An evaporator for simulating multi-field coupling corrosion of salt vapor in a high temperature environment of the sea

Abstract

This invention provides an evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, relating to the field of material service performance testing. The evaporator includes a precision funnel feeding device, a mixing device, a high-temperature feeding pipeline, a double-layer aluminum silicate insulation layer, an evaporation unit, and a heated conveying pipeline. The precision funnel feeding device is used to quantitatively deliver dry salt powder; the mixing device mixes the salt powder with preheated carrier gas to form a gas-solid two-phase flow; the high-temperature feeding pipeline conveys the gas-solid two-phase flow to the evaporation unit; the evaporation unit contains an evaporation container and a preheated carrier gas introduction structure; the heated conveying pipeline uses zoned temperature control to form a positive temperature gradient; the double-layer aluminum silicate insulation layer wraps around key components to maintain temperature uniformity. This invention solves the problems of easy salt clogging, uneven deposition, and simulation distortion in existing technologies, enabling continuous and stable operation with high deposition efficiency, providing a high-fidelity simulation method for evaluating the thermal corrosion performance of nickel-based superalloys and other materials in high-temperature marine environments.

Description

Technical Field

[0001] This invention relates to the field of material service performance testing technology, specifically to an evaporator that simulates multi-field coupled corrosion of salt vapor in a high-temperature marine environment. Background Technology

[0002] Aero engines and gas turbines are core equipment in the aerospace and energy power fields, and their performance and reliability are directly related to flight safety and energy utilization efficiency. The hot-end components of these machines, such as turbine blades, guide vanes, and combustion chamber liners, operate in extremely harsh environments for extended periods. Taking aero engine turbine blades as an example, their operating temperatures reach 1000-1200℃, they bear enormous centrifugal and aerodynamic loads, and they face multiple failure threats, including high-temperature combustion gas oxidation and hot corrosion.

[0003] When an aircraft engine operates in a marine environment, the air it draws in contains a large amount of salt, primarily sodium chloride (NaCl), along with small amounts of magnesium chloride, sodium sulfate, and other sea salt components. These salts undergo complex physicochemical changes inside the engine: in the compressor section, the salt-containing air is compressed and heated to 300-600°C, causing some of the salt water droplets to evaporate and the salt to precipitate; in the combustion chamber section, the temperature rises sharply to 1500-2000°C, and the remaining salt evaporates completely into salt vapor; in the turbine section, the high-temperature combustion gases expand and cool, causing the salt vapor to condense and deposit on the relatively cooler blade surfaces (900-1200°C), forming a molten salt film. This molten salt film, along with elements such as sulfur and oxygen in the combustion gases, triggers severe high-temperature thermal corrosion, significantly accelerating material damage and failure.

[0004] Nickel-based superalloys are widely used in hot-end components such as turbine blades in aero-engines due to their excellent high-temperature strength, oxidation resistance, and hot corrosion resistance. Typical nickel-based superalloys include GH4169, GH4742, GH4720Li, GH4738, and GH4698. These alloys maintain good mechanical properties at high temperatures through complex alloying designs and heat treatment processes. However, in the high-temperature marine environment, nickel-based superalloys face particularly prominent hot corrosion problems. Studies have shown that hot corrosion rates can be tens or even hundreds of times higher than simple oxidation, seriously threatening the service safety and lifespan of components. Therefore, accurately evaluating the hot corrosion behavior of nickel-based superalloys in the high-temperature marine environment under laboratory conditions has significant engineering value and scientific significance for material selection, process optimization, and service life prediction.

[0005] In existing technologies, the main methods for simulating the effect of salt on the high-temperature performance of materials are as follows:

[0006] The first type is the static salt coating method. This method involves coating or spraying a salt solution onto the sample surface before testing. After drying, a solid salt crystal layer forms on the sample surface. The salt-coated sample is then placed in a high-temperature furnace for oxidation or thermal shock testing. This method is simple to operate, but it has significant drawbacks: First, the salt morphology does not match the real environment. In the real environment, salt is transported in the gas phase and then condenses to form a molten salt film, while the static coating method yields solid crystalline salt, whose contact state and reaction kinetics with the substrate are completely different from those of a molten salt film. Second, it cannot simulate the continuous input of salt. In a real engine, salt-containing air is continuously drawn in during operation, and salt is constantly deposited, while the static coating method can only simulate a single salt deposition. Third, the thickness and uniformity of the salt layer are difficult to control precisely, affecting the repeatability of the test results.

[0007] The second type is the room-temperature salt spray injection method. This method atomizes a salt solution at room temperature to form a salt spray aerosol, which is then directly sprayed into the high-temperature test area. This method attempts to simulate a continuous input of salt, but it encounters serious problems in practice: room-temperature salt spray droplets evaporate rapidly when they encounter high-temperature pipelines, and salt crystallizes prematurely on the inner wall of the pipeline, leading to pipeline blockage and nozzle failure; even if some salt spray can enter the high-temperature zone, the droplets violently splash when they hit the high-temperature surface, resulting in low salt deposition efficiency and uneven distribution; in addition, the deposition of crystalline salt on the inner wall of the pipeline can also cause system pressure fluctuations, affecting the stability of the experiment.

[0008] The third type is the high-temperature molten salt coating method. This method involves pre-melting the salt and then coating the molten salt onto the surface of a preheated sample to form a molten salt film, followed by high-temperature testing. While this method simulates the morphology of a molten salt film to some extent, it still has drawbacks: firstly, it is difficult to control the thickness and uniformity of the molten salt film during the coating process; secondly, it cannot simulate the condensation and deposition process of salt vapor on the surface; and thirdly, it cannot achieve continuous replenishment of salt, and for long-term tests, the molten salt film will be completely consumed due to evaporation and reaction.

