A plate type micro-channel organic working medium boiling heat exchange test system

Abstract

This invention proposes an experimental system for boiling heat transfer of organic working fluids within a plate-type microchannel, belonging to the field of nuclear reactor thermal-hydraulic technology. It solves the problem of lacking a system for studying the heat transfer characteristics and mechanisms of organic working fluids within plate-type microchannels. It includes a closed-loop connected storage tank, working fluid pump, preheating section, experimental section, and cooler. The experimental section has an observation window on its top cover, with a glass cover plate placed underneath. The microchannel section is attached to the lower part of the glass cover plate, and a thermocouple is installed at the bottom of the microchannel section. Inlet and outlet ports are located at both ends of the microchannel section, and a heating section is installed at the bottom of the microchannel section, with a base plate at its bottom. This experimental system exhibits good sealing performance under medium to high pressure, making it suitable for experimental studies using organic working fluids and preventing leakage of irritating working fluids. The microchannel section of this invention has a large aspect ratio; its sufficient length ensures comprehensive observation of the flow pattern and the integrity of the boiling process.

Description

Technical Field

[0001] This invention belongs to the field of nuclear reactor thermal-hydraulic technology, and in particular relates to a test system for boiling heat exchange of organic working fluid in a plate microchannel. Background Technology

[0002] In marine environments, small reactor systems retain a significant amount of low-grade waste heat in the exhaust steam of turbines. Efficient recovery and utilization of this heat energy can greatly improve system efficiency. Currently, waste heat recovery systems using water as the working fluid mostly operate in the single-phase heat transfer region, resulting in low recovery efficiency. Organic working fluids, with their low boiling points, can still achieve phase change heat transfer even under low-grade waste heat conditions, demonstrating great potential for improving waste heat recovery efficiency.

[0003] However, due to the low thermal conductivity and Prandtl number of organic working fluids, the hot-end and cold-end heat exchange equipment of organic Rankine cycle systems is bulky and expensive, significantly reducing the system's technical and economic performance. Plate microchannel evaporators, with their advantages of small size, high compactness, and high heat exchange performance, are an effective way to reduce the size of the hot and cold-end equipment in organic Rankine cycle systems and improve their performance. Furthermore, plate microchannel waste heat recovery systems based on organic working fluids can maintain a compact size while improving energy utilization efficiency when applied to small reactors, offering significant advantages in space- and weight-constrained scenarios.

[0004] Plate-type microchannel evaporators consist of numerous microchannels. Compared to traditional large-scale channels, the fluid flow within these microchannels experiences different forces, exhibiting varying flow characteristics and conversion mechanisms. In particular, the two-phase flow within microchannels displays different heat transfer and resistance characteristics depending on the flow pattern. Furthermore, the wide variety of organic working fluids leads to variations in the operating conditions of different types of evaporators. In summary, existing flow pattern, heat transfer, and resistance models are insufficient to support the design and development of novel plate-type microchannel steam generators, significantly limiting the advancement of organic Rankine cycle applications in practical engineering. Summary of the Invention

[0005] In view of this, in order to address the need for a system that studies the heat transfer characteristics and mechanisms of organic working fluids in plate microchannels, a test system for boiling heat transfer of organic working fluids in plate microchannels is provided, which enables the visualization study of the boiling heat transfer characteristics of organic working fluids in microchannels.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a plate-type microchannel organic working fluid boiling heat exchange test system, comprising a liquid storage tank, a working fluid pump, a preheating section, an experimental section, and a cooler connected in a closed loop; The experimental section includes a top cover, a glass cover plate, a microchannel section, a water inlet, a water outlet, a heating section, and a base plate. The top cover has an observation window, and the glass cover plate is placed under the top cover. The microchannel section is attached to the lower part of the glass cover plate, and a thermocouple is installed at the bottom of the microchannel section. The water inlet and water outlet are respectively provided at both ends of the microchannel section. The heating section is installed at the bottom of the microchannel section, and a base plate is provided at the bottom of the heating section.

[0007] Furthermore, the plate-type microchannel organic working fluid boiling heat exchange test system also includes control equipment, which includes a back pressure valve and a regulating valve. The back pressure valve and the regulating valve are installed between the working fluid pump and the preheating section, respectively, for adjusting the working fluid pressure and the working fluid flow rate.

