system, a dissolved oxygen control system, an attack angle adjustment system and an electrochemical test system, wherein a sample on a sample clamp is used as a working electrode, the sample clamp is installed on a clamp fixator of the attack angle adjustment system, an electrochemical workstation of the electrochemical test system is connected to the working electrode, a reference electrode and a counter electrode through electrode leads, the working electrode, the reference electrode and the counter electrode are located in a solution tank, a variable diameter nozzle of the erosion system corresponds to the working electrode, and a thermocouple of the temperature control system and a dissolved oxygen sensor of the dissolved oxygen control system are arranged in the solution tank.

[0012] The controllable temperature and oxygen erosion experimental device for simulating deep-sea environment comprises a centrifugal pump, a pressure gauge, a flowmeter, a material propeller, a flow controller, a thermocouple, a valve, a temperature controller, a stirrer, an electrochemical workstation, an oxygen concentration controller, a gas source, a dissolved oxygen sensor, a valve, a filter, a sand collector, a variable diameter nozzle, a working electrode, a reference electrode, a counter electrode, a heating / cooling pipe, a microporous aeration pipe, a solution tank and an attack angle controller, and the specific structure is as follows:

[0013] The solution tank is provided with a thermocouple, a dissolved oxygen sensor, a filter, a sand collector, a variable-diameter nozzle, a working electrode, a reference electrode, a counter electrode, a heating / cooling pipe, a microporous aeration pipe, and stirring blades, wherein the variable-diameter nozzle has a reverse T-shaped tee structure, one end of the horizontal direction of the variable-diameter nozzle is connected to the outlet of a centrifugal pump through a pipeline, the pipeline connected to the outlet of the centrifugal pump is sequentially provided with a pressure gauge, a flow meter connected to a flow controller, and a valve, the other end of the horizontal direction of the variable-diameter nozzle is connected to the working electrode installed on a sample clamp through a nozzle, the upper end of the vertical direction of the variable-diameter nozzle is connected to the sand collector, a valve for adjusting the sand entering the variable-diameter nozzle is arranged on the upper end of the vertical direction, and the sand collector has a funnel shape and is provided with a material propeller with adjustable speed at the upper end; the lower part of the inner cavity of the solution tank is horizontally provided with the microporous aeration pipe, the bottom of the inner cavity of the solution tank has a funnel shape, the filter is arranged below the microporous aeration pipe in the funnel-shaped inner cavity of the solution tank, the lower end outlet of the solution tank is connected to a horizontal pipeline in a vertical manner, the horizontal pipeline on one side of the lower end outlet of the solution tank is connected to the inlet of the centrifugal pump, and the horizontal pipeline on the other side of the lower end outlet of the solution tank is a sewage pipe provided with a valve.

[0014] The thermocouple and the heating / cooling pipe are respectively connected to a temperature controller outside the solution tank through lead wires, the dissolved oxygen sensor is connected to an oxygen concentration controller outside the solution tank through a lead wire, the output end of the oxygen concentration controller is connected to a gas source, the gas outlet of the gas source is connected to the microporous aeration pipe through a pipeline, the stirring blades are connected to the output end of a stirrer outside the solution tank through a vertical stirring shaft, the sample clamp of the working electrode is installed on a clamp fixer of an attack angle adjusting system, the angle of the working electrode is adjusted by a clamp fixer through an attack angle controller outside the solution tank, and the working electrode, the reference electrode, and the counter electrode are respectively connected to an electrochemical workstation outside the solution tank through electrode lead wires.

[0015] The controllable temperature and oxygen-flushing experimental device for simulating a deep-sea environment comprises a centrifugal pump, a variable-diameter nozzle connected to the outlet of the centrifugal pump, a sample clamp for fixing a working electrode, a solution tank for storing a flushing medium, and a flow controller, wherein the centrifugal pump is connected to the variable-diameter nozzle through frequency conversion control to realize the regulation of a flow rate of 1-20 m / s; the variable-diameter nozzle has a replaceable structure and two or more outlet diameters, the variable-diameter nozzle is directly aimed at the surface of the working electrode, and the flushing medium is artificial seawater, NaCl aqueous solution, or a simulated solution with specific components.

[0016] The temperature control system of the controllable temperature and oxygen flushing experimental device for simulating deep-sea environment comprises a heating / cooling pipe, a thermocouple and a temperature controller arranged in the solution tank, the temperature controller receives the signal of the thermocouple and controls the working of the heating / cooling pipe, so that the temperature of the flushing medium can be adjusted in the range of 2-90 DEG C with the accuracy of ±2 DEG C; the refrigeration element is a semiconductor refrigerator or an external circulating cooling unit, and the heating element is a titanium metal heating rod or a quartz heating pipe.