[0009] In summary, existing technologies struggle to achieve the vapor-phase transport and controlled deposition of salts in real high-temperature combustion gas environments, failing to accurately reproduce the entire salt evolution process experienced by aero-engine turbine blades in high-temperature marine environments. This technological gap restricts the accuracy and depth of research on the hot corrosion behavior of nickel-based superalloys and also affects the development efficiency of novel heat-resistant corrosion-resistant materials and protective coatings. Therefore, developing a system capable of precisely and stably injecting salts in vapor form into high-temperature combustion gas environments is of great significance for advancing research on the hot corrosion of materials. Summary of the Invention

[0010] Technical problems to be solved

[0011] To address the shortcomings of existing technologies, this invention provides an evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, solving the following problems: how to accurately reproduce the complete physicochemical process of salt evaporation-gas transport-surface condensation experienced by aero-engine turbine blades in a high-temperature marine environment under laboratory conditions; how to prevent premature crystallization and deposition of salt in the transport system to ensure long-term stable operation of the system; how to achieve precise control of salt vapor concentration, deposition rate, and deposition location to improve the repeatability and reliability of the experiment; and how to organically integrate the salt vapor injection system with existing gas corrosion testing equipment to achieve high-fidelity simulation of the thermo-mechanical-salt multi-field coupled environment.

[0012] Technical solution

[0013] To achieve the above objectives, the present invention provides the following technical solution: an evaporator simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, comprising: a precision funnel feeding device for storing and quantitatively conveying dried salt powder; a mixing device connected to the outlet of the precision funnel feeding device for initially mixing the salt powder with a carrier gas to form a gas-solid two-phase flow; a high-temperature feeding pipe, one end of which is connected to the outlet of the mixing device, and the other end of which is connected to the inlet of the evaporation device for conveying the gas-solid two-phase flow to the evaporation device; an evaporation device for receiving the salt powder and heating it to a molten evaporation state to generate salt vapor; a heated conveying pipe, one end of which is connected to the vapor outlet of the evaporation device, and the other end of which is connected to an external test chamber for conveying the salt vapor to the test area at a high temperature; and a double-layer aluminum silicate insulation layer wrapped around the high-temperature feeding pipe, the evaporation device, and the heated conveying pipe to reduce heat loss and maintain temperature uniformity.

[0014] Preferably, the precision funnel feeding device includes: a moisture-proof hopper with an internal heating and insulation layer and a desiccant to keep the salt powder dry; a micro-screw feeder installed at the bottom of the moisture-proof hopper for quantitatively conveying the salt powder at a rate of 0.01-5 g / min; and an anti-bridging vibrator connected to the moisture-proof hopper to prevent the salt powder from bridging and clogging inside the hopper. The mixing device includes: a mixing chamber with an internal static mixing element; and a carrier gas inlet located on the side wall of the mixing chamber for introducing preheated dry carrier gas to above 600°C. The mixing chamber uniformly mixes the salt powder with the carrier gas. The gas-solid two-phase flow is formed; the high-temperature feeding pipeline has a double-layer structure, with the inner layer being a high-temperature and corrosion-resistant material and the outer layer being a double-layer aluminum silicate insulation layer, and multiple temperature monitoring points are set along the length of the pipeline; the evaporation device includes: an evaporation chamber, made of a high-temperature resistant and molten salt corrosion-resistant material, with an externally wrapped electric heating element; an evaporation container, located inside the evaporation chamber, used to hold and heat the salt raw material to a molten state; and a preheating carrier gas introduction structure, located inside the evaporation chamber and adjacent to the liquid surface of the evaporation container, used to introduce the preheating carrier gas in a laminar flow form close to the molten salt surface, stripping and carrying away the evaporated salt.

[0015] Preferably, the evaporation container has a shallow dish-shaped structure and is made of platinum-rhodium alloy or tantalum-tungsten alloy; a weight sensor is provided at the bottom of the evaporation container to monitor the change in the quality of the salt raw material in real time; the preheating carrier gas introduction structure is a slit nozzle or a micro-orifice array nozzle, the outlet direction of which is parallel to or at an acute angle to the molten salt surface, and the carrier gas flow rate is 1-10 L / min.

[0016] Preferably, the heat tracing pipeline is divided into multiple independent temperature control sections along its length. The temperature control setpoint of each temperature control section increases along the salt vapor flow direction to form a positive temperature gradient and prevent salt vapor from condensing and depositing. An injection nozzle is provided at the end of the heat tracing pipeline, and a concentric sleeve is provided around the injection nozzle to introduce clean gas to form an annular sheath flow and constrain the salt vapor stream.

[0017] Preferably, it also includes a precision control and monitoring unit, which includes: a multi-level temperature control system for independently controlling the temperature of each temperature zone of the evaporation device and the heat tracing pipeline; a mass flow control system for controlling the carrier gas flow rate and the sheath gas flow rate; and process monitoring sensors, including a weight sensor installed at the bottom of the evaporation container, a differential pressure sensor installed at key points of the heat tracing pipeline, and a particle size monitoring probe installed at the outlet of the injection nozzle.

[0018] Preferably, it also includes an auxiliary support unit, which includes: an automatic purging system connected to a drying carrier gas source for high-temperature purging of the evaporation device and the heat tracing pipeline; and a safety interlock system connected to monitoring sensor signals for automatically triggering an alarm and performing a safe shutdown in abnormal conditions.

[0019] A method for conducting high-temperature salt spray corrosion testing of nickel-based superalloys using an evaporator, characterized by comprising the following steps:

[0020] Sp1: System preheating, heating the evaporator and heat tracing pipeline to the preset temperature;

[0021] Sp2: Introduce preheated carrier gas to establish a stable carrier gas flow field;

[0022] Sp3: Start the precision funnel feeding device to feed the dry salt powder into the mixing device in a measured amount. After mixing with the carrier gas, it enters the evaporation device through the high-temperature feeding pipeline.

[0023] Sp4: Salt powder melts and evaporates in the evaporation device, and the resulting salt vapor is stripped off by the carrier gas that is in close contact with the surface of the molten salt;

[0024] Sp5: Salt vapor is transported to the test chamber via a heated pipeline under high-temperature tracing throughout the process and injected into the high-temperature gas flow;

[0025] Sp6: Salt vapor condenses and deposits on the surface of a nickel-based superalloy sample to form a molten salt film, which is then used for hot corrosion testing.

[0026] Sp7: Real-time monitoring of temperature, flow rate, mass changes, and differential pressure; dynamic parameter adjustment.

[0027] Sp8: After the test is completed, stop feeding and perform high-temperature purging to remove residual salt.