[0008] Furthermore, the control device includes a pressure regulator, which is installed between the working fluid pump and the back pressure valve. The pressure regulator is a pressure stabilizing tank filled with nitrogen.

[0009] Furthermore, the control device includes a first DC power supply and a second DC power supply, the first DC power supply being connected to the preheating section and the second DC power supply being connected to the experimental section.

[0010] Furthermore, the control device includes a constant temperature water tank, which is connected to a cooler.

[0011] Furthermore, the preheating section includes a stainless steel pipe and an insulating flange. The DC power supply first electrically heats the stainless steel pipe to achieve preheating, and a thermocouple is installed at the outlet of the stainless steel pipe for temperature measurement. Insulating flanges are installed at both ends of the stainless steel pipe for insulation.

[0012] Furthermore, the plate-type microchannel organic working fluid boiling heat exchange test system also includes measurement and monitoring equipment, including a flow meter, thermocouples and a pressure sensor. The flow meter is located between the working fluid pump and the preheating section and is used to measure the working fluid flow rate. Thermocouples are arranged on the preheating section and the test section to measure the temperature. A pressure sensor is set between the preheating section and the test section to measure the pressure in the circuit and in the test section.

[0013] Furthermore, the working fluid pump is a mechanically driven diaphragm metering pump.

[0014] Furthermore, the cooler is a tubular heat exchanger made of 316L stainless steel.

[0015] A method for using a plate-type microchannel organic working fluid boiling heat transfer test system includes the following steps: Step 1: Before the experiment begins, turn on the signal acquisition system of the entire system. Observe the pressure and temperature in the circuit through the pressure sensor and thermocouple to perform initial state detection. After the detection is normal, fill the storage tank 1 with working fluid, then open the storage tank valve and working fluid pump to allow the working fluid to flow fully in the circuit. Use the pressure stabilizing tank filled with nitrogen to stabilize the circuit and adjust the pressure through the back pressure valve. Step 2: After the working fluid has flowed sufficiently for a period of time, first turn on the pump in the constant temperature water tank circuit of the cooler to input cooling water, then turn on the first DC power supply of the preheating section for preheating, and continue to monitor temperature and pressure changes through the acquisition system. If there are no abnormalities, turn on the electric heating device of the experimental section to heat the experimental section. Monitor temperature data through thermocouples in the experimental section, collect visual data through the visualization window captured by the high-speed camera, monitor the mass flow rate in the circuit through the flow meter, and adjust different mass flow rates through the adjusting handwheel of the regulating valve. After collecting enough data, turn off the heating device of the experimental section and continue to monitor temperature and pressure. After there are no abnormal fluctuations, turn off the first DC power supply of the preheating section and the cooling water circuit pump. Step 3: After the system pressure drops to the minimum, close the inlet and outlet valves of the experimental section and replace the microchannel section. If the experiment is not to continue, close the outlet valve of the storage tank and open the inlet and outlet valves of the experimental section to discharge the working fluid through the drain outlet. After the liquid is drained, close the remaining valves and working fluid pump. When conducting experiments under marine conditions, place the entire system on a six-degree-of-freedom platform. With the rest of the operations unchanged, turn on the six-degree-of-freedom platform before heating the experimental section to drive the experimental system to perform the specified form of motion. Then conduct subsequent experiments and data monitoring. After collecting enough data, turn off the six-degree-of-freedom motion platform. The subsequent processing is the same as for experiments under non-marine conditions.

[0016] Compared with the prior art, the beneficial effects of the plate-type microchannel organic working fluid boiling heat transfer test system described in this invention are: 1. The experimental system of this invention has good sealing performance under medium and high pressure, making it suitable for experimental research using organic working fluids and preventing leakage of irritating working fluids.

[0017] 2. The microchannel segment designed in this invention has a large aspect ratio of 494:1. The sufficient length can ensure the comprehensiveness of flow pattern observation and the integrity of the boiling process.

[0018] 3. The experimental system of this invention can perform experiments to visually observe the flow pattern. By pressing the glass, the entire process of the organic working fluid from single phase to boiling can be observed directly.