[0017] The dissolved oxygen control system of the controllable temperature and oxygen flushing experimental device for simulating deep-sea environment comprises a gas source, a microporous aeration pipe, a dissolved oxygen sensor and an oxygen concentration controller, the oxygen concentration controller receives the signal of the dissolved oxygen sensor and controls the electromagnetic valve for gas input, so that the dissolved oxygen content in the flushing medium can be controlled in the range of 0.5 ppm to saturated oxygen; the gas source is a high-purity nitrogen cylinder or a high-purity argon cylinder, and the microporous aeration pipe is a titanium alloy microporous aeration head.

[0018] The attack angle adjusting system of the controllable temperature and oxygen flushing experimental device for simulating deep-sea environment comprises a clamp fixer for fixing the sample clamp, an attack angle controller and an angle sensor corresponding to the working electrode, so that the stepless adjustment and locking of the attack angle between the surface of the working electrode and the flushing flow beam can be realized; the attack angle controller receives the signal of the current attack angle of the working electrode collected by the angle sensor in real time, and sends a command to the worm gear mechanism, the clamp fixer is driven by the worm gear mechanism, and the attack angle adjusting accuracy is better than ±1 DEG.

[0019] The electrochemical test system of the controllable temperature and oxygen flushing experimental device for simulating deep-sea environment comprises a working electrode, a reference electrode, a counter electrode embedded in the sample clamp and an electrochemical workstation, the working electrode, the reference electrode and the counter electrode are connected to the electrochemical workstation through electrode leads, so that the online electrochemical monitoring during the flushing process can be realized.

[0020] The central control system of the controllable temperature and oxygen flushing experimental device for simulating deep-sea environment is in communication connection with the controllers of the flushing system, the temperature control system, the dissolved oxygen control system and the attack angle adjusting system, and is used for setting and displaying the flow rate, the temperature, the dissolved oxygen content and the attack angle parameters.

[0021] A controllable temperature and oxygen flushing experimental method for simulating deep-sea environment, comprising the following steps:

[0022] Step 1: preparing the flushing medium and injecting it into the solution tank;

[0023] Step 2: setting the target temperature, the target dissolved oxygen content, the target flow rate and the attack angle through the central control system;

[0024] Step 3: starting the temperature controller and the oxygen concentration controller, and waiting for the temperature and the oxygen content of the flushing medium to be stable to the set values;

[0025] Step 4: Start the centrifugal pump, adjust to the target flow rate through the flow controller, and conduct the scouring experiment;

[0026] Step 5: During the scouring process, conduct online electrochemical monitoring through the external electrochemical workstation;

[0027] Step 6: After the experiment is completed, sequentially stop the centrifugal pump, temperature controller, and oxygen concentration controller.

[0028] The temperature-controllable and oxygen-controllable scouring experiment method simulates the deep-sea environment, in which, in step 3, the dissolved oxygen content is reduced to the ppm level by introducing gas into the scouring medium to simulate the low-oxygen environment of the deep sea, and the medium temperature is reduced to 5-10 DEG C by controlling the refrigeration element to simulate the low-temperature environment of the deep sea; in step 4, the flow rate of the flow beam emitted from the variable-diameter nozzle is stabilized at any value in the range of 1-20 m / s by replacing the variable-diameter nozzle and adjusting the power of the centrifugal pump; in step 5, the online electrochemical monitoring includes one or more than two of open circuit potential, dynamic potential polarization, constant potential polarization, and electrochemical impedance spectroscopy.

[0029] The design idea of the present application is:

[0030] The device of the present application comprises a multiphase flow scouring system, a high-precision temperature control system, and a dynamic dissolved oxygen control system; the temperature control system realizes rapid cooling and accurate stabilization of the scouring medium in the range of 2 DEG C to 90 DEG C by integrating refrigeration and heating technologies, and can especially simulate the low-temperature environment of 2-10 DEG C of the deep sea; the dissolved oxygen control system accurately regulates the oxygen content in the medium from 0.5 ppm to the wide range of saturated oxygen through the linkage of gas bubbling and dissolved oxygen sensor closed-loop feedback, and simulates the low-oxygen environment of the deep sea. In addition, the scouring system realizes scouring at a flow rate of 1-20 m / s through a high-power centrifugal pump and a variable-diameter nozzle; the attack angle adjustment system can accurately set the attack angle of the sample to 0-90 DEG; the electrochemical test system is externally connected to an electrochemical workstation to realize online electrochemical monitoring during the scouring process.