[0028] Preferably, the preset temperature in Sp1 is: 800-950℃ inside the evaporator, and the temperature of each temperature zone in the heat tracing pipeline is 20-150℃ higher than the temperature of the evaporator and increases along the flow direction; the carrier gas in Sp2 is nitrogen or dry air, with a flow rate of 1-10L / min and a preheating temperature ≥600℃; the salt powder in Sp3 is one or more of sodium chloride, potassium chloride, and sodium sulfate, with a feeding rate of 0.01-5g / min; the high-temperature gas flow temperature in Sp5 is 800-1600℃, and the nickel-based high-temperature alloy sample is selected from one or more of GH4169, GH4742, GH4720Li, GH4738, and GH4698, with the sample surface temperature controlled at 900-1200℃; the dynamic adjustment in Sp7 includes: adjusting the evaporation temperature according to the deviation between the mass change rate of the evaporator and the feeding rate, adjusting the carrier gas flow rate or triggering purging according to the pipeline pressure difference, and adjusting the mixing chamber temperature according to particle size monitoring data.

[0029] Beneficial effects

[0030] This invention provides an evaporator that simulates multi-field coupled corrosion of salt vapor in a high-temperature marine environment. It has the following beneficial effects:

[0031] 1. Revolutionary Improvement in Simulation Fidelity. This invention's evaporator, for the first time in the laboratory, realizes the transport and deposition of salts in gaseous form within a high-temperature combustion gas environment, accurately replicating the phase transition process of salts during actual service in aero-engines: evaporation-gas phase transport-condensation. This technological breakthrough enables laboratory tests to realistically reflect the thermal corrosion behavior of materials in high-temperature marine environments, achieving a qualitative leap in the mechanistic authenticity and data reliability of the test results. Tests conducted using this invention's evaporator show corrosion kinetic curves, corrosion product morphology, and compositional distribution that highly match those of the engine blades after actual service, verifying the simulation's realism.

[0032] 2. Solving the clogging problem. The evaporator of this invention fundamentally prevents salt condensation and deposition during evaporation and transport by establishing a strict positive temperature gradient field of "evaporation chamber < mixing chamber < transport pipeline" and a laminar flow carrier gas stripping mechanism closely adhering to the evaporation surface. Experiments show that the evaporator using this invention can operate continuously and stably for over 500 hours without significant deposition, with pipeline pressure differential fluctuations of less than 5%, greatly improving system reliability and service life. In comparative tests, similar devices without a positive temperature gradient showed a significant increase in pressure differential after 2 hours of operation and complete clogging after 4 hours.

[0033] 3. Excellent controllability and uniformity of deposition. Salt vapor condenses on the sample surface to form a uniform and continuous initial salt film, avoiding the rebound and splashing problems caused by solid particle impact. Combined with sheath flow technology, the salt deposition area can be precisely controlled, with a deposition efficiency of over 90% (determined by the mass balance method). The coefficient of variation for deposition uniformity is less than 8%, significantly better than existing technologies. Microscopic observation of the deposited salt film shows a uniform thickness distribution, with no localized excessive thickness or gaps.

[0034] 4. Precisely adjustable parameters, high scientific research value. The evaporator of this invention can independently and precisely control key parameters such as salt evaporation temperature, carrier gas flow rate, salt vapor concentration, and injection position, facilitating systematic research on the individual and coupled effects of factors such as temperature, salt morphology, and concentration on material corrosion behavior. By adjusting the feed rate and carrier gas flow rate, the salt vapor concentration in the fuel gas can be controlled within the range of 0.1-20 ppm, accurately simulating a wide range of operating conditions from clean marine environments to high-salt-fog environments.

[0035] 5. This invention expands the research depth of nickel-based superalloys. Applying the evaporator of this invention to test typical nickel-based superalloys such as GH4169 and GH4742 yields key data such as salt deposition rate, molten salt film stability, corrosion kinetic curves, and corrosion product evolution patterns, providing an experimental basis for establishing a mechanism-based hot corrosion life prediction model. The study found that the corrosion rates of different alloys at the same salt vapor concentration can differ by more than three times; this system can accurately distinguish these differences, providing a reliable means for alloy screening.

[0036] 6. Economical operation and convenient maintenance. The modular design makes it easy to replace the key component, the evaporator container, which is made of platinum-rhodium alloy and has a design life of over 500 hours. The efficient evaporation and transport process reduces salt waste and pipeline cleaning frequency. Combined with the automatic purging function, the maintenance cycle is extended to over 100 hours, significantly reducing long-term operating costs. Preliminary estimates indicate that the operating cost of the evaporator of this invention is only 60% of that of traditional methods. Attached Figure Description

[0037] Figure 1 This is a side sectional view of the present invention;

[0038] Figure 2 This is a front view of the present invention;

[0039] Figure 3 This is a schematic diagram of the mixing device of the present invention;

[0040] Figure 4 This is a side sectional view of the mixing device of the present invention;

[0041] Figure 5 This is a schematic diagram of the precision funnel feeding device of the present invention;

[0042] Figure 6 This is a schematic diagram of the evaporation apparatus of the present invention;

[0043] Figure 7 This is a schematic diagram of the heat tracing and conveying pipeline of the present invention;

[0044] Figure 8 This is a cloud diagram of the test system method of the present invention;

[0045] Figure 9 This is a system architecture diagram of the present invention;

[0046] Figure 10 This is a flowchart of the process of the present invention.

[0047] The components include: 1. Precision funnel feeding device; 11. Moisture-proof hopper; 12. Micro-screw feeder; 13. Anti-bridging vibrator; 2. Mixing device; 21. Mixing chamber; 22. Carrier gas inlet; 3. High-temperature feeding pipeline; 4. Double-layer aluminum silicate insulation layer; 5. Evaporation device; 51. Evaporation chamber; 52. Evaporation container; 53. Preheating carrier gas introduction structure; 54. Weight sensor; 6. Heated conveying pipeline; 61. Injection nozzle; 62. Concentric sleeve. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0050] like Figures 1 to 10 As shown, an evaporator simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment is presented. The evaporator adopts a modular design and achieves stable transport and controllable deposition of salt in vapor form by establishing a strict positive temperature gradient and a unique carrier gas stripping mechanism.

[0051] The present invention provides an evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, comprising: a precision funnel feeding device 1, a mixing device 2, a high-temperature feeding pipeline 3, a double-layer aluminum silicate insulation layer 4, an evaporation device 5, and a heat-traced conveying pipeline 6.