[0019] 4. The experimental system of this invention is designed with real dimensions, eliminating the need for scaled evaluation of the test bench, and has good applicability to practical engineering applications.

[0020] 5. This invention captures the entire process of organic working fluid from single phase to boiling by controlling conditions such as inlet flow rate, inlet subcooling, and heat flux density to change thermal parameters, as well as the diameter and geometric parameters of the heat channel of the plate microchannel. According to research needs, it can obtain the visualization characteristics and heat transfer characteristics of organic working fluid in the plate microchannel, such as subcooled boiling and saturated boiling. It can also define the boundaries of various flow patterns and understand the evolution process of different boiling phenomena.

[0021] 6. By arranging temperature measuring points, this invention can obtain temperature change data of the entire process of boiling heat transfer of organic working fluid in microchannels, thereby enabling the study of the boiling heat transfer mechanism of organic working fluid in microchannels.

[0022] 7. This invention has a simple layout and occupies a small space, making it highly applicable for studying the boiling heat transfer characteristics of organic working fluids. Furthermore, when combined with a six-degree-of-freedom platform, it can be used to study the boiling heat transfer characteristics of organic working fluids in microchannels under marine conditions, thus expanding the research scope. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the experimental system for boiling heat transfer of organic working fluid in a plate-type microchannel according to the present invention; Figure 2 A schematic diagram of a marine condition platform system that works in conjunction with the experimental system of this invention; Figure 3 This is a schematic diagram of the experimental section structure in this invention; Figure 4 This is a front view of the experimental section in this invention; Figure 5 This is a top view of the experimental section in this invention; Figure 6 This is a side view of the experimental section in this invention; In the diagram: 1. Storage tank; 2. Working fluid pump; 3. Back pressure valve; 4. Flow meter; 5. Regulating valve; 6. Preheating section; 7. DC power supply No. 1; 8. Constant temperature water tank; 9. Cooler; 10. Experimental section; 11. DC power supply No. 2; 12. Pressure sensor; 13. Top cover; 14. Glass cover; 15. Microchannel; 16. Inlet; 17. Outlet; 18. Heating section; 19. Base plate. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0025] See Figure 1-6 This embodiment describes an organic working fluid boiling heat exchange test system in a plate-type microchannel, comprising a liquid storage tank 1, a working fluid pump 2, a preheating section 6, an experimental section 10, and a cooler 9 connected in a closed loop. The plate-type microchannel organic working fluid boiling heat exchange test system also includes control equipment, which includes a back pressure valve 3, a regulating valve 5, a first DC power supply 7, a constant temperature water tank 8, and a second DC power supply 11. The back pressure valve 3 and the regulating valve 5 are located between the working fluid pump 2 and the preheating section 6, and are used to regulate the working fluid pressure and flow rate, respectively. The constant temperature water tank 8 is connected to the cooler 9, the first DC power supply 7 is connected to the preheating section 6, and the second DC power supply 11 is connected to the experimental section 10.

[0026] The plate-type microchannel organic working fluid boiling heat exchange test system also includes measurement and monitoring equipment, including a flow meter 4, a thermocouple and a pressure sensor 12. The flow meter 4 is located between the working fluid pump 2 and the preheating section 6 and is used to measure the working fluid flow rate. Thermocouples are arranged on the preheating section 6 and the test section 10 and are used to measure the temperature. The pressure sensor 12 is set between the preheating section 6 and the test section 10 and is used to measure the pressure in the circuit and in the test section 10.

[0027] The storage tank 1 is positioned at the lowest point of the entire system to facilitate gravity-based recovery of the working fluid. Its inlet is connected to the outlet of the cooler 9, and its outlet is connected to the inlet of the working fluid pump 2. After the working fluid in the storage tank 1 enters the working fluid pump 2, the pump 2 ensures that the working fluid flows freely within the circuit.

[0028] The volume of the storage tank 1 is greater than the working fluid required for the loop flow, and needs to be calculated based on the overall experimental loop. In this invention, the volume of the storage tank 1 fully meets the experimental requirements, and it is a vertical storage tank with good sealing and corrosion resistance. The working pressure can also meet the experimental requirements.

