Method for simulating and evaluating corrosion of condensation tube bundle of air conditioner in marine atmospheric environment

Abstract

The invention provides a method for simulating and evaluating corrosion of an air conditioner condensation tube bundle in a marine atmospheric environment. A corrosion coupon and an impedance measurement probe are adopted to research corrosion behaviors of an air conditioner heat exchange tube and a fin working in the marine atmospheric environment. A simulation test device for simulating the heat exchange environment of an air conditioner is adopted in the test, when the device is used, the temperature of a hot fluid storage chamber and the temperature of a cold fluid storage chamber are set, and the temperature of the hot fluid storage chamber is controlled by a heating wire and a thermocouple; the temperature of the cold fluid storage chamber is controlled by a condenser pipe and a thermocouple. After the fluid in the storage chamber reaches a set temperature, an underflow pump in the hot fluid storage chamber is opened, and water starts to circulate in a heat conduction pipe in the test cabin. After circulation is carried out for a period of time and the temperature sensors in the storage chamber and on the surface of the heat conduction pipe are stable, the simulation test piece and the like are placed on the heat conduction pipe, the internal salt mist generator is turned on, and the test is started. In the test process, the temperature and humidity changes in the test cabin are detected by an internal temperature and humidity meter.

Description

Technical Field

[0001] The invention relates to the field of corrosion simulation evaluation of air-conditioning condensing tube bundles, and in particular to a corrosion simulation evaluation method of air-conditioning condensing tube bundles in a marine atmosphere environment. Background Art

[0002] Air conditioners are indispensable civilian electrical appliances and are also an important guarantee for the safe operation of industrial and military facilities. During the use of air conditioners, corrosion problems continue to occur. For example, the southern coastal areas of my country are hot and rainy all year round, with high concentrations of salt and fog, and a harsh environment, which has a serious impact on the corrosion of metal components of marine facilities, and the corrosion will affect the performance of air conditioners. For air conditioner heat exchangers, heat exchangers and heat dissipation fins are in a high and low temperature change environment, and condensation water is easily formed on the surface. Once chloride ions and other corrosive ions in the atmospheric environment, such as sulfur dioxide and carbon dioxide, are absorbed, the corrosion of pipelines and fins is very serious. At present, the material selection and rating, corrosion simulation, etc. of heat exchangers and heat sinks are mainly carried out with reference to national standards for salt spray tests or simulation tests. The commonly used experimental standards include GB / T 10125-2021 "Corrosion tests in artificial atmospheres-Saltspray tests", ISO 9227:2017 "Corrosion tests in artificial atmospheres-Saltspray tests", GB / T 2423.17-2008 "Basic environmental testing procedures for electric and electronic products Test Ka: Salt spray test method", GB / T 2423.18-2000 "Environmental testing for electric and electronic products Part 2: Test Kb: Salt spray, alternating (sodium chloride solution)", GB 5938-86 "Corrosion resistance test method for metal coatings and chemically treated layers of light industrial products" and acetic acid salt spray test (AASS) and copper accelerated acetic acid salt spray test (CASS), which are carried out at different pH values ​​and conditions to simulate different corrosion environments.

[0003] The above-mentioned accelerated test and simulation test methods all use salt spray environment to corrode materials and evaluate their corrosion rate and corrosion behavior. However, the working environment of air-conditioning heat exchange tubes and fins is different from that of salt spray environment, especially there is a significant temperature difference between the air-conditioning external unit and the indoor main unit, the working temperature distribution of heat exchange tubes and fins is uneven, and the corrosion behavior and corrosion rate of various parts vary greatly during long-term operation. Therefore, the design and development of simulation corrosion methods for air-conditioning heat exchange tubes and fins, the study of their corrosion behavior and corrosion process, have obvious practical significance for the optimization of heat exchange tube and fin material structure, etc. Summary of the invention

[0004] The purpose of the present invention is to provide a corrosion behavior test method that simulates the actual working conditions of air-conditioning heat exchange tubes, and use corrosion coupons and impedance measurement probes to study the corrosion behavior of air-conditioning heat exchange tubes and fins working in a marine atmosphere environment. The corrosion rate and corrosion behavior of heat exchange tubes and fins under different temperature fields can be explored, providing an effective research method for material optimization.