[0052] The precision funnel feeding device 1 is used for storing and quantitatively conveying dry salt powder. Its specific structure includes: a moisture-proof hopper 11, with an internal heating and insulation layer at 80-100℃ and a desiccant to keep the salt powder dry and prevent moisture absorption and clumping; a micro-screw feeder 12, installed at the bottom of the moisture-proof hopper 11, driven by a precision servo motor, capable of stepless speed regulation within the range of 0.01-5g / min, with a feeding accuracy of ±1%; and an anti-bridging vibrator 13, connected to the moisture-proof hopper 11, which is electromagnetic or pneumatic, with adjustable frequency, used to prevent salt powder from bridging and clogging within the hopper, ensuring continuous and stable feeding.

[0053] The mixing device 2 is connected to the outlet of the precision funnel feeding device 1 and is used to initially mix the salt powder with the carrier gas to form a gas-solid two-phase flow. The mixing device 2 includes a mixing chamber 21 and a carrier gas inlet 22. The mixing chamber 21 is equipped with a static mixing element to promote uniform mixing of the salt powder and the carrier gas. The carrier gas inlet 22 is located on the side wall of the mixing chamber 21 and is connected to an external dry carrier gas source. The carrier gas is usually high-purity nitrogen or dry air, which is preheated to above 600°C by a preheater before being introduced. The preheating temperature can be adjusted as needed. The carrier gas flow rate is controlled by a high-precision mass flow controller, ranging from 1-10 L / min. After the salt powder falls into the mixing chamber 21, it is impacted and dispersed by the high-speed carrier gas to form a uniform gas-solid two-phase flow.

[0054] The high-temperature feeding pipe 3 is connected at one end to the outlet of the mixing device 2 and at the other end to the inlet of the evaporation device 5, and is used to transport the gas-solid two-phase flow to the evaporation device 5. The high-temperature feeding pipe 3 has a double-layer structure. The inner layer is made of high-temperature and corrosion-resistant material, and the outer layer is wrapped with a double-layer aluminum silicate insulation layer 4 to reduce heat loss and maintain the temperature inside the pipe. Multiple thermocouples with temperature monitoring points are installed along the length of the pipe to monitor the temperature distribution inside the pipe in real time, ensuring that the salt powder does not absorb moisture or react prematurely during transportation.

[0055] The evaporation device 5 is used to receive salt powder and heat it to a molten evaporation state to generate salt vapor. The evaporation device 5 includes: an evaporation chamber 51, an evaporation container 52, a preheating carrier gas introduction structure 53, and a weight sensor 54.

[0056] The evaporation chamber 51 is made of high-temperature resistant and molten salt corrosion resistant materials, with a platinum-rhodium alloy lining or 99.7% high-purity alumina ceramic, and an externally wound electric heating element. The heating power can be designed as needed, and the internal temperature can be precisely controlled within the range of 800℃ to 950℃ with a temperature control accuracy of ±1℃. The evaporation chamber 51 has a cylindrical or square structure, and the top is equipped with an openable sealing cover for easy installation and removal of the evaporation container 52.

[0057] An evaporation container 52 is located inside the evaporation chamber 51 and is used to hold and heat the salt raw material to a molten state. The evaporation container 52 is preferably made of platinum-rhodium alloy or tantalum-tungsten alloy, as these materials have good corrosion resistance to molten salt at high temperatures. The evaporation container 52 is preferably shallow dish-shaped to increase the evaporation surface area and improve evaporation efficiency. Its typical dimensions are a diameter of 80 mm, a depth of 15 mm, and a wall thickness of 2 mm. The bottom of the evaporation container 52 is connected to a weight sensor 54 via a ceramic support rod. The weight sensor 54 has a measuring range of 0-500 g and an accuracy of ±0.01 g, and is used to monitor the mass change of the salt raw material inside the evaporation container in real time, thereby calculating the evaporation rate and the amount of remaining salt.

[0058] The preheating carrier gas introduction structure 53 is located inside the evaporation chamber 51, immediately above the liquid surface of the evaporation container 52. Specifically, it is a slit nozzle or a micro-orifice array nozzle, with its outlet direction parallel to or at an acute angle to the molten salt surface. This structure introduces preheated, dry carrier gas in a laminar flow pattern, closely adhering to the molten salt surface, creating an "air knife" effect to promptly peel away and remove the evaporated salt. The preheating carrier gas introduction structure 53 is connected to an external carrier gas source via a pipe. The carrier gas flow rate is controlled by an independent mass flow controller, typically 1-10 L / min, with a preheating temperature ≥600℃. This design ensures that the carrier gas can uniformly cover the entire molten salt surface, preventing localized oversaturation that could cause salt condensation near the liquid surface.

[0059] One end of the heat-traced transport pipe 6 is connected to the steam outlet of the evaporation device 5, and the other end is used to connect to the external test chamber, for transporting salt vapor to the test area at a high temperature. The heat-traced transport pipe 6 has a multi-layer composite structure: the inner layer is made of high-temperature and corrosion-resistant material, the middle layer is a heating element, and the outer layer is a double-layer aluminum silicate insulation layer 4. The heat-traced transport pipe 6 is divided into multiple independent temperature control sections along its length, with each temperature zone consisting of 0.5m sections. Each temperature zone is equipped with an independent heating element and thermocouple. The temperature control setpoint increases along the direction of salt vapor flow, forming a strict positive temperature gradient of evaporation chamber 51 temperature < mixing chamber temperature < transport pipe temperature, preventing salt vapor from condensing and depositing during transport due to temperature reduction. Typical temperature zone settings: first temperature zone 950℃, second temperature zone 970℃, third temperature zone 990℃, and fourth temperature zone 1000℃.

[0060] The end of the heat tracing and delivery pipeline 6 is equipped with an injection nozzle 61, which is used to inject salt vapor into the high-temperature gas flow in the test chamber. The injection nozzle 61 is protected by a water-cooled or air-cooled jacket to prevent the nozzle from overheating. A concentric sleeve 62 is set around the nozzle, which is connected to an independent clean gas source to form an annular sheath flow around the injection nozzle 61, constraining the salt vapor beam and concentrating it on the sample surface, while preventing the salt vapor from contaminating the inner wall of the test chamber.