[0029] The working fluid pump 2 is a mechanically driven diaphragm metering pump. Considering the issues of corrosiveness, low flow rate, and sealing, this type of pump is highly adaptable to flow experiments with organic working fluids. The pump is equipped with an adjusting handwheel, which allows for stepless percentage-based flow rate adjustment; one rotation adjusts the flow rate by 10%, with an adjustment error not exceeding 2%. The pump head is also sufficiently large, and the head can be determined based on the total pressure loss of the experimental circuit.

[0030] The pressure regulator uses a nitrogen-filled pressure vessel, specifically a stainless steel pressure vessel with a threaded connection. The factory preset pressure can be set, but filling requires a gas filling device; the specific volume and weight must be determined based on experimental requirements.

[0031] The flow meter 4 is a mass flow meter with a flow measurement range of 0-30 kg / h and an accuracy of 0.25%. After being plugged in, the flow can be read directly on the display screen or connected to a computer for continuous data acquisition. The differential pressure transmitter 11 has a pressure measurement range of 0-100 kPa and an accuracy of 0.075%. After being plugged in, it can be read directly on the display screen or connected to a computer for continuous data acquisition. The diaphragm located in the center of the transmitter sensor module is made of 316L stainless steel and filled with silicone resin.

[0032] Except for the preheating section which is heated by a separate stainless steel pipe, all pipelines are made of DN10 PVC pipes and are connected by welding.

[0033] The preheating section 6 includes a stainless steel heating pipe and insulating flanges. Preheating is achieved by electrically heating the stainless steel pipe using a DC power supply 7. A thermocouple is installed at the outlet for temperature measurement, allowing for temperature control by adjusting the power supply output. Insulating flanges are installed at both ends of the stainless steel pipe for insulation. This heating method is simple to arrange, has a short heating time, and the insulating flanges ensure experimental safety. The rated voltage, rated current, size, and model of the DC power supply 7 must be selected according to experimental requirements. It is connected by wrapping heating wire around the stainless steel pipe and then connecting the DC power supply to the heating wire.

[0034] The cooler 9 is primarily a tubular heat exchanger, which, together with the constant-temperature water tank 8, forms the cooling section. The tubular heat exchanger is characterized by its simple and compact structure, further reducing the overall system size. The preferred material for the heat exchanger is 316L stainless steel to achieve corrosion and leakage prevention. The flow rate and pressure requirements need to be selected based on the specific heat exchange characteristics of the organic working fluid. The water in the constant-temperature water tank 8 serves as the cold source for cooling the working fluid. It has its own pump, eliminating the need for an external circulation pump. Its simple structure facilitates operation and ensures the water temperature is maintained at a low level, unaffected by ambient temperature. A flexible hose connects the constant-temperature water tank 8 to the tubular heat exchanger. The model, volume, and built-in pump flow rate of the constant-temperature water tank need to be selected and set according to the experimental conditions.

[0035] The experimental section 10 mainly consists of a top cover 1-1, a glass cover plate 1-2, a microchannel section 1-3, a water inlet 1-4, a water outlet 1-5, a heating section 1-6, and a base plate 1-7. The top cover 1-1 and the base plate 1-7 are made of 316L stainless steel and are connected by tensile bolts to secure the entire experimental section, ensuring the strength of the experimental body and the connection. The top cover 1-1 also has an observation window for visual experimentation. A glass cover plate 1-2 is placed under the top cover 1-1 and is fixed to the top cover 1-1 using 704 silicone rubber. This serves to compress the microchannel section 1-3 and prevent leakage of the working fluid.

[0036] Microchannel segment 1-3 is closely attached to the lower part of glass cover plate 1-2. The size, number, and thickness of the channel are determined according to experimental requirements. Thermocouples arranged in a fixed order and at fixed intervals are inserted 25mm above the base of microchannel segment 1-3 for temperature measurement. Heating section 1-6 is installed at the lower part of microchannel segment 1-3, and a base plate 1-7 is provided at the bottom of heating section 1-6. Thermocouple base holes are also provided at corresponding positions on the base plate 1-7 to fix the thermocouples.