[0031] The innovation points of the present application mainly lie in the following aspects:

[0032] (1) Integrated high-precision temperature control system

[0033] The semiconductor refrigeration and heating integrated module realizes accurate temperature control of the experimental medium in the range of 2-90 DEG C. This system has broken through the technical difficulties in simulating the deep-sea low-temperature environment (2-10 DEG C), and the temperature control accuracy can reach ±2 DEG C, and long-term stability can be maintained under low-temperature conditions. Compared with the prior art, the present system first realizes accurate and stable simulation of the deep-sea low-temperature environment, and provides a reliable guarantee for the study of the corrosion behavior of materials under low-temperature conditions.

[0034] (2) Dynamic dissolved oxygen closed-loop detection and control system

[0035] The application innovatively designs a closed-loop control system based on gas bubbling and real-time monitoring of dissolved oxygen sensors, real-time monitoring of medium dissolved oxygen content by high-precision dissolved oxygen sensors (measurement range 0.5-20 ppm), dynamic adjustment of the amount and rate of high-purity nitrogen / argon, and realization of precise control of the dissolved oxygen content in the range of 0.5 ppm to saturated oxygen. The application solves the technical gap of the complete lack of dissolved oxygen regulation and control capability of existing devices, and can truly simulate the influence of deep-sea low-oxygen environment on material corrosion behavior.

[0036] Through the organic combination of the above innovative points, the application successfully solves the key technical problems in deep-sea scouring corrosion experiments, can truly simulate the complex environment of deep-sea low temperature, low oxygen and high-speed scouring, and provides indispensable technical support for the research and development, performance evaluation and life prediction of deep-sea equipment materials. Compared with the prior art, the application has significant progress in environmental simulation authenticity, parameter control precision and experimental method scientificity, and fills the technical gap in this field.

[0037] The advantages and beneficial effects of the application are:

[0038] 1. The application can truly reproduce the multi-factor coupled environment of different regions (low-temperature seabed, hydrothermal vent periphery, different flow rate sea areas) in deep sea by precise temperature control (±2℃) in a wide temperature range (2-90℃), flow rate adjustment in a wide range (1-20m / s), stepless adjustment of attack angle in the range of 0-90°, and precise oxygen control in the range of 0.5ppm to saturation oxygen, solving the problem of single simulation scene and low precision of existing devices, and providing more actual working condition environment conditions for deep-sea material experiments.

[0039] 2. The application integrates an electrochemical test system, which can obtain electrochemical corrosion parameters of the sample in real time during the experiment, dynamically reflects the change of the corrosion process, and compared with the existing device which can only obtain data by post-experiment analysis, the data is more comprehensive and timely, providing key data support for in-depth research on deep-sea material corrosion mechanism and scouring corrosion synergy.

[0040] 3. The wide range of temperature, flow rate, attack angle and dissolved oxygen adjustment capability of the application makes the device meet the testing needs of different deep-sea materials (such as pipeline steel, titanium alloy, composite material) under different experimental conditions, and the applicable environment covers deep-sea material corrosion performance test, scouring corrosion mechanism research, material life prediction, etc., solving the problem of narrow application range of existing devices.

[0041] 4. The central controller is used to realize automatic control of each system of the application, reducing the manual operation error. At the same time, the stability of the parameters during the experiment is ensured, the experimental data has good repeatability and high reliability, the experimental cost is reduced, and the experimental efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 This is a schematic diagram of the overall structure of the scouring experimental device of the present invention.

[0043] Figure 2 for Figure 1 A magnified view of a portion of the image.

[0044] The attached figures are labeled as follows: 1-Centrifugal pump; 2-Pressure gauge; 3-Flow meter; 4-Flow controller; 5-Thermocouple; 6-Valve; 7-Temperature controller; 8-Agitator; 9-Electrochemical workstation; 10-Oxygen concentration controller; 11-Gas source; 12-Dissolved oxygen sensor; 13-Valve; 14-Filter; 15-Clamp holder; 16-Variable diameter nozzle; 17-Working electrode; 18-Reference electrode; 19-Counter electrode; 20-Heating / cooling pipe; 21-Microporous aeration pipe; 22-Solution tank; 23-Angle of attack controller; 24-Material propeller; 25-Agitator blade; 26-Scribble medium; 27-Sand collector; 28-Sample clamp; 29-Angle sensor. Detailed Implementation