[0061] The evaporator of this invention also includes a precision control and monitoring unit, which comprises a multi-stage temperature control system, a mass flow control system, and process monitoring sensors. The multi-stage temperature control system includes multiple high-precision thermocouples and a PID temperature controller, which independently control the temperature of each temperature zone in the evaporation unit 5 and the heat tracing pipeline 6. The mass flow control system includes a high-precision mass flow controller for adjusting the carrier gas flow rate and the sheath gas flow rate. The process monitoring sensors include a weight sensor 54 located at the bottom of the evaporation container 52, a differential pressure sensor located at key points in the heat tracing pipeline 6, and an optical or laser particle size monitoring probe located at the outlet of the injection nozzle 61.

[0062] The evaporator of this invention also includes an auxiliary support unit, which comprises an automatic purging system and a safety interlock system. The automatic purging system is connected to the drying carrier gas source and can automatically switch to a high-flow mode before system startup, after shutdown, or when an abnormality is detected. This mode performs high-temperature purging of the evaporation unit 5 and the heated conveying pipeline 6 to remove residual salt. The safety interlock system is connected to monitoring sensor signals. When it detects a disruption of the temperature gradient, an abnormal increase in pressure difference, or an abnormal increase in the mass of the evaporation container 52, indicating that salt has not been effectively evaporated, it automatically triggers an alarm and executes a safety shutdown procedure, stopping the feed, increasing the carrier gas purging, and cutting off the heating power supply.

[0063] The present invention also provides a method for conducting high-temperature salt spray corrosion testing of nickel-based superalloys using the above-mentioned evaporator, comprising the following steps:

[0064] Sp1: System preheating stage. Start the heaters in each section to heat the evaporation chamber 51 of the evaporator 5 and each temperature zone of the heat tracing pipeline 6 to the preset temperature, establishing a strict temperature gradient. The preset temperature range is: evaporation chamber 51 temperature 800-950℃, the first temperature zone of the heat tracing pipeline 6 is 50-100℃ higher than the evaporation chamber temperature, and subsequent temperature zones increase by 20-50℃ sequentially to ensure a positive temperature gradient.

[0065] Sp2: Carrier gas introduction stage. Preheated dry carrier gas is introduced to establish a stable carrier gas flow field. High-purity nitrogen or dry air is preferred as the carrier gas, with a total flow rate of 1-10 L / min. The carrier gas passing through mixing device 2 is used to transport salt powder, while the carrier gas passing through preheated carrier gas introduction structure 53 is used to strip salt vapor. The carrier gas preheating temperature is ≥600℃.

[0066] Sp3: Salt Conveying and Evaporation Stage. The micro-screw feeder 12 of the precision funnel feeding device 1 is activated, conveying the dry salt powder to the mixing device 2 at a constant rate of 0.01-5 g / min. After mixing with the carrier gas, the powder enters the evaporation container 52 of the evaporation device 5 through the high-temperature feeding pipe 3. The salt powder is heated to a molten state in the evaporation container 52 and then evaporates. The temperature of the molten salt in the evaporation chamber 51 is controlled at 50-100°C above the melting point of the salt. For sodium chloride with a melting point of 801°C, the preferred evaporation temperature is 860-880°C; for mixed sea salt with a melting point of approximately 650°C, the preferred evaporation temperature is 700-750°C. The generated salt vapor is stripped and carried away by the preheated carrier gas flowing close to the surface of the molten salt.

[0067] Sp4: Salt vapor transport stage. Salt vapor enters the heated transport pipeline 6 from the outlet of evaporation chamber 51 and is transported to the test chamber in a gaseous state under high-temperature heating throughout the process. During this process, each temperature control zone maintains a set positive temperature gradient to ensure that the salt vapor is always in a superheated state and will not condense and deposit. The temperature inside the heated transport pipeline 6 is usually maintained at 950-1050℃.

[0068] Sp5: Injection and Deposition Stage. Salt vapor is injected into the high-temperature gas flow within the test chamber through injection nozzle 61. The gas flow within the test chamber is generated by a burner and operates at a temperature of 800-1600℃, with the flow rate adjustable as needed. The nickel-based superalloy sample is installed within the test chamber, and its surface temperature is monitored using an infrared thermometer or thermocouple, controlled at 900-1200℃. Salt vapor condenses and deposits on the relatively cool sample surface, forming a uniform molten salt film, initiating the hot corrosion process.

[0069] Sp6: Process Monitoring Stage. Real-time monitoring of temperature, carrier gas flow rate, mass change of evaporator 52, and pipeline pressure differential in each zone, dynamically adjusting operating parameters based on monitoring data. Specific adjustment strategies include: adjusting the temperature of evaporation chamber 51 based on the deviation between the mass change rate of evaporator 52 and the feed rate to ensure a balance between the evaporation rate and the feed rate; ideally, the mass change rate should equal the feed rate; adjusting the carrier gas flow rate or triggering an automatic purging program based on pipeline pressure differential changes; automatically increasing the carrier gas flow rate or initiating temporary purging when the pressure differential exceeds a set threshold to prevent blockage; and adjusting the mixing chamber temperature based on particle size monitoring data at the injection nozzle 61 outlet to ensure that salt is output in the expected form as vapor or submicron particles.

[0070] Sp7: Test Completion and Purging Phase. After the preset test time is reached, stop feeding salt powder, maintain carrier gas flow and system high temperature, and run the automatic purging program to remove residual salt. The purging program uses high-flow-rate dry carrier gas, and the purging time is 10-30 minutes. During the purging process, maintain the system temperature at no less than 80% of the operating temperature to ensure that residual salt is fully discharged and to prevent crystallization and blockage of pipelines after cooling. Specific Implementation Example 2:

[0072] like Figures 1 to 10 As shown, the following is the specific implementation process for evaporator testing:

[0073] Hot corrosion test of pure sodium chloride vapor on GH4169 alloy:

[0074] A specific implementation procedure for pure sodium chloride vapor corrosion testing of GH4169 nickel-based superalloy:

[0075] Preliminary preparation and parameter setting: Dry pure sodium chloride powder is loaded into the moisture-proof hopper 11 of the precision funnel feeding device 1. The temperature inside the evaporation chamber 51 is set to 880℃, slightly higher than the melting point of sodium chloride (801℃) to ensure efficient evaporation. The temperature zones of the heated conveying pipeline 6 are set as positive temperature gradients: zone 1 950℃, zone 2 970℃, zone 3 990℃, and zone 4 1000℃.