[0037] Furthermore, the microchannel section 1-3 is detachable and connected to the base plate 1-7. A groove is excavated near the bottom of the main body to accommodate O-rings, which are used to seal the glass cover plate 1-2 and the microchannel section 1-3. The inlet 1-4 and outlet 1-5 are also accurately connected to the base and top plates using tensile bolts. Matching grooves are excavated on these sections for O-ring compression sealing. The inlet and outlet pipe sections are connected to the entire experimental circuit via flanges. The heating section 1-6 uses an electric heating rod for heating. Adjusting the heating rod power allows for adjustment of different heat flux density experimental conditions. The entire section is made of copper, which provides excellent heat transfer.

[0038] The working process of the plate-type microchannel organic working fluid boiling heat transfer test system described in this invention is as follows: Step 1: Before starting the experiment, turn on the signal acquisition system of the entire system. Observe the pressure and temperature in the circuit using pressure sensor 12 and thermocouples to perform initial state detection. After confirming that there are no abnormalities, fill the storage tank 1 with the working medium, then open the valve of storage tank 1 and the working medium pump 2 to allow the working medium to flow fully in the circuit. The pressure of the circuit can be stabilized using a pressure stabilizing tank filled with nitrogen, or the pressure can be adjusted using the back pressure valve 3.

[0039] Step 2: After sufficient flow for a period of time, first turn on the pump in the constant temperature water tank loop of cooler 9 to input cooling water, then turn on the electric heating power supply of preheating section 6 for preheating, and continue to monitor temperature and pressure changes through the acquisition system. If no abnormalities are found, turn on the electric heating device of experimental section 10 to heat experimental section 10. Temperature data is monitored by thermocouples in experimental section 10, and visual data is collected by capturing images in the visualization window using a high-speed camera. The mass flow rate in the loop can be monitored by flow meter 4, and different mass flow rates can be adjusted by adjusting the handwheel of regulating valve 5. After collecting sufficient data, turn off the heating device of experimental section, continue monitoring temperature and pressure, and turn off the preheating section heating device and cooling water loop pump after no abnormal fluctuations are found.

[0040] Step 3: After the system pressure drops to the minimum, close the inlet and outlet valves of the experimental section to replace the microchannel sections 1-3. The liquid storage tank 1 is set at a low position to utilize gravity.

[0041] If the experiment is not to continue, close the outlet valve of storage tank 1 and open the inlet and outlet valves of experimental section 10 to discharge the working fluid through the drain outlet.

[0042] After the liquid has drained, close the remaining valves and working fluid pump 2. When conducting experiments under marine conditions, place the entire system on a six-degree-of-freedom platform. With all other operations unchanged, open the six-degree-of-freedom platform before heating experimental section 10 to drive the experimental system in the specified motion pattern, followed by subsequent experiments and data monitoring. After collecting sufficient data, close the six-degree-of-freedom motion platform; subsequent processing is the same as in non-marine condition experiments.

[0043] The device of this invention is reliable, easy to operate, and has stronger functionality than other similar experimental devices, enabling it to better carry out related scientific research.

[0044] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating orientation and positional relationships are based on the orientation and positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0045] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A plate-type microchannel organic working fluid boiling heat transfer test system, characterized in that: It includes a closed-loop connected liquid storage tank (1), working fluid pump (2), preheating section (6), experimental section (10) and cooler (9); The experimental section (10) includes a top cover (1-1), a glass cover plate (1-2), a microchannel section (1-3), a water inlet (1-4), a water outlet (1-5), a heating section (1-6), and a bottom plate (1-7). The top cover (1-1) is provided with an observation window. The glass cover plate (1-2) is placed under the top cover (1-1). The microchannel section (1-3) is close to the lower part of the glass cover plate (1-2). A thermocouple is provided at the bottom of the microchannel section (1-3). The water inlet (1-4) and the water outlet (1-5) are respectively provided at both ends of the microchannel section (1-3). The heating section (1-6) is installed at the lower part of the microchannel section (1-3). The bottom plate (1-7) is provided at the bottom of the heating section (1-6).

2. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 1, characterized in that: The plate-type microchannel organic working fluid boiling heat exchange test system also includes control equipment, which includes a back pressure valve (3) and a regulating valve (5). The back pressure valve (3) and the regulating valve (5) are set between the working fluid pump (2) and the preheating section (6) to regulate the working fluid pressure and the working fluid flow rate, respectively.

3. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 2, characterized in that: The control device includes a pressure regulator. A pressure regulator is provided between the working fluid pump (2) and the back pressure valve (3). The pressure regulator is a pressure stabilizing tank filled with nitrogen.

4. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 2, characterized in that: The control equipment includes a first DC power supply (7) and a second DC power supply (11). The first DC power supply (7) is connected to the preheating section (6), and the second DC power supply (11) is connected to the experimental section (10).

5. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 2, characterized in that: The control device includes a constant temperature water tank (8), which is connected to a cooler (9).

6. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 2, characterized in that: The preheating section (6) includes a stainless steel pipe and an insulating flange. The first DC power supply (7) electrically heats the stainless steel pipe to achieve preheating, and a thermocouple is installed at the outlet of the stainless steel pipe for temperature measurement. Insulating flanges are installed at both ends of the stainless steel pipe for insulation.

7. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 1, characterized in that: The plate-type microchannel organic working fluid boiling heat exchange test system also includes measurement and monitoring equipment, including a flow meter (4), a thermocouple and a pressure sensor (12). The flow meter (4) is located between the working fluid pump (2) and the preheating section (6) and is used to measure the working fluid flow rate. Thermocouples are arranged on the preheating section (6) and the test section (10) to measure the temperature. A pressure sensor (12) is set between the preheating section (6) and the test section (10) to measure the pressure in the circuit and in the test section (10).

8. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 1, characterized in that: The working fluid pump (2) is a mechanically driven diaphragm metering pump.

9. The plate-type microchannel organic working fluid boiling heat transfer test system according to claim 1, characterized in that: The cooler (9) is a tubular heat exchanger made of 316L stainless steel.

10. A method of using the plate-type microchannel organic working fluid boiling heat transfer test system as described in claims 1-9, characterized in that: Specifically, the following steps are included: Step 1: Before the experiment begins, the signal acquisition system of the entire system should be turned on. The pressure and temperature in the circuit should be observed through the pressure sensor (12) and thermocouple to perform initial state detection. After the detection is normal, the storage tank (1) should be filled with working medium. Then, the valve of the storage tank (1) and the working medium pump (2) should be opened to allow the working medium to flow fully in the circuit. The pressure of the circuit should be stabilized by the pressure stabilizing tank filled with nitrogen and the pressure should be adjusted by the back pressure valve (3). Step 2: After the working fluid has been flowing for a period of time, first turn on the pump of the constant temperature water tank (8) loop in the cooler (9) to input cooling water, then turn on the first DC power supply (7) of the preheating section (6) to preheat, and continue to monitor the temperature and pressure changes through the acquisition system. If there is no abnormality, turn on the electric heating device of the experimental section (10) to heat the experimental section (10), monitor the temperature data through the thermocouple of the experimental section (10), collect the visualization data through the high-speed camera, monitor the mass flow rate in the loop through the flow meter (4), and adjust the mass flow rate by adjusting the handwheel of the regulating valve (5). After collecting enough data, turn off the heating device of the experimental section and continue to monitor the temperature and pressure. After there is no abnormal fluctuation, turn off the first DC power supply (7) of the preheating section (6) and the cooling water loop pump. Step 3: After the system pressure drops to normal pressure, close the inlet and outlet valves of the experimental section and replace the microchannel section (1-3). If the experiment is not to continue, close the outlet valve of the storage tank (1) and open the inlet and outlet valves of the experimental section (10) to discharge the working fluid through the drain outlet. After the liquid is drained, close the remaining valves and working fluid pump (2). When conducting experiments under marine conditions, place the entire system on a six-degree-of-freedom platform. With the other operations unchanged, open the six-degree-of-freedom platform before heating the experimental section (10) to drive the experimental system to perform a specified form of motion. Then conduct subsequent experiments and data monitoring. After collecting enough data, close the six-degree-of-freedom motion platform. The subsequent processing is the same as that for experiments under non-marine conditions.

Images