[0005] It can simulate the corrosion of air conditioning condenser tube bundles in marine atmosphere environments at different temperatures, study its corrosion mechanism or optimize materials based on the corrosion rate.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for simulating and evaluating the corrosion of air-conditioning condenser tube bundles under marine atmospheric environment, which is realized by adopting a corrosion behavior test method simulating the actual working conditions of air-conditioning heat exchange tubes, and using corrosion coupons and impedance probes to detect and study the corrosion behavior of the simulated environment.

[0007] During the test, the temperature of the hot fluid storage chamber 1 and the cold fluid storage chamber 2 are set respectively. The temperature of the hot fluid storage chamber is controlled by the heating wire 5 and the thermocouple 6; the temperature of the cold fluid storage chamber 2 is controlled by the condenser 13 and the thermocouple 12. After the fluid in the storage chamber reaches the set temperature, the submerged flow pump 4 in the hot fluid storage chamber is turned on, and water begins to circulate in the heat pipe 7 in the test chamber 3. After a period of circulation, when the temperature sensors 9 in the storage chamber and on the surface of the heat pipe are stable, the simulated test piece 10 is placed on the heat pipe, the internal salt spray generator 8 is turned on, and the test is started; during the test, the temperature and humidity changes in the test chamber are detected by the internal temperature and humidity meter 11.

[0008] The designed heat transfer pipe is connected to the cold and hot fluid storage chamber, and the submerged flow pump circulates the fluid in the storage chamber. A certain temperature gradient is formed on the surface of the heat transfer pipe to simulate the actual working conditions of the heat exchange pipe in the air conditioning environment.

[0009] The circulation flow rate of the submerged flow pump varies according to the temperature and fluid properties, and the flow rate control range is 10-500L / h. The flow rate is adjusted according to the temperature change of the heat transfer pipe surface, and the final flow rate is when the temperature reaches a stable state.

[0010] The heat pipe is made of copper and processed into an oblate shape to facilitate the installation of corrosion hanging pieces. It can also be replaced with stainless steel according to the corrosion situation.

[0011] Both hot and cold storage rooms and test chambers are covered with thermal insulation materials to prevent heat loss.

[0012] The salt spray generator in the test chamber can adjust the salt content according to the simulated on-site conditions.

[0013] The beneficial effects of the present invention are: The temperature of the hot and cold fluid storage chambers is controlled separately, and the heat transfer pipes for heat exchange have a real temperature distribution gradient, which can realize the real simulation of the actual corrosion environment. The test chamber is used to simulate the external atmospheric environment, and the corrosion behavior of materials under different temperature fields can be studied. The salt spray generator can prepare the solution according to the concentration of chloride ions or other corrosive ions in the specific atmospheric corrosion environment to simulate the corrosion behavior of materials in the marine atmospheric environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the device simulating air conditioning heat exchange environment; Figure 2 Schematic diagram of the temperature field distribution of the heat pipe during the test; Figure 3 Schematic diagram of corrosion weight loss results. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the embodiments, but is not limited thereto.

[0016] Example A simulation evaluation method for corrosion of air conditioning condenser tube bundles in a marine atmosphere environment is implemented by adopting a corrosion behavior test method simulating the actual working conditions of air conditioning heat exchange tubes, and using corrosion coupons and impedance probes to detect the corrosion behavior of the simulated environment; During the test, the temperatures of the hot fluid storage chamber 1 and the cold fluid storage chamber 2 are set respectively, and the temperature of the hot fluid storage chamber is controlled by the heating wire 5 and the thermocouple 6; the temperature of the cold fluid storage chamber 2 is controlled by the condenser 13 and the thermocouple 12; after the fluid in the storage chamber reaches the set temperature, the submerged flow pump 4 in the hot fluid storage chamber is turned on, and water begins to circulate in the heat pipe 7 in the test chamber 3; after a period of circulation, when the temperature sensors 9 in the storage chamber and on the surface of the heat pipe are stable, the simulated test piece 10 is placed on the heat pipe, the internal salt spray generator 8 is turned on, and the test is started; during the test, the internal temperature and humidity meter 11 detects changes in temperature and humidity in the test chamber.