[0076] Feeding and evaporation process: High-purity nitrogen gas, preheated to above 600℃, is introduced as the carrier gas, with a flow rate set to 5L / min by a mass flow controller. The micro-screw feeder 12 is started, feeding sodium chloride powder into the mixing device 2 at a constant rate of 0.5g / min. The salt powder melts in the evaporation container 52 and is rapidly stripped away by the laminar flow "air knife" blown out by the preheated carrier gas introduction structure 53.

[0077] Deposition and testing: Under strict positive temperature gradient protection, salt vapor is transported to the test chamber through the heated pipeline 6, and finally condenses and deposits on the surface of the GH4169 alloy sample with the surface temperature controlled at 900℃, forming a continuous molten salt film, thus initiating the high-temperature hot corrosion test.

[0078] An implementation process for mixed sea salt corrosion testing of GH4720Li nickel-based superalloy, relying on closed-loop dynamic adjustment of the system:

[0079] Preliminary preparations and parameter settings: The hopper is filled with sea salt powder, a mixture of sodium chloride and sodium sulfate. Since the melting point of the mixed sea salt is relatively low, the evaporation temperature of evaporation chamber 51 is set to 750℃. The temperature gradient of the heat tracing conveying pipeline 6 is set to an increasing gradient from 800℃ to 900℃.

[0080] Dynamic adjustment and control: The feeding rate of the micro-screw feeder 12 is set to 1.0 g / min, and the total carrier gas flow rate is set to 8 L / min. During operation, the weight sensor 54 at the bottom of the evaporation container 52 monitors the mass change of the salt raw material in real time. When the process monitoring unit detects that the mass decrease rate of the evaporation rate is lower than 1.0 g / min, the multi-stage temperature control system will automatically fine-tune the temperature of the evaporation chamber 51 to 770℃ to ensure that the evaporation rate and the feeding rate reach a dynamic balance and prevent excessive accumulation of salt in the container.

[0081] Precise sheath flow confinement: When the carrier gas carrying salt vapor runs to the injection nozzle 61, clean gas is introduced through the outer concentric sleeve 62 to form an annular sheath flow, which confines the salt vapor beam to prevent it from spreading outwards, so that it is efficiently concentrated and deposited on the surface of the GH4720Li alloy sample with the surface temperature set at 1050℃. Specific Implementation Example 3:

[0083] like Figures 1 to 10 As shown, based on the content of the above specific embodiments, the working principle of the present invention is further disclosed:

[0084] This evaporator overcomes the technical bottlenecks of salt crystallization blockage and uneven deposition in existing technologies. By quantitatively converting solid salt powder into gaseous salt vapor, and then re-condensing it on the sample surface after non-condensing transport, it accurately replicates the real-world service physicochemical process of "evaporation-gas phase transport-condensation" in aero-engines operating in high-temperature marine environments. Its complete working principle can be summarized into the following five key stages according to the process flow:

[0085] Moisture-proof storage and quantitative feeding: The dried salt powder is stored in a moisture-proof hopper 11 with a heating and insulation layer and a desiccant. With the assistance of an anti-bridging vibrator 13, a micro screw feeder 12 precisely and continuously feeds the salt powder into the mixing device 2.

[0086] Gas-solid mixing and insulated conveying: Inside the mixing chamber 21, salt powder collides and mixes with preheated high-temperature dry carrier gas at ≥600℃ to form a uniformly dispersed gas-solid two-phase flow. This two-phase flow enters the high-temperature environment through a high-temperature feeding pipe 3 wrapped with a double-layer aluminum silicate insulation layer 4 to prevent moisture absorption or premature reaction.

[0087] Melting and Evaporation with Airflow Stripping: Salt powder falls into the high-temperature and corrosion-resistant evaporation container 52 inside the evaporation device 5, where it rapidly absorbs heat, melts, and generates salt vapor. At this time, the preheated carrier gas introduction structure 53, located above the liquid surface, blows out laminar carrier gas in a parallel or acute-angle direction, forming an "air knife" effect. This gas adheres closely to the liquid surface, rapidly stripping away and carrying away the newly generated salt vapor, thus preventing localized supersaturation of vapor pressure and crystallization.

[0088] Forward gradient transport and constrained deposition: The carrier gas carrying salt vapor enters the heated transport pipeline 6. This pipeline is divided into multiple independent temperature control zones along its length, implementing a forward increasing temperature gradient control from "evaporation chamber 51 < mixing chamber < transport pipeline". This design ensures that the salt vapor remains superheated throughout the transport process, fundamentally preventing condensation and blockage along the pipe walls. When it reaches the final injection nozzle 61, the salt vapor beam is precisely injected into the test chamber by the constraint of the gaseous annular sheath flow ejected from the concentric sleeve 62. When the salt vapor encounters the relatively cool high-temperature alloy sample (900-1200℃), it condenses and deposits on its surface, forming a uniform and continuous molten salt film, which in turn triggers a severe multi-field coupled thermal corrosion reaction.

[0089] Closed-loop monitoring and self-cleaning purging: The entire equipment operation is monitored in real time by a multi-level control system and sensors, which provide dynamic feedback and fine-tune the feeding, temperature, and flow parameters. After the test or in case of abnormal system pressure difference, the automatic purging system will use high-flow carrier gas to perform high-temperature self-cleaning purging to remove residual salts from the pipeline and ensure the long-term safe operation of the equipment. Specific Implementation Example 4:

[0091] like Figures 1 to 10 As shown in the above specific embodiments, the following content is further disclosed:

[0092] The present invention provides an experimental method for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, the specific implementation of which is as follows:

[0093] Sp1. System preheating and thermal equilibrium establishment stage:

[0094] First, the multi-stage temperature control system is activated to independently preheat the evaporator 5, the heated conveying pipeline 6, and the mixing device 2 in separate zones. The temperature inside the evaporator 5 is heated to a first preset range of 800°C to 950°C. Simultaneously, the heating elements in each temperature zone of the heated conveying pipeline 6 are activated, setting the temperature of each zone to be 20°C to 150°C higher than the temperature of the evaporator 5, and ensuring that the temperature of each zone increases in a stepped manner along the direction of salt vapor flow. Through this positive temperature gradient design, an anti-condensation thermal boundary layer is established on the inner wall of the pipeline, providing a thermodynamic basis for the stable transport of subsequent salt vapor.