[0045] In its specific implementation, this invention proposes a temperature- and oxygen-controlled flushing experimental device simulating a deep-sea environment. It comprises a flushing system, a temperature control system, a dissolved oxygen control system, an angle-of-attack adjustment system, an electrochemical testing system, and a central control system. The sample on the sample holder serves as the working electrode. The sample holder is mounted on the clamping fixture of the angle-of-attack adjustment system. The electrochemical workstation of the electrochemical testing system is connected to the working electrode, reference electrode, and counter electrode via electrode leads. The working electrode, reference electrode, and counter electrode are located within a solution tank. The variable-diameter nozzle of the flushing system corresponds to the working electrode. The thermocouple of the temperature control system and the dissolved oxygen sensor of the dissolved oxygen control system are located within the solution tank. The central control system communicates with the controllers of the flushing system, temperature control system, dissolved oxygen control system, and angle-of-attack adjustment system, and is used to set and display flow rate, temperature, dissolved oxygen content, and angle-of-attack parameters.

[0046] like Figures 1-2 As shown, the scouring experimental apparatus of this invention mainly includes: a centrifugal pump 1, a pressure gauge 2, a flow meter 3, a flow controller 4, a thermocouple 5, a valve 6, a temperature controller 7, a stirrer 8, an electrochemical workstation 9, an oxygen concentration controller 10, a gas source 11, a dissolved oxygen sensor 12, a valve 13, a filter 14, a clamp holder 15, a variable diameter nozzle 16, a working electrode 17, a reference electrode 18, a counter electrode 19, a heating / cooling pipe 20, a microporous aeration pipe 21, a solution tank 22, an angle of attack controller 23, a material propeller 24, stirring blades 25, a scouring medium 26, and a sand collector 27, etc., with the specific structure as follows:

[0047] The solution tank 22 is provided with a thermocouple 5, a dissolved oxygen sensor 12, a filter 14, a clamp holder 15, a variable diameter nozzle 16, a working electrode 17, a reference electrode 18, a counter electrode 19, a heating / cooling pipe 20, a microporous aeration pipe 21, and a stirring blade 25. The variable diameter nozzle 16 has a reverse T-shaped three-way structure, and one end of the horizontal direction of the variable diameter nozzle 16 is connected to the outlet of the centrifugal pump 1 through a pipeline. The pipeline connected to the outlet of the centrifugal pump 1 is sequentially provided with a pressure gauge 2, a flow meter 3 connected to a flow controller 4, and a valve 6. The other end of the horizontal direction of the variable diameter nozzle 16 is connected to the working electrode 17 installed on the sample clamp 28 through a nozzle. The upper end of the vertical direction of the variable diameter nozzle 16 corresponds to the sand collector 27. A valve for adjusting the sand entering the variable diameter nozzle 16 is arranged on the vertical direction. The sand collector 27 has a funnel shape, and is provided with a speed-adjustable micro material propeller 24 above. The material propeller 24 is filled with sand, and the sand can be injected into the variable diameter nozzle 16 through the sand collector 27 as needed. The lower part of the inner cavity of the solution tank 22 is horizontally provided with the microporous aeration pipe 21. The bottom of the inner cavity of the solution tank 22 is funnel-shaped. The filter 14 is arranged below the microporous aeration pipe 21 in the funnel-shaped inner cavity of the solution tank 22. The lower end outlet of the solution tank 22 is connected to a horizontal pipeline in a vertical manner. The horizontal pipeline on one side of the lower end outlet of the solution tank 22 is connected to the inlet of the centrifugal pump 1. The horizontal pipeline on the other side of the lower end outlet of the solution tank 22 is a drain pipe provided with a valve 13.

[0048] The thermocouple 5 and the heating / cooling pipe 20 are respectively connected to the temperature controller 7 outside the solution tank 22 through lead wires, for real-time measurement of the temperature of the scouring medium 26 in the solution tank 22. The dissolved oxygen sensor 12 is connected to the input end of the oxygen concentration controller 10 outside the solution tank 22 through a lead wire. The output end of the oxygen concentration controller 10 is connected to the gas source 11, for controlling the switch of the gas source 11. The gas outlet of the gas source 11 is connected to the microporous aeration pipe 21 through a pipeline. The stirring blade 25 is connected to the output end of the stirrer 8 outside the solution tank 22 through a vertical stirring shaft. The stirring blade 25 is driven by the stirrer 8 to stir the scouring medium 26 in the solution tank 22. The sample clamp 28 of the working electrode 17 is installed on the clamp holder 15 of the attack angle adjusting system. The angle of the working electrode 17 is adjusted by the attack angle controller 23 outside the solution tank 22 through the clamp holder 15. The working electrode 17, the reference electrode 18, and the counter electrode 19 are respectively connected to the electrochemical workstation 9 outside the solution tank 22 through electrode lead wires, for online electrochemical monitoring of the sample.