[0017] The heat pipe 7 connects the hot fluid storage chamber 1 and the cold fluid storage chamber 2, and the submerged flow pump 4 circulates the fluid in the hot fluid storage chamber 1 and the cold fluid storage chamber 2; a temperature gradient is formed on the surface of the heat pipe 7 to simulate the actual working condition of the heat exchange pipe in the air-conditioning environment.

[0018] The circulation flow rate of the submerged flow pump 4 varies according to the temperature and fluid properties, and the flow rate control range is 10-500L / h; the flow rate is adjusted according to the temperature change of the heat pipe surface, and the final flow rate is when the temperature reaches a stable state.

[0019] The heat conducting pipe 7 is made of copper or stainless steel and is processed into an oblate shape to facilitate the installation of corrosion hanging pieces.

[0020] The hot fluid storage chamber 1, the cold fluid storage chamber 2 and the test chamber 3 are all covered with heat-insulating materials to prevent heat loss.

[0021] The salt spray generator 8 in the test chamber 3 adjusts the salt content according to the simulated on-site conditions.

[0022] Taking the atmospheric corrosion environment in Wenchang, Hainan as an example, the corrosion behavior of air conditioning heat exchange tubes and condenser fins in Wenchang area was studied. The heat exchange tube bundle is made of copper alloy, and the fin material is aluminum alloy. The heat exchange tube bundle and fins are not treated with anti-corrosion. The atmospheric chloride ion precipitation in Wenchang is 0.54mg / (1dm 2 .d) (mg per square decimeter.day), the calculated chloride ion concentration of the salt spray solution is about 1 mol / L. The atmospheric humidity in Wenchang in summer is about 90%.

[0023] Sample preparation: Copper plates and aluminum plates were used to process corrosion specimens with a size of 30mm×30mm×1-2mm. The specimens can be designed according to the temperature field distribution. This test is for 6 different temperature fields, so 6 points×4 pieces×3 times were selected. Among the 4 pieces, 1 piece is a sample for surface morphology analysis, 3 pieces are samples for corrosion rate analysis and corrosion depth analysis, and 3 is the number of sampling. After being processed by milling and grinding machines to a smoothness of ▽7 or above, one working surface of the specimen is retained for corrosion testing, and the remaining surfaces are sealed with 704 silicone or wax. The retained working surface is degreased and cleaned with a degreaser, dehydrated with ethanol, blown dry, placed in a dryer for 24 hours, and weighed with an electronic balance with an accuracy of 0.0001g. Copper and aluminum materials are respectively processed into impedance probes and connected to the electrochemical workstation.

[0024] The 1# and 4# test points are located near the hot fluid storage room; the 3# and 6# test points are located near the cold fluid storage room; the 2# and 5# test points are located in the middle of the heat pipe.

[0025] Test method: Set the specified temperature of the hot and cold fluid storage chambers of the simulation test device, where the temperature of the hot fluid storage chamber is controlled at 50°C and the temperature of the cold fluid storage chamber is controlled at 5°C. Install the prepared corrosion specimen on the heat pipe of the test chamber, keeping the working surface facing up. Load the prepared sodium chloride solution with a concentration of about 1 mol / L into the salt spray generator. After the hot and cold fluid storage chambers reach the set temperature, turn on the submerged flow pump and control the flow rate at 10L / h to circulate the water in the two storage chambers. Then turn on the salt spray generator, and the test chamber forms a high humidity and high salt environment. The salt spray content in the test chamber is controlled by a thermometer and hygrometer to keep the humidity at about 90%. The heat pipe forms different temperature fields under the action of the fluid, and the temperature changes continuously with the cycle. At this time, the surface temperature change is recorded according to the temperature sensor installed on the surface of the heat pipe.