[0095] Sp2. Stable carrier gas field construction stage:

[0096] Preheated dry carrier gas, selected from nitrogen or dry air, is introduced into the system. The carrier gas flow rate is precisely stabilized between 1 liter per minute and 10 liters per minute using a mass flow control system. The carrier gas is preheated to above 600 degrees Celsius before entering the mixing device 2 to prevent thermal shock to the subsequent evaporation process from the cold airflow. The carrier gas operates in two paths: one path enters the mixing device 2 as the conveying power, and the other path enters the preheated carrier gas inlet structure 53 to strip salt vapor, thereby establishing a stable pressure field and flow field throughout the system.

[0097] Sp3. Quantitative feeding and gas-solid mixing stage:

[0098] Based on the corrosion intensity requirements set in the experiment, the precision funnel feeding device 1 is activated. Continuous micro-vibration of the anti-bridging vibrator 13 ensures the smooth flow of dry salt powder within the moisture-proof hopper 11. A micro-screw feeder 12 feeds the salt powder into the mixing chamber 21 at a constant rate of 0.01 g / min to 5 g / min. Within the mixing chamber 21, the salt powder undergoes thorough collision and mixing with the high-temperature carrier gas, forming a uniformly sized gas-solid two-phase flow under the mechanical disturbance of the static mixing elements. This two-phase flow is then transported to the evaporation zone via a double-layered high-temperature feeding pipe 3.

[0099] Sp4. Phase transition and air knife stripping stage:

[0100] The salt powder entering the evaporation container 52 rapidly absorbs radiant and convective heat under high temperature conditions, transforming into a molten liquid. The evaporation temperature is dynamically adjusted according to the different salt powder compositions; when using sodium chloride, 860°C to 880°C is preferred; when using mixed sea salt, 700°C to 750°C is preferred. The laminar gas jet generated by the preheating carrier gas introduction structure 53 passes close to the molten liquid surface at high speed, utilizing the air knife effect to rapidly strip the newly generated saturated salt vapor from the liquid surface and carry it into the gas phase fluid, significantly improving evaporation efficiency by reducing the local partial pressure at the liquid surface.

[0101] Sp5. Superheated transport and sheath confinement stage:

[0102] Carrier gas carrying salt vapor enters the heated delivery pipe 6. Maintaining a positive temperature gradient throughout the entire process keeps the salt vapor in a superheated state, eliminating the risk of condensation and crystallization along the way. As the salt vapor flows through the injection nozzle 61, clean sheath gas is introduced to the periphery through the concentric sleeve 62. The sheath gas forms an annular gaseous protective layer at the nozzle outlet, using fluid constraint to limit the radial diffusion of the salt vapor stream, allowing it to be precisely injected into the high-temperature gas flow with a preset temperature of 800°C to 1600°C, simulating the actual service conditions of an aero-engine.

[0103] Sp6. Multi-field coupled corrosion deposition stage:

[0104] The confined salt vapor beam arrives at the surface of the nickel-based superalloy sample along with the combustion gas flow. The sample is selected from one or more of the nickel-based superalloys GH4169, GH4742, GH4720Li, GH4738, and GH4698. The sample surface temperature is precisely maintained between 900°C and 1200°C by adjusting the external cooling airflow. At this point, the gaseous salt vapor undergoes physical condensation on the relatively cool sample surface, forming a uniform molten salt film of controllable thickness. Under the multi-field coupling effect of high temperature, high-speed combustion gas erosion, and preset stress load, this salt film induces a deep hot corrosion reaction on the alloy matrix.

[0105] Sp7. Parameter Dynamic Monitoring and Feedback Adjustment Stage:

[0106] Throughout the testing process, the control center monitored sensor data at each key node in real time. Weight sensor 54 monitored the real-time consumption rate of the salt raw material and compared it with the feeding instructions from the micro-screw feeder 12. If a deviation occurred, the heating power of the evaporation chamber 51 was automatically adjusted. Simultaneously, differential pressure sensor monitored the pipeline back pressure in real time. If the differential pressure abnormally increased, it indicated a localized salt deposition trend, and the carrier gas flow rate was immediately adjusted through the mass flow control system. Particle size monitoring probes provided real-time feedback to the mixing device 2 based on the salt vapor particle size distribution, dynamically correcting the preheating temperature.

[0107] Sp8. End of Experiment and High-Temperature Purging Phase:

[0108] After the preset test cycle is reached, the feeding action of the micro-screw feeder 12 is stopped first. The automatic purging system in the auxiliary support unit is started, and a large flow of high-temperature dry nitrogen gas is introduced into the system. The purging airflow maintains a high temperature and flushes the entire flow path of the evaporation chamber 51, the high-temperature feeding pipe 3, and the heated conveying pipe 6, completely removing any residual trace salt from the system. This prevents salt crystallization during equipment cooling from causing permanent corrosion or blockage of the pipelines, ensuring a clean initial environment for the next experiment.

[0109] The core logic of this method lies in constructing the entire physical evolution process of "solid-to-gas conversion, superheated transport, and directional condensation." Through Sp1 to Sp4, the efficient conversion of the corrosive medium from a macroscopic solid to a microscopic gaseous phase is achieved, and the limitations of molten salt surface evaporation kinetics are overcome using air knife ablation technology. Sp5 and Sp6, through positive temperature gradients and annular sheath flow technology, solve the problems of condensation blockage and diffusion distortion in the high-temperature salt vapor transport process, achieving precise deposition of the corrosive medium in a multi-field coupled environment. Finally, through the closed-loop control system of Sp7, the previously invisible evaporation and deposition process is transformed into monitorable and quantifiable engineering parameters, significantly improving the high fidelity and repeatability of marine high-temperature environment simulation.

[0110] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An evaporator simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment, characterized in that, include: A precision funnel feeding device (1) is used to store and quantitatively convey dry salt powder; a mixing device (2) is connected to the outlet of the precision funnel feeding device (1) and is used to initially mix the salt powder with the carrier gas to form a gas-solid two-phase flow; a high-temperature feeding pipe (3) is connected at one end to the outlet of the mixing device (2) and at the other end to the inlet of the evaporation device (5) and is used to convey the gas-solid two-phase flow to the evaporation device; the evaporation device (5) is used to receive the salt powder and heat it to a molten evaporation state to generate salt vapor; a heat-traced conveying pipe (6) is connected at one end to the vapor outlet of the evaporation device (5) and at the other end to the external test chamber and is used to convey the salt vapor to the test area at a high temperature; a double-layer aluminum silicate insulation layer (4) is wrapped around the high-temperature feeding pipe (3), the evaporation device (5) and the heat-traced conveying pipe (6) and is used to reduce heat loss and maintain temperature uniformity.