[0049] The flushing system comprises a centrifugal pump 1, a variable-diameter nozzle 16 connected to the outlet of the centrifugal pump 1, a sample clamp 28 for fixing a sample (working electrode 17) to be tested, a solution tank 22 for storing a flushing medium 26, and a flow controller 4; the centrifugal pump 1 is a high-power centrifugal pump, which is matched with the variable-diameter nozzle through frequency conversion control to realize flow rate regulation of 1-20 m / s; the variable-diameter nozzle has a replaceable structure and has two or more outlet diameters to adapt to different flow rate requirements. The variable-diameter nozzle is replaceable, and by selecting nozzles with different diameters and cooperating with the centrifugal pump, the flow rate of the flushing medium can be accurately controlled in a wide range to simulate the water flow rate in different deep sea areas. The variable-diameter nozzle is fixedly installed, and the jetting direction thereof directly aims at the surface of the sample. This design can generate a stable and controllable directional flow beam to ensure that the flushing force can accurately act on the sample, thereby truly simulating the flushing conditions of the water flow on the material in the deep sea.

[0050] The flushing medium 26 is artificial seawater, NaCl aqueous solution or a simulated solution with specific components. The flushing medium can contain sand particles (such as simulating a deep sea sand-containing water flow environment). The solution tank 22 is provided with a filter 14 for collecting, separating and recycling the sand particles in the flushed sand-containing medium, avoiding sand particle deposition and blockage, preventing the sand particles in the flushed medium from depositing at the bottom of the solution tank 22, the pipeline or the variable-diameter nozzle 16, ensuring smooth circulation of the flushing medium and stable flow rate; the sand particles separated by the filter 14 can be collected and taken out; the filter 14 can screen the collected sand particles to ensure that the particle size and concentration of the recycled sand particles are consistent with the initial experimental conditions, avoid fluctuations in experimental data caused by changes in the state of the sand particles, and improve the repeatability and reliability of the experiment.

[0051] The output end of the stirrer 8 (such as a motor) is connected to the stirring blade 25 through a stirring shaft to realize uniform composition of the flushing medium. When the flushing medium contains multiple components such as sand particles and additives, the stirrer drives the stirring blade 25 to rotate to make the temperature of the corrosion medium uniform at each position, thereby improving the accuracy of the experimental data. At the same time, in cooperation with the temperature control system and the dissolved oxygen control system, the stirrer 8 can promote the convection of the medium in the solution tank 22, so that the temperature effect of the heating / cooling pipe and the dissolved oxygen concentration adjusted by the gas are uniformly distributed in the medium, avoiding local temperature and dissolved oxygen deviation, and ensuring stable experimental environment parameters.

[0052] The temperature control system comprises heating elements and cooling elements (heating / cooling pipes 20) arranged in the solution tank 22, a temperature sensor (thermocouple 5) and a temperature controller 7. The temperature controller 7 receives the signal of the thermocouple 5 and controls the operation of the heating / cooling pipes 20 to make the temperature of the flushing medium 26 adjustable in the range of 2-90°C with an accuracy range of ±2°C. The cooling element is a semiconductor cooler or an external circulating cooling unit, and the heating element is a titanium metal heating rod or a quartz heating pipe.

[0053] The dissolved oxygen control system comprises a gas source 11, a microporous aeration pipe 21, a dissolved oxygen sensor 12 and an oxygen concentration controller 10, the oxygen concentration controller 10 receives the signal of the dissolved oxygen sensor 12 and controls the electromagnetic valve of the gas (N2 or Ar) inlet, so that the dissolved oxygen content in the scouring medium is controllable in the range of 0.5 ppm to saturated oxygen; wherein the gas source 11 is a high-purity nitrogen cylinder or a high-purity argon cylinder; the microporous aeration pipe 21 is a titanium alloy microporous aeration head, the pore diameter is 0.3-0.6 mm, and the pore density is 20000 / m 2 .