[0026] After 10 days of simulation test, the submerged pump was turned off, the temperature control and heating and refrigeration devices of the hot and cold fluid storage chambers were turned off, and the salt spray generator was turned off. The sample was taken out of the test chamber for surface morphology analysis, corrosion rate analysis and corrosion depth analysis. The post-treatment was to clean the surface corrosion products, rinse the surface with alcohol, blow dry with a hair dryer, and weigh; the surface morphology analysis used epoxy resin to encapsulate the sample and the rust layer, and then use a scanning electron microscope to examine the morphology of the rust layer section; the corrosion rate analysis and corrosion depth analysis process was to soak the sample with liquid to remove the corrosion products. The composition of the solution used for aluminum alloy was: 5% to 10% NaOH solution at 40℃ to 70℃ for 3 min to 7 min, rinse with running water; then pickled with 30% HNO3 solution at room temperature to 60℃ for 1 min to 3 min, rinse with running water, and air dry or low-temperature dry. The composition of the solution used for copper alloy was: 70% acetic acid aqueous solution, soak for 3-5min and clean the surface with a soft brush.

[0027] Data Analysis: From the analysis of the sample surface morphology photos, there are obvious differences in material corrosion at different temperature fields. The corrosion of samples close to the low-temperature storage room is more serious. This is related to the fact that thin liquid film and liquid are more easily formed on the material surface at lower temperatures.

[0028] Matters not covered by the present invention are known technologies.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A simulation evaluation method for corrosion of air conditioning condenser tube bundles in a marine atmosphere environment, characterized in that: The simulation evaluation method for corrosion of air conditioning condenser tube bundles in marine atmosphere environment is realized by adopting a corrosion behavior test method simulating the actual working conditions of air conditioning heat exchange tubes, and using corrosion coupons and impedance probes to detect the corrosion behavior of the simulated environment; During the test, the temperature of the hot fluid storage chamber (1) and the cold fluid storage chamber (2) are set respectively. The temperature of the hot fluid storage chamber is controlled by the heating wire (5) and the thermocouple (6); the temperature of the cold fluid storage chamber (2) is controlled by the condenser (13) and the thermocouple (12); after the fluid in the storage chamber reaches the set temperature, the submerged flow pump (4) in the hot fluid storage chamber is turned on, and water begins to circulate in the heat pipe (7) in the test chamber (3); after a period of circulation, when the temperature sensors (9) in the storage chamber and on the surface of the heat pipe are stable, the simulated test piece (10) is placed on the heat pipe, the internal salt spray generator (8) is turned on, and the test is started; during the test, the temperature and humidity changes in the test chamber are detected by the internal temperature and humidity meter (11).

2. The method for simulating and evaluating corrosion of air conditioning condenser tube bundles in a marine atmosphere environment according to claim 1, characterized in that: The heat conducting pipe (7) connects the hot fluid storage chamber (1) and the cold fluid storage chamber (2), and the submerged flow pump (4) circulates the fluid in the hot fluid storage chamber (1) and the cold fluid storage chamber (2); a temperature gradient is formed on the surface of the heat conducting pipe (7) to simulate the actual working condition of the heat exchange pipe in an air conditioning environment.

3. The method for simulating and evaluating corrosion of air conditioning condenser tube bundles in a marine atmosphere environment according to claim 1, characterized in that: The circulation flow rate of the submerged flow pump (4) varies according to the temperature and fluid properties, and the flow rate control range is 10-500L / h; the flow rate is adjusted according to the change of the surface temperature of the heat transfer pipe, and the final flow rate is when the temperature reaches a stable state.

4. The method for simulating and evaluating corrosion of air conditioning condenser tube bundles in a marine atmosphere environment according to claim 1, characterized in that: The heat conducting pipe (7) is made of copper or stainless steel and is processed into an oblate shape to facilitate the installation of corrosion-resistant hanging pieces.

5. The method for simulating and evaluating corrosion of air conditioning condenser tube bundles in a marine atmosphere environment according to claim 1, characterized in that: The hot fluid storage chamber (1), the cold fluid storage chamber (2) and the test chamber (3) are all covered with heat-insulating materials to prevent heat loss.

6. The corrosion simulation evaluation method for air conditioning condenser tube bundles in a marine atmosphere environment according to claim 1 is characterized in that: The salt spray generator (8) in the test chamber (3) adjusts the salt content according to the simulated on-site conditions.

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