2. The evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment according to claim 1, characterized in that: The precision funnel feeding device (1) includes: a moisture-proof hopper (11), which is equipped with a heating and insulation layer and a desiccant inside to keep the salt powder dry; a micro screw feeder (12), installed at the bottom of the moisture-proof hopper (11), for quantitatively conveying the salt powder at a rate of 0.01-5 g / min; and an anti-bridging vibrator (13), connected to the moisture-proof hopper (11), for preventing the salt powder from arching and clogging inside the hopper; the mixing device (2) includes: a mixing chamber (21), which is equipped with a static mixing element inside; and a carrier gas inlet (22), which is located on the side wall of the mixing chamber (21), for introducing dry carrier gas preheated to above 600°C; the mixing chamber (21) mixes the salt powder and carrier gas evenly. The gas-solid two-phase flow is formed by uniform mixing; the high-temperature feeding pipe (3) has a double-layer structure, with the inner layer being a high-temperature and corrosion-resistant material and the outer layer being a double-layer aluminum silicate insulation layer (4), and multiple temperature monitoring points are provided along the length of the pipe; the evaporation device (5) includes: an evaporation chamber (51) made of a high-temperature and molten salt corrosion-resistant material, with an electric heating element wrapped around the outside; an evaporation container (52) located inside the evaporation chamber (51) for holding and heating the salt raw material to a molten state; and a preheating carrier gas introduction structure (53) located inside the evaporation chamber (51) and close to the liquid surface of the evaporation container (52) for introducing the preheating carrier gas in a laminar flow form close to the molten salt surface, peeling off and carrying away the evaporated salt.

3. The evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment according to claim 2, characterized in that: The evaporation container (52) has a shallow dish-shaped structure and is made of platinum-rhodium alloy or tantalum-tungsten alloy. A weight sensor (54) is provided at the bottom of the evaporation container (52) to monitor the change in the quality of the salt raw material in real time. The preheating carrier gas introduction structure (53) is a slit nozzle or a micro-hole array nozzle, and its outlet direction is parallel to or at an acute angle to the molten salt surface. The carrier gas flow rate is 1-10 L / min.

4. The evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment according to claim 1, characterized in that: The heat tracing pipeline (6) is divided into multiple independent temperature control sections along its length. The temperature control setting value of each temperature control section increases along the direction of salt vapor flow to form a positive temperature gradient and prevent salt vapor from condensing and depositing. The end of the heat tracing pipeline (6) is provided with an injection nozzle (61). A concentric sleeve (62) is provided around the injection nozzle (61) to introduce clean gas to form an annular sheath flow and constrain the salt vapor stream.

5. The evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment according to claim 1, characterized in that: It also includes a precision control and monitoring unit, which includes: a multi-level temperature control system, which independently controls the temperature of each temperature zone of the evaporation device (5) and the heat tracing pipeline (6); a mass flow control system, which controls the flow rate of the carrier gas and the flow rate of the sheath gas; and process monitoring sensors, including a weight sensor (54) set at the bottom of the evaporation container, a differential pressure sensor set at a key point of the heat tracing pipeline (6), and a particle size monitoring probe set at the outlet of the injection nozzle 61.

6. The evaporator for simulating multi-field coupled corrosion of salt vapor in a high-temperature marine environment according to claim 1, characterized in that: It also includes an auxiliary support unit, which includes: an automatic purging system connected to a drying carrier gas source for high-temperature purging of the evaporation device (5) and the heat tracing pipeline (6); and a safety interlock system connected to a monitoring sensor signal for automatically triggering an alarm and performing a safe shutdown in abnormal conditions.

7. A method for high-temperature salt spray corrosion testing of nickel-based superalloys using an evaporator according to any one of claims 1-6, characterized in that, Includes the following steps: Sp1: System preheating, heating the evaporator (5) and the heat tracing pipeline (6) to the preset temperature; Sp2: Introduce preheated carrier gas to establish a stable carrier gas flow field; Sp3: Start the precision funnel feeding device (1) to feed the dry salt powder into the mixing device (2) in a quantitative manner. After mixing with the carrier gas, it enters the evaporation device (5) through the high temperature feeding pipe (3). Sp4: The salt powder melts and evaporates in the evaporation device (5), and the generated salt vapor is stripped off by the carrier gas that is closely attached to the surface of the molten salt; Sp5: Salt vapor is transported to the test chamber through the heated pipeline (6) under high temperature tracing throughout the process and injected into the high temperature gas flow; Sp6: Salt vapor condenses and deposits on the surface of a nickel-based superalloy sample to form a molten salt film, which is then used for hot corrosion testing. Sp7: Real-time monitoring of temperature, flow rate, mass changes, and differential pressure; dynamic parameter adjustment. Sp8: After the test is completed, stop feeding and perform high-temperature purging to remove residual salt.

8. A method for high-temperature salt spray corrosion testing of nickel-based superalloys using an evaporator according to claim 7, characterized in that: The preset temperatures in Sp1 are: 800-950℃ in the evaporator (5), and 20-150℃ higher in each temperature zone of the heat-tracing pipeline (6) than in the evaporator, increasing along the flow direction; the carrier gas in Sp2 is nitrogen or dry air, with a flow rate of 1-10L / min and a preheating temperature ≥600℃; the salt powder in Sp3 is one or more of sodium chloride, potassium chloride, and sodium sulfate, with a feeding rate of 0.01-5g / min; the high-temperature gas flow temperature in Sp5 is 800-1600℃, and the nickel-based high-temperature alloy sample is selected from one or more of GH4169, GH4742, GH4720Li, GH4738, and GH4698, with the sample surface temperature controlled at 900-1200℃; the dynamic adjustment in Sp7 includes: adjusting the evaporation temperature according to the deviation between the mass change rate of the evaporator 52 and the feeding rate, adjusting the carrier gas flow rate or triggering purging according to the pipeline pressure difference, and adjusting the mixing chamber temperature according to the particle size monitoring data.

Images