[0054] The attack angle adjusting system comprises a clamp fixer 15 for fixing the sample clamp 28, an attack angle controller 23 and an angle sensor 29 corresponding to the sample, and realizes stepless adjustment and locking of the attack angle between the sample surface and the scouring flow beam in the range of 0-90°; the attack angle controller needs to receive the signal of the angle sensor 29 (real-time collection of the current attack angle of the sample) and send an instruction to the worm gear mechanism, and the clamp fixer 15 adjusts the left and right angles of the working electrode through the worm gear mechanism, and the attack angle adjusting precision is better than ±1°. The sample clamp 28 adjusts the front and back distance of the working electrode, the clamp fixer 15 adjusts the left and right angles of the working electrode, and the scouring angle between the scouring water flow and the sample is controlled.

[0055] The electrochemical test system comprises a working electrode 17, a reference electrode 18, a counter electrode 19 embedded in the sample clamp 28 and an electrochemical workstation 9, the working electrode 17, the reference electrode 18 and the counter electrode 19 are connected to the electrochemical workstation 9 through electrode leads respectively, and online electrochemical monitoring in the scouring process is realized.

[0056] As shown in Figures 1-2 , the method for carrying out the scouring experiment by the scouring experiment device of the present application comprises the following steps:

[0057] Step 1: prepare the scouring medium 26 and inject it into the solution tank 22;

[0058] Step 2: set the target temperature, the target dissolved oxygen content, the target flow rate and the attack angle through the central control system;

[0059] Step 3: start the temperature controller 7 and the oxygen concentration controller 10, and wait for the temperature and the oxygen content of the scouring medium 26 to be stable to the set values; in step 3, the gas is inhaled into the scouring medium 26 until the dissolved oxygen content is reduced to the ppm level (0.5 ppm to 10 ppm), so as to simulate the deep-sea low-oxygen environment; the medium temperature is reduced to 5-10℃ by controlling the refrigeration element, so as to simulate the deep-sea low-temperature environment.

[0060] Step 4: start the centrifugal pump 1, adjust to the target flow rate through the flow rate controller 4, and carry out the scouring experiment; in step 4, the flow rate of the flow beam emitted from the variable-diameter nozzle 16 is stabilized at any value in the range of 1-20 m / s by replacing the variable-diameter nozzle 16 and adjusting the power of the centrifugal pump 1.

[0061] Step 5: In the flushing process, on-line electrochemical monitoring is carried out by the external electrochemical workstation 9; in step 5, the on-line electrochemical monitoring includes one or more of open circuit potential, potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy.

[0062] Step 6: After the experiment is completed, the centrifugal pump 1, the temperature controller 7, and the oxygen concentration controller 10 are stopped in sequence.

[0063] Next, the application is further described in detail through examples.

[0064] Example 1: Simulating the erosion corrosion behavior of TA2 pure titanium under deep-sea low-temperature and low-oxygen environment

[0065] Test sample: TA2 pure titanium

[0066] Erosion medium: 3.5wt% NaCl aqueous solution.

[0067] Experimental parameter settings: temperature: 5℃; dissolved oxygen content: 2.0ppm; flow rate: 5m / s; attack angle: 90° (perpendicular impact); solid phase: 100 mesh SiO2 quartz sand about 2wt%.

[0068] Test process:

[0069] The prepared NaCl aqueous solution was injected into the solution tank 22, the working electrode 17 (test sample) was placed in the test sample clamp, the attack angle controller 23 was adjusted, and the target parameters were set through the flow rate controller 4, the temperature controller 7, and the oxygen concentration controller 10. First, start the temperature controller 7 to work the heating / cooling tube 20 to cool the medium to 5℃; at the same time, open the gas (N2) valve of the high-purity nitrogen gas cylinder, and bubble through the microporous aeration tube 21 to reduce and stabilize the dissolved oxygen content to 2.0ppm. After the environment is stabilized, start the centrifugal pump 1, adjust the frequency and select the appropriate variable diameter nozzle 16 to stabilize the flow rate at 5m / s. The working electrode 17, the reference electrode 18, and the counter electrode 19 are respectively connected to the Gamry electrochemical workstation 9 through the electrode lead, and the open circuit potential is immediately started to be continuously monitored for 24 hours.

[0070] Results: The evolution rule of the electrochemical parameters of TA2 pure titanium under simulated deep-sea erosion corrosion was successfully obtained, and it was found that the open circuit potential increased rapidly in the initial stage and then tended to be stable.

[0071] Example 2: Study on the influence of different flow rates on the erosion of TA2 pure titanium under low-temperature and low-oxygen conditions

[0072] Test sample: TA2 pure titanium.

[0073] Erosion medium: artificial seawater.

[0074] Experimental parameter settings: temperature: 10℃; dissolved oxygen content: 1.0ppm; flow rate: 2m / s, 5m / s, 10m / s; attack angle 90°, solid phase is 100 mesh SiO2 quartz sand about 1wt%.

[0075] Test process: repeat the procedure of example 1 at different flow rates, and perform potentiodynamic polarization curve test after open circuit potential is stable for 1h.

[0076] Results: by comparing the potentiodynamic polarization curve test of TA2 pure titanium at different flow rates, it is found that when the flow rate increases, the passivation current density of TA2 moves to the right, and the corrosion resistance decreases.

[0077] Comparative example 1:

[0078] Using traditional scouring equipment (without temperature control and oxygen control function), TA2 pure titanium is subjected to scouring experiment in 3.5wt% NaCl aqueous solution at room temperature and open system at a flow rate of 5m / s.

[0079] Results: the obtained corrosion current density is much higher than the data under the condition of example 2 of the present application, and cannot accurately reflect the performance of the material in the real deep sea low temperature and low oxygen environment.

[0080] Performance test shows that the device of the present application can accurately create a stable simulation environment, the obtained electrochemical data has good repeatability and high sensitivity, and can effectively distinguish the difference in scouring corrosion behavior of different processes under different environments.

[0081] The implementation results show that the present application can comprehensively simulate the deep sea low temperature, low oxygen and high flow rate environment, and can study the influence of different fluid parameters (attack angle, solid phase ratio) on material damage, realize real-time online monitoring of the scouring corrosion process, and solve the problem that the existing equipment cannot simulate the core characteristics of deep sea low temperature and low oxygen environment. The present application provides key experimental data for the selection and evaluation of deep sea equipment materials. The present application is flexible to operate, accurate in simulation environment and reliable in data, and is a kind of efficient experimental device and method suitable for deep sea material scientific research and engineering evaluation, which provides reliable technical means for reliability evaluation and life prediction of key materials of deep sea equipment.

Claims

1. A controllable temperature and oxygen flushing experimental device simulating deep sea environment, characterized in that, The device is provided with a flushing system, a temperature control system, a dissolved oxygen control system, an angle of attack adjustment system, an electrochemical test system, and a sample clamp on the sample as a working electrode, the sample clamp is installed on the clamp fixer of the angle of attack adjustment system, the electrochemical workstation of the electrochemical test system is connected with the working electrode, the reference electrode and the counter electrode through electrode leads respectively, the working electrode, the reference electrode and the counter electrode are located in the solution tank, the variable diameter nozzle of the flushing system corresponds to the working electrode, the thermocouple of the temperature control system and the dissolved oxygen sensor of the dissolved oxygen control system are arranged in the solution tank.

2. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 1, characterized in that, The device includes a centrifugal pump, a pressure gauge, a flow meter, a material propeller, a flow controller, a thermocouple, a valve, a temperature controller, a stirrer, an electrochemical workstation, an oxygen concentration controller, a gas source, a dissolved oxygen sensor, a valve, a filter, a sand collector, a variable diameter nozzle, a working electrode, a reference electrode, a counter electrode, a heating / cooling pipe, a microporous aeration pipe, a solution tank, an angle of attack controller, and the specific structure is as follows: The solution tank is provided with a thermocouple, a dissolved oxygen sensor, a filter, a sand collector, a variable diameter nozzle, a working electrode, a reference electrode, a counter electrode, a heating / cooling pipe, a microporous aeration pipe, and a stirring blade, wherein: the variable diameter nozzle has a reverse T-shaped tee structure, one end of the horizontal direction of the variable diameter nozzle is connected with the outlet of the centrifugal pump through a pipeline, a pressure gauge, a flow meter connected with a flow controller, and a valve are sequentially arranged on the pipeline connected with the outlet of the centrifugal pump, the other end of the horizontal direction of the variable diameter nozzle corresponds to the working electrode installed on the sample clamp through a nozzle, the upper end of the sand collector is provided with a speed-adjustable material propeller, and the vertical direction of the variable diameter nozzle corresponds to the sand collector, a valve for adjusting the sand into the variable diameter nozzle is arranged on the vertical direction, and the lower part of the inner cavity of the solution tank is horizontally provided with the microporous aeration pipe. The thermocouple and the heating / cooling pipe are connected with the temperature controller outside the solution tank through leads respectively, the dissolved oxygen sensor is connected with the input end of the oxygen concentration controller outside the solution tank through a lead, the output end of the oxygen concentration controller is connected with the gas source, the gas outlet of the gas source is connected with the microporous aeration pipe through a pipeline, the stirring blade is connected with the output end of the stirrer outside the solution tank through a vertical stirring shaft, the sample clamp of the working electrode is installed on the clamp fixer of the angle of attack adjustment system, and the angle of the working electrode is adjusted through the clamp fixer by the angle of attack controller outside the solution tank, and the working electrode, the reference electrode and the counter electrode are connected with the electrochemical workstation outside the solution tank through electrode leads respectively.

3. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The flushing system comprises a centrifugal pump, a variable-diameter nozzle connected to the outlet of the centrifugal pump, a sample holder for fixing the working electrode, a solution tank for storing the flushing medium, and a flow controller, wherein: the centrifugal pump is matched with the variable-diameter nozzle through frequency conversion control to realize flow rate regulation of 1-20 m / s; the variable-diameter nozzle has a replaceable structure and two or more outlet diameters, the variable-diameter nozzle is directly aimed at the surface of the working electrode, and the flushing medium is artificial seawater, NaCl aqueous solution or a simulated solution with specific components.

4. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The temperature control system comprises a heating / cooling pipe, a thermocouple and a temperature controller arranged in the solution tank, the temperature controller receives the thermocouple signal and controls the operation of the heating / cooling pipe, so that the temperature of the flushing medium can be adjusted in the range of 2-90℃, and the accuracy range is ±2℃; the refrigeration element is a semiconductor refrigerator or an external circulating cooling unit, and the heating element is a titanium metal heating rod or a quartz heating pipe.

5. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The dissolved oxygen control system comprises a gas source, a microporous aeration pipe, a dissolved oxygen sensor and an oxygen concentration controller, the oxygen concentration controller receives the dissolved oxygen sensor signal and controls the electromagnetic valve for gas input, so that the dissolved oxygen content in the flushing medium can be controlled in the range of 0.5 ppm to saturated oxygen; the gas source is a high-purity nitrogen cylinder or a high-purity argon cylinder, and the microporous aeration pipe is a titanium alloy microporous aeration head.

6. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The attack angle adjustment system comprises a holder fixer for fixing the sample holder, an attack angle controller and an angle sensor corresponding to the working electrode, and realizes stepless adjustment and locking of the attack angle between the surface of the working electrode and the flushing flow beam in the range of 0-90°; the attack angle controller receives the signal of the current attack angle of the working electrode collected by the angle sensor in real time, and sends a command to the worm gear mechanism, the holder fixer is driven through the worm gear mechanism, and the attack angle adjustment accuracy is better than ±1°.

7. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The electrochemical test system comprises a working electrode, a reference electrode, a counter electrode embedded in the sample holder and an electrochemical workstation, the working electrode, the reference electrode and the counter electrode are connected to the electrochemical workstation through electrode leads, and online electrochemical monitoring during the flushing process is realized.

8. The controllable temperature and oxygen flushing experimental device for simulating deep sea environment according to claim 2, characterized in that, The central control system is in communication connection with the controllers of the flushing system, the temperature control system, the dissolved oxygen control system and the attack angle adjustment system, and is used for setting and displaying the flow rate, the temperature, the dissolved oxygen content and the attack angle parameters.

9. A method for simulating deep-sea environment, controllable temperature and oxygen-flushed experiment using the device of any one of claims 1 to 8, characterized in that, The method comprises the following steps: Step 1: preparing the flushing medium and injecting it into the solution tank; Step 2: setting the target temperature, the target dissolved oxygen content, the target flow rate and the attack angle through the central control system; Step 3: starting the temperature controller and the oxygen concentration controller, and waiting for the temperature and the oxygen content of the flushing medium to stabilize to the set values; Step 4: starting the centrifugal pump, adjusting the target flow rate through the flow controller, and performing the flushing experiment; Step 5: performing online electrochemical monitoring through the external electrochemical workstation during the flushing process; Step 6: sequentially stopping the centrifugal pump, the temperature controller and the oxygen concentration controller after the experiment is completed.

10. The controllable temperature and oxygenated scouring test method simulating a deep sea environment according to claim 9, wherein, In step 3, the low-oxygen environment of deep sea is simulated by bubbling gas into the flushing medium until the dissolved oxygen content is reduced to ppm level; the low-temperature environment of deep sea is simulated by controlling the refrigeration element to reduce the medium temperature to 5-10℃; in step 4, the variable-diameter nozzle is replaced and the power of the centrifugal pump is adjusted so that the flow velocity of the flow beam emitted from the variable-diameter nozzle is stabilized at any value within the range of 1-20 m / s; in step 5, the online electrochemical monitoring includes one or two or more of open circuit potential, dynamic potential polarization, constant potential polarization and electrochemical impedance spectroscopy